| Author |
Message |
william edgar (Honkytonk1) (216.96.18.96)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 5:27 pm: | |
If I do not use the coach heat and or air can I start and run my MC-8 8V-71 Turbo up and down the road using only 2 heavy duty 12 volt pickup batterys? If I run the coach heat other than the drivers defrost will it drain the battery's faster than the electrical system will replace the energy? |
william edgar (Honkytonk1) (216.96.18.150)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 9:13 pm: | |
I just checked with the Bus Guru and everyone's friend Fred Hobe at Coach Conversion Central and he said you can use 2 12 volt Heavy Duty Light Truck Battery's like they sell at Wal Mart. They are about 950 amp hours and together that's 1900 amp hour's and plenty to start your coach. You just can not run the coach heat or air. |
Sam Sperbeck (204.248.119.254)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 9:36 pm: | |
Hi William,
I disagree that you can't run the coach heat with smaller batteries, at least going down the road, if you still have the large alternator. At highway speed your alternator will easily provide enough power to run your heater blower(s), and even when stopped if you use high idle. I have two group 31 batteries in our 4106 and use the heater and defroster when it is cold. Usually the defroster is enough for comfort if it isn't too cold. |
Geoff (Geoff) (66.238.120.150)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 10:16 pm: | |
The problem with using two "truck" batteries (what group?) is that they may be able to start your engine in warm weather, but once it cools off and your engine decides not to start right away they will drain very quickly leaving you with a clicking solenoid. The bus heat or air conditioning has nothing to do with this-- if the enigne is running the generator/alternator provides the power needed. I suggest keeping the original battery setup (2- 8D's?) or rigging a system where you can jump off the house batteries if needed. |
DonTX/KS (66.82.9.16)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 10:26 pm: | |
Of couse, if you replace with a couple of 900ah 8d batteries, instead of a pair of Gp 31 1100ah batteries, the cold only really knows CCA or cold cranking amps. And as I found, at NAPA you can get a pair of NON PRORATED 60 month warranty batteries in Gp 31 1100 cca for less than the two 8d batteries, and nobody gives much of a warranty on an 8d. None of the 8ds ever cranked my bus like the Group 31 jobs did. Years later and they are still performing like new.
I have two friends who use standard car batteries in their 8v71 powered conversions, and they never have a problem. (they stay away from the very cold weather too)
Although bigger is better with batteries, the capacity of the battery should be considered as well. |
James Maxwell (Jmaxwell) (66.81.40.38)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 10:40 pm: | |
As Don points out, Gp31 1100ah are equal to the standard 8d's in CCA, about 1/3 the size, and cheaper. I have 2 Trojan Gp31's on my 6v92ta and I also run the bus heat fan off of them and the bus AC back before I blew the compressor. Condenser fans have their own alternator, 36v. Last time I checked they were $92 ea., I think model C-31 |
Jayjay (64.12.96.105)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 25, 2004 - 11:14 pm: | |
When my 8-D's died of old age I replaced them with 950 CCA group 31's from AutoZone (Interstate or Gould) for $60.00 each. (5 Year pro rated warranty/100% replacement for the first two years) They start my tired old 8V71 in my 4905 just fine...all the way down to 22 deg. Below that you're on your own. They are about 1400 amps of normal capacity, and that's more than enough to weld 1/2" plate steel, so be careful. I run halogen head lights, the defroster, the stereo and the toad system concurrently with no problem. You should have no problem with them. ...JJ |
Doug (68.82.242.218)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 26, 2004 - 2:24 pm: | |
New 8D's ar 1200 or better CCA each depending on the maufaturer. well in line with group 31.
they can readily be had for 120.00 each and sometimes cheaper.
beneifits of listening to the rooms full of engineers.....CCA, reserve capacity.
battery life has nothing to do with CCA or reserve capacity, but rather use and maint.
after installing my new batteries 6 years ago I put a solar cell on the roof air and wired it to the batteries.......basically whenever the sun shines I get a trickle charge...... started the bus about 2 weeks ago..... temp around 30..... 2nd attempt......vroooom. no starting fluid.
I just say, don't try to out engineer the engineers. especially when there was a room of them. |
dougthebonifiedbusnut (24.62.99.43)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 26, 2004 - 7:45 pm: | |
Once the alternator is providing power "it" providse all the power for running things the batterys just sit there getting charged, doesnt matter what you run. I have four group 31's gives me 3000cca and if one quits its real easy to handle the bad battery. those 8d's are heavy.
two truck batterys are fine but like it has been said stay in the warm weather. |
FAST FRED (63.233.189.3)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 27, 2004 - 6:01 am: | |
For running tiny batterys it does pay to stay in warm weather ,
But it also pays to toss the stock dumb Voltage regulator .
The big heavy 8D's not only contain far more power than tiny truck batts they are loads better to handle the usual constant overcharge from the simple minded stock V reg.
The orig setup was expecting to have a 160A load from the blowers , plus the lights,defroster and other small loads.
Usually the Coach heat is removed and the dumb OF ON V reg will boil the battset after a really long day.
Lowering the V reg charge voltage to 13.5 or so solves the hassle for 8D's , but might not for a batt set of 1/3 the weight.
Good Luck,with experiments,
FAST FRED |
Phil Dumpster (24.16.189.48)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 28, 2004 - 9:08 am: | |
Don't confuse Cold Cranking Amps with battery capacity. CCAs are a factor of plate area, capacity is a matter of volume.
The reason why the engineer who designed the coach specified group 8D batteries was to provide a backup safety margin in case the charging system of the coach failed. The idea is that the batteries will have enough capacity to get the bus full of passengers to the next scheduled station stop under the worst of conditions.
While you probably don't need that in a bus conversion, especially if you have a generator with a big 12 volt alternator on it, do consider this - starting your bus will draw the group 31s down father percentage-wise than it would the 8Ds. Starting batteries tend to age more quickly this way.
If you only use your bus during the summer, a few times a year, then group 31s may work for you. Group 8D batteries would probably expire from old age before you wore them out in this case.
However, if you use the bus every weekend, you'd probably kill the group 31s within a few years time. In commercial service, they wouldn't last long at all.
Here's a hint for cheap group 8D batteries - find out who has the contract to supply your local transit system with batteries. In Seattle, Dyno Batteries http://www.dynobattery.com supplies the local transit agencies. Most transit agencies don't service their own batteries anymore, preferring to outsource that to a contractor. If a coach winds up with dead batteries, they replace the batteries from new stock and send back the dead ones to the supplier.
The supplier then checks them for damage, slow charges them, and offers them for sale at bargain prices. I paid $75 each for a pair of 8D batteries for my bus, and they came with a 5 year warranty. They were only 6 months old. |
Gary Carter (68.25.58.216)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 28, 2004 - 4:04 pm: | |
According to the Excide (GNB) website the group 31 has a RC@25amps of 160 minutes and an 8D has a RC@25amps of 450 minutes. RC is reserve capacity. |
FAST FRED (65.154.177.254)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 29, 2004 - 5:35 am: | |
RC is a discharge at 20 or 25A till you get down to a specific voltage .
Was an early measure to attempt to figure how long you could drivce with headlamps and running lights on .
IT is a fair measure of the actual capacity of a battery ,
not the batts ability to make a one time blast for seconds.(CCA)
FAST FRED |
DonTX/KS (66.82.9.68)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 31, 2004 - 8:24 am: | |
Phil, you say: "However, if you use the bus every weekend, you'd probably kill the group 31s within a few years time. In commercial service, they wouldn't last long at all." I don't know why you would make such a statement.
If you visit a truck stop some time, check out the very commercial trucks, with far more mighty engines than our little bus would use even. You will find ONLY group 31 "tiny" batteries doing commercial service EVERY day. A group 31 IS a commercial use battery. Are we really talking about the same thing here? |
Phil Dumpster (24.16.189.48)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 31, 2004 - 1:24 pm: | |
No, Don, we aren't. For one thing, the engines those group 31s are cranking are 4 cycle engines equipped with glow plugs. They draw a hundred amps for a few seconds to heat the glow plugs, they they draw 5 to 600 amps for a few more seconds to crank the engine.
Two cycle Detroits generally don't have glow plugs and have to be cranked longer to start, especially in cold weather. Hence, it take more energy to start an 8v71 than it does to start a 12.7 series 60.
A group 65 battery is also a commercial use battery, but if you try to start your 2 cycle detroit with it you might damage it badly. It's not a matter of use, it's a matter of size. Group 31 batteries are just too small for an MC9 equipped with a series 92. That's why MCI specified group 8D batteries.
My Flyer D901 was also designed to have a pair of 8D batteries. If group 31 batteries would have been enough, Flyer would have specified them, but they didn't.
Maybe they're just not as smart as you. |
NEO/Russ (170.224.224.38)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 31, 2004 - 3:01 pm: | |
GLOW PLUGS????? At least get the facts right. I've a 500hp Series 60, 12.7l Detroit that doesn't have any glow plugs. Probably was an option, but not standard. It also didn't come from an application that ran huge air conditioning fans like most commercial buses. A S60 starts fast if it has good rings and valves. If just for starting, I don't see why a pair of 31's wouldn't start an 8V that's in good shape. Besides, ever lift these "tiny" group 31's? Pulled 8D's out putting 31's in, seems like there are more engineers designing diesel powered trucks than buses........... |
DonTX/KS (66.82.9.19)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 31, 2004 - 3:21 pm: | |
I was not trying to argue or be smart or nasty Phil, but still disagree (I think we are allowed to do that).
First off, the big Cat engines do NOT have glow plugs, and my 3406 took much longer to crank than my almost instant starting 8V71 two stroke. Again, trucks have used 6-71 and 8V71 (and 92) for MANY years, not a single one of them used an 8d size battery.
I do not have a Flyer manual, but my 4905 NEVER mentioned 8d batteries, but DID specify the amps, which a modern Gp 31 far exceeded. |
Geoff (Geoff) (66.238.120.103)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 31, 2004 - 3:28 pm: | |
Four Group 31's are the standard, replacing two 8D's. It has been this way since the early eighties. |
DonTX/KS (66.82.9.19)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 31, 2004 - 4:12 pm: | |
Are we still talking trucks or buses? My 1989 Kenworth W900L, Cat 3406B 425hp engine came with two group 31 batteries, with space to add one more if you wished. I don't think I could have put four in it if I wanted to. I had it at Kenworth dealers a number of times, as well as Cat dealers, never heard anyone suggest I needed more, or had gotten ripped off.
My friend running two car batteries in his Eagle for years has been greatly amused by this discussion. (And keeping with BNO tradition, has nothing to do with the original question of course) |
Geoff (Geoff) (66.238.120.103)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 31, 2004 - 4:36 pm: | |
The only trucks I have ever seen that only used two Grp 31 batteries were medium duty trucks. But I don't work on trucks all the time. Don-- if you would have looked on the other side of the truck you probably would have found two more batteries--LOL (?--I believe you Don, just kidding). |
Tony (64.215.196.161)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 31, 2004 - 5:16 pm: | |
OK guys, I have a 1985 Eagle that I put a Cummins engine Into and It has 2 car batteries ( 750 CCA ) and everything works just fine, it starts like Its supposed to even at 15 Degrees and the starter seems to have lots of torque, The Eagle only had 3 Car Batteries when I bought It. |
Geoff (Geoff) (66.238.120.103)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 31, 2004 - 7:11 pm: | |
Tony-- does your Cummings have a gear-reduction starter motor? I can't imagine starting a cold diesel at 15 degrees with two car batteries. It just doesn't work-- four batteries are barely enough in that temperature. |
cjm (65.132.121.173)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 31, 2004 - 7:46 pm: | |
Geoff, my MCI-8 has been using two car batteries from Wally World to start its 8V71N for almost 3 years. It was 18 degrees Monday and it started right up. The last 4 sets of 8D's I had in it lasted about a year each; just enough to get out of warranty. Each set was a different manufacturer, Exide, GNB, Deka, and I can't remember who made the first set, so I don't think it was a bad run. They were replaced in pairs. I think the Wally World batteries spin the 8V71 faster than the 8D's ever did, they've done it for 3 times as long, and they still have 3 years warranty left on them. Fred Hobe recommended using these batteries; he has used them in his MCI-8 with an 8V71T tank engine for even longer. I know they work in my bus. They may quit tomorrow, but, up till now, they have worked perfectly. YMMV, John |
DonTX/KS (66.82.9.28)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 31, 2004 - 9:19 pm: | |
OK Geoff, I DID look on the other side, seemed the Kenworth people thought that space should be used for a utility box, to carry oil, filters and coolant. Nobody can argue that more is better, three or four would be a great choice if operating in the cold consistantly, but personally for bus use, I would rather start the genset, warm the DD with a block heater, and happily crank it up. No, I take that back, if it was that cold I would have left for warmer climate several days before, after all, have we forgotten what the heck a bus is FOR? (gonna be 76 here tomorrow by the way) |
Geoff (Geoff) (66.238.120.103)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, January 31, 2004 - 10:59 pm: | |
Happy birthday, Don!!
(I'll stick to 4 Grp 31's, you never know when you need that extra reserve).
--Geoff |
Johnny (63.159.201.244)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 01, 2004 - 8:13 pm: | |
Uhh, MOST big engines don't seem to have glow plugs--even the Cummins 5.9 doesn't use them.
And, uhh, my friend's GMC 10-wheeler with the very same 6-71 used in many buses runs a pair of 31's. I've also seen a GMC General semi tractor with a Detroit (either an 8V71 or 8V92) that looked like it used 31's. |
Sam Sperbeck (204.248.119.254)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 01, 2004 - 8:42 pm: | |
Hi Don,
"(gonna be 76 here tomorrow by the way)". I thought you were refering to the temperature, but Geoff wished you happy birthday, which is it? Just curious!
Thanks, Sam Sperbeck
La Crescent, MN |
jim mci-9 (209.240.205.60)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 01, 2004 - 9:11 pm: | |
the cummins uses a heat grid in the intake for a heater....lots of cat engines use them...3304's...3306's... 3400's...the 6's 8's and 12's...but with precombustion chamber injection, not direct injection fuel systems...detroit never has used a glow plug in any engine... the series 40 that detroit markets is a international harvester design.. the dt380, 466, or 530.. it has glow plugs.... the huge slow-turning (540) rpm fairbanks morse engines used a light-able wick for its glow plugs.... kinda expensive till the users figured out that a non-filter cigarette would work just as well.. |
DonTX/KS (66.82.9.39)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 01, 2004 - 9:34 pm: | |
Hey Sam, Geoff is just being mean to me, some kids are like that. I was referring to the temperature, and was incorrect, it was 78 here today. |
DonTX/KS (66.82.9.39)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 01, 2004 - 9:38 pm: | |
Battery Size - DDEC or not. Trivia related to the post original topic. Why does it take MORE battery to start an electronic version DD than it takes to start the old ones. Lets see who is first with the correct answer! (Jim or Geoff don't get to respond) |
BrianMCI96A3 (69.34.169.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 01, 2004 - 10:42 pm: | |
First of all, if you have a pair of batteries that add up to the cranking amps needed to turn over your particular application, then in ideal conditions regardless of their size they will spin your engine and most likely start it time and again.
However, ideal conditions aren't what we generally have to work with, and the larger the reserve capacity of any battery bank, the worse the conditions it is able to handle for longer periods.
By ideal conditions I mean a mild mid-summer day, AND an electrical system that is in PERFECT shape,
with NO other draws on the batteries.
As Sam and doug mentioned, once the engine is running, the alternator becomes your energy source, and in the case of an 270 amp oil cooled monster, will give you enough power to run every single accessory, and maybe a little welding besides.
Don is right, by far the battery of choice is a group 31 for nearly every single heavy duty application in our fleet, and two is the usual number though, on occaision I have seen four together.
Phil, as a rule the heavy duty 4 cycle engines we've dealt with do not have glow plugs. AND we have and have had A LOT of 8V92 Detroits that run on two Group 31's. Oh, and while this is a warm climate town, it does on occaision get into the teens and twenties, and even then a well tuned DD in good condition will usually light right off.
Like Geoff says, you never know when you will need the extra reserve, and Phil is right the coaches in service were given 8D's for exactly the reasons he mentioned "...to provide a backup safety margin in case the charging system of the coach failed. The idea is that the batteries will have enough capacity to get the bus full of passengers to the next scheduled station stop under the worst of conditions."
However, four group 31's scrupulously maintained with well kept terminals and wiring will provide good performance compared to two 8D's; The main knock on 4 batteries vs two, is the maintenence involved in keeping those batteries and their additional wiring and terminals in good condition.
By far the most stellar statement on this thread was Fast Fred's replace your old "dumb" regulator if you are going to go with smaller batteries, though I would install an electronic even if I wasn't going to run smaller batteries.
Brian |
Doug Dickinson (Dougd470) (65.161.188.11)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 02, 2004 - 10:14 am: | |
Here is the story I got from the engineers at NJ Transit when I worked there -
8Ds are there for a couple of reasons in the transit industry (and I am speaking of the MC9s that many of us own). I guess it applies to other coaches also, but use your own discretion).
1) Coaches are started several times a day in transit service. Each time you start a coach, you draw energy which is replaced. This is a cycle. Depending on how deep that cycle is, (i.e. how long cranked and energy drawn down and replaced) will affect the life of the battery.
2) In summer, the 3.5 HP of blowers draw LOTS of amps. When the engine is at idle, it is not replacing that energy as fast as it is drawn down, so there is another "cycle" and the question of how bad for the battery depends again on how deep the discharge.
3) You need a biiiiig battery to spin a 6V92 in sub freezing weather. When you have dozens - maybe even 75 buses leaving in a one hour period from a single garage is not the time to create a jump-the-bus situation. The extra energy in an 8D is worth the cost and size.
Now - I have to say that batteries today are somewhat better and seem to have more energy per pound, but the old 8D still has it's place in the bus service. In a diesel truck, it is not running the huge AC plant like we have and the engine may not be starting from sub freeezing temps every day (depending on the service). In addition, OTR trucks rarely have stone cold engines when in revenue service. My son's truck probably hasn't been shut off for more than 6 hours in a year.
So - that's what I heard. I might use some Grp 31s in my MC9 coach, but I also will have a block heater, a built-in charger unit to keep batteries in tip-top shape when on the road, and probably won't be using it much in sub-freezing temps. When I add the invertor, I will ahve a second, and larger, 24V plant so the issue is really moot at that point.
My $0.02 worth. Your milage may vary.
Doug
St Louis MC9 |
BrianMCI96A3 (69.34.169.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 02, 2004 - 12:19 pm: | |
I do believe Doug has nailed the issue down.
To my way of thinking using a plug-in block heater, or a diesel fired coolant heater, in sub-freezing weather is the route to take.
In any case, most of us, will not idle our busses for long periods of time, many of us will no longer even have the 3.5 HP fans Doug mentions, and more than a few of us will avoid cold weather like it was the Plauge!
The bottom line is that the charging system in a bus wearing it's service livery is a different creature than a bus wearing a conversion!
There certainly is nothing wrong with using 8D's in your conversion, or using a pair of 4D's, or FOUR group 31's... but a pair of WELL MAINTAINED
group 31's used merely as starter batteries are adequate to the task.
Brian |
Geoff (Geoff) (66.238.120.24)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 02, 2004 - 2:26 pm: | |
They might be adequate to the task of starting your engine, but they are not up to the task of prolonged cranking if you have a problem starting the engine-- dispite warm weather or engine heaters. I don't understand why so many people are convinced that having a marginal chassis battery bank is okay, since I work as a mechanic I see the ugly side all the time, and having that extra cranking power is worth every penny or room the extra battery or two takes. That is why I said at the begining of this thread if you want to run with two small batteries for your engine you should have a way of jumping off your house batteries when you need it.
--Geoff |
jim mci9 (209.240.205.60)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 02, 2004 - 5:23 pm: | |
nobody's answered dons' question.... so why does it take longer to crank an electronic engine than a mechanical??? don ought to come up with a reward for the correct answer.....but since i'm ineligible.... |
DonTX/KS (66.82.9.33)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 02, 2004 - 8:48 pm: | |
Cool it Jim! If they don't know, they can't answer. I put a trivia on the MAK board with no takers either, but that is a class of lower intelligence I have been told. |
jim mci-9 (209.240.205.60)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 02, 2004 - 8:57 pm: | |
hey be nice.. the " man show " is gonna be mak's centerfold....they sent me all the info to get it in.... |
BrianMCI96A3 (69.34.169.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 02, 2004 - 9:03 pm: | |
Well, Geoff if you read my last post carefully you will see that not only do I advocate WELL MAINTAINED batteries, but I stated that a well tuned and good condition DD should crank right up.
Since I have been a diesel mechanic for nearly a quarter of a century, I see and have seen, the "ugly side" all the time. By far the number one problem I encounter with charging/starting systems is poorly maintained batteries.
I disagree with you that two group 31's are marginal, in my experience, two group 31's in good condition and fully charged will crank over your DD LONG after you have determined that you have a serious problem and your Detroit wouldn't start even if you had 10 8D's.
Having extra reserve is a good thing, but in terms of need, two group 31's will do the trick, and of course it wise to be able to jump your coach from the house batteries, but that is simply insurance.
Brian |
DonTX/KS (66.82.9.69)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 02, 2004 - 9:52 pm: | |
More fuel for the fire. I just spent a week in Nevada, a lot of time at Nevada Ready Mix, it happens my son's stepbrother is the heavy truck maintenance supervisor for Nevada Ready Mix.
I just had a chat with him, he has been maintaining their 250 plus heavy trucks for decades. Their trucks run hard, often two shifts a day on a truck, lots of engine starting and stopping. Their experience is that two group 31's is by far the best choice, and most of their trucks came that way, they have converted the oddballs to that configuration (including the old series/parallel ones). The added headaches with three or four, due to one going bad and sucking the rest of them far outweigh the added cranking power. Their inhouse rule is that you can use three gp 31 650 amp or two 925 amp ones. Not one truck in the entire fleet has four batteries, not one truck in the fleet has an 8d, not one truck in the fleet has ever felt the need for anymore.
That is one maint supervisor, one fleet, at one location, but it works well for them. |
LarryK2LT (66.190.109.141)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 02, 2004 - 9:55 pm: | |
::Why does it take MORE battery to start an electronic version DD than it takes to start the old ones.
The DDEC requires a minimum voltage to function. A battery that is too small will have its voltage pulled down by the starter below the minimum. MORE is better.
LarryK2LT |
Geoff (Geoff) (66.238.120.24)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 02, 2004 - 11:03 pm: | |
We aren't running fleets of trucks here, we are running buses. We aren't parked at a big garage with portable battery jumpers and a crew of mechanics. A lot of our buses are old and not in the best condition, and most of us have them sitting around a lot so they are not always easy to start. How about the people who run out of fuel? Or the people who get air in the fuel system and have to crank longer to start? I guess if someone wants to follow the minimum battery crowd they have only themselves to blame when they run out of charge before the engines fire, and they have to go through multiple pains to get their engines running.
Are we through yet?
--Geoff |
BrianMCI96A3 (69.34.169.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 1:00 am: | |
No Geoff we aren't, I repeat, 2 group 31's is what we as a fleet use, in vehicles that came OEM with two group 31's AND it's practically the standard in the industry.
Don's post simply adds to the case for 2 group 31's, you think in THIS town that cement companies can afford to have their trucks downed all the time, even just long enough to get a jump start?
I don't blame you for wanting extra batteries with the extra reserve...But if you don't maintain them properly, batteries will not last no matter how many you have.
Brian |
FAST FRED (65.150.247.104)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 5:56 am: | |
MY WAY.
Since its the weight of lead that represents power, our conversion uses a bank of 2 31 little trucky batts and 4 large golf carts more lead and weight than the orig 8D's.
The series 31 sits on the stock shelf with the 2 golf carts, there are two shelves.
When operating normally the system is seamless and we flit about in horrable cold weather , IF its necessary , or stop O nite with narry a worry, and full use of the propane 42,000BTU furnace.
IF we go boondockin its ONLY in fine weather , so I simply disconect the two 31's from the system.
Eventually an MCI disconect will be wired in (more V loss but more convienent )as they can be operated with a remote pull cable.
This solves most of the hassles ('Cept cost) .
6 tiny batts are EZ to carry and install , tho more juice is lost from the conections.
We can dry camp in fine weather on the 4 golf carts , and still get started from the 2X31's.
In std operation , nothing needs to be done except drive.
The only extra work caused is after a boondock the coach system will happily recharge the setup , but the bolts MUST be pulled again to give an Equalizing charge to the golf carts to keep 100% capacity avilable, start batts like 31's don't like equalizing.
A Bonus is I can "steal " batts if needed to use on my boat , and there not as insane to lift aboard as an 8D from a dink.
Works for ME!,
FAST FRED |
DonTX/KS (66.82.9.26)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 8:27 am: | |
Not quite the answer I was looking for Larry, but very valid point. I was assuming that the batteries for both engines were ADEQUATE, and then the question is why the electronic engine will always take more of the adequate juice to get started, in fact usually several times as much juice to get it started. Come on guys, think! |
BrianMCI96A3 (198.81.26.45)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 11:49 am: | |
Well Don, since no one else seems willing to post an answer, I'll give you my thoughts on that topic.
As the DDEC computer uses sensors to determine engine timing, depending on what position the engine stopped it COULD take up to two engine revs for the computer to be able to determine engine timing, right after that, the engine will light.
Since a well tuned mechanical DD will fire off within the first revolution, it could take a DDEC engine four times as long to fire up.
Brian |
dougd470 (65.161.188.11)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 11:53 am: | |
I think we are chasing this rabbit in a circle. Either way will work - it just depends on what works for YOU, not ME or anyone else. Sure GP31s work, and you can start a diesel on smaller batts, most of the time.
As for the DDEC 2 and 3 needing voltage - they are correct. NJT had some problems with that until they found out where the problem was. Another way is to "split" the batts on starting command so one is running the computer and one is spinning the engine (I heard that one works). In any event, it don't matter which battery you choose, if you don't maintain it, the issue is going to be moot at the worst possible time (murphy's law).
Doug
St Louis MC9 |
DonTX/KS (66.82.9.30)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 2:09 pm: | |
You got the prize Brian! I can't remember what it was even. The oldies will fire on the first compression stroke usually, and the DDEC takes as you say a couple of revolutions to get the computer all smarted up on where everything is at.
A friend of mine with a fleet to maintain, claims that is only a theory, in practice it seems to take longer than just the 2 revolutions to fire, I suppose "computer lag" or some such thing makes it appear that way, I dunno since I never had a chance to play with the new fangled stuff.
Congratulations!. |
Geoff (Geoff) (66.238.120.24)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 2:46 pm: | |
Don, didn't LarryK2LT give the same answer?:
"The DDEC requires a minimum voltage to function. A battery that is too small will have its voltage pulled
down by the starter below the minimum. MORE is better. "
I like the "MORE is better"-- good thinking.
--Geoff (ineligible) |
BrianMCI96A3 (198.81.26.45)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 2:54 pm: | |
(bowing)Thank you Don, the only reason I answered the question is because it looked as though no-one else was going to.
After all, I work with this stuff daily, I'm sitting about 40 ft. from a DDEC rig as I type.
Brian |
DonTX/KS (66.82.9.13)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 5:35 pm: | |
Nah Geoff, the question was why it took more battery juice, and the answer was because it takes more juice to spin the engine the two or more revolutions if DDEC before it will even think of starting, and only a fourth of a revolution if it is not a DDEC. Therefore, a DDEC takes four times as much juice to start.(plus a little bit for the sensors and computer too). Trivia. Practically worthless knowledge. Something to bet a beer on. |
RJ Long (Rjlong) (66.229.97.200)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 5:54 pm: | |
One thing I found out about starting any of the electronic engines is that if you turn on the ignition (or master switch) and wait a few seconds for the "check engine" light to go out, they'll start almost as quickly as an MUI unit.
But if you hit the starter switch immediately after the ignition, it takes a LOT longer for them to light off, as you haven't given the computer time to boot up first. And some buses, especially those with an air starter, will deplete the air supply before they'll start if you don't let the light go out first.
Just like these crazy boxes we're using to post these messages. If we don't let them boot up first, nothin's gonna happen!!
Don - wasn't the prize a couple of expired city transit transfer slips??
RJ
PD4106-2784
Fresno CA |
jim mci-9 (209.240.205.60)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 7:25 pm: | |
ougtha be worth dinner in progresso at angels" |
Johnny (63.159.192.200)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 9:51 pm: | |
"the cummins uses a heat grid in the intake for a heater....lots of cat engines use them...3304's...3306's... 3400's...the 6's 8's and 12's...but with precombustion chamber injection, not direct injection fuel systems...detroit never has used a glow plug in any engine... the series 40 that detroit markets is a international harvester design.. the dt380, 466, or 530.. it has glow plugs.... the huge slow-turning (540) rpm fairbanks morse engines used a light-able wick for its glow plugs.... kinda expensive till the users figured out that a non-filter cigarette would work just as well."
Detroit absolutely did build engines with glow plugs, but I doubt any were used in buses.
AFAIK, the International DT380/466/530 (awesome engines, BTW) have no starting aids--no plugs, no heater, & still fire up pretty well in the winter. IIRC, the only IH engines with glow plugs are the V8's: the 420/444IDI (used in Ford trucks as the 6.9 & 7.3 IDI), the T444E (different software made it the 7.3 litre PowerStroke), & the VT365 (6.0 PSD). |
DonTX/KS (66.82.9.44)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 03, 2004 - 10:17 pm: | |
So I am yearning to learn. Trivia of the day, just which DD engines used glow plugs? Does anybody get a prize? |
Geoff (Geoff) (66.238.120.24)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 04, 2004 - 12:15 am: | |
6.2, 6.5, 6.6 |
BrianMCI96A3 (69.34.169.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 04, 2004 - 12:23 am: | |
DDEC does require a minimum voltage BUT if your batteries aren't capable of that voltage while cranking, your batteries are nearly dead.
And while a non DDEC engine MIGHT fire off under such conditions, it's going to be an extremely rare occurance.
Brian |
BrianMCI96A3 (69.34.169.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 04, 2004 - 8:12 am: | |
To tell you the truth, I'm not sure Detroit Diesel would lay claim to the 6.2 6.5...
Brian |
Geoff (Geoff) (66.238.120.11)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 04, 2004 - 8:58 am: | |
The 6.2 was designed by Detroit Diesel while it was owned by General Motors, and the 6.5 was an upgrade to the 6.2. I mistakenly threw in the 6.6-- it was a joint venture between Isuzu and General Motors, and I don't know if Detroit Diesel got involved or not.
BTW, Brian-- what kind of diesels/applications do you work on?
--Geoff |
BrianMCI96A3 (198.81.26.45)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 04, 2004 - 11:46 am: | |
At the moment I'm working on a self propelled road broom with a 4 cyl. Cummins in it...
We have literally HUNDREDS of vehicles, from OTR transports to ten wheel dump trucks, a motor pool with numerous types of cars from Crown Victoria's to several hybrid powered Toyota Prius' AND, who knows how many pieces of equipment, from huge motor graders, front end loaders and chip spreaders down to cement mixers, weed eaters and lawn mowers... over the years I've worked on just about all of it.
Brian |
Johnny (63.159.174.37)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 04, 2004 - 8:54 pm: | |
The 6.6 Duramax is an Isuzu design--AFAIK, DD had nothing to do with it.
I also heard the 8.2 litre Detroit had glow plugs.
6.2 litre, 6.5 turbo, 8.2 litre...boat anchors, all.
DD can make a bus or tractor-trailer engine, but for anything smaller than that, I'll stick to Cummins, Cat & International. |
bobm (68.35.160.48)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 04, 2004 - 9:51 pm: | |
I kind of like my 2-53 detroit and would not trade for any 4 stroker |
Geoff (Geoff) (66.238.120.28)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 04, 2004 - 10:29 pm: | |
Brian, you are lucky to be able to work on a variety of equipment-- that way you don't get bored. I do a lot of field service at construction sites, plus I work on boats, trucks and buses, so I also get a variety of jobs to keep things interesting.
Johnny, the 8.2 is a 4-stroke, but it doesn't use glow plugs. The 6.2, 6.5 and 8.2 aren't boat anchors, they aren't bad engines, they just aren't designed to last as long or be as easily rebuilt as the bigger Detroits.
--Geoff |
BrianMCI96A3 (69.34.169.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 04, 2004 - 11:57 pm: | |
Geoff, I talked to a guy at Detroit today, when I asked, he told me that he'd heard a rumour that DD used one of it's assembly plants to build the 6.2 for GM, he wasn't sure if it was GM's design or Detroit Diesel's BUT he said they do not carry any 6.2 service parts and he didn't think that Detroit built the 6.5 for GM. (grin) like I said "I'm not sure Detroit Diesel would lay claim to the 6.2 6.5..."
I personally didn't have a problem with the 6.2 BUT it was kinda underpowered.
The 6.5 is another matter, we purchased a new street sweeper from Athey after they changed ownership, it had a 6.5 in it replacing the 8.2 Athey used to use, we replaced the engine in it three times in less than three years, and shipped it off.
Speaking of the 8.2, as I mentioned, Athey had used it in their sweepers, and for the 15 years prior to the ownership change.
Over the years we had purchased over two dozen 8.2 units during that time.
Out of all those units, covering over 15 years and untold hundreds of thousands of miles, we NEVER had to do ANY kind of engine work on any 8.2!
Brian |
Phil Dumpster (24.16.189.48)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 05, 2004 - 12:21 am: | |
Perhaps I should have written "engine preheat system" instead of glow plugs because there is more than one way to preheat a diesel for cold starting. Without some kind of engine preheat system, you're going to use a lot of battery power cranking the engine until it gets hot enough to start.
Further, as the temperature of the battery goes down, its available power drops as well.
As the EPA tightens the emissions requirements on diesel engines during the cold start phase, you are going to see more of them with engine preheat systems, such as glow plugs.
Another reason why 4 cycle diesel engines take less power to start is because only half of the cylinders are on their compression strokes during a given engine revolution. Since this is the major component of the load on the starter, the more air you have to compress, the more energy it will take to start the engine. Let's compare an 8V92TA with a 12.7 liter Series 60, since for the most part they are similar in displacement and power levels.
The Series 60 displaces around 762 cubic inches, distributed in 6 cylinders. On each revolution of the engine, three of these will have a compression stroke. This represents a compression load of 381 cubic inches.
The 8V92TA displaces around 736 cubic inches, distributed in 8 cylinders. On each revolution of the engine, all eight of these cylinders will have a compression stroke. This represents a compression load of 736 cubic inches.
If both engines have the same compression ratio, and crank at the same RPM, and crank the same number of revolutions until they start, the 8V92TA will take almost twice as much power as the Series 60. That's why the 2 cycle engine should have a battery bank with twice the capacity of its 4 cycle counterpart.
This, of course, does not take into account the additional energy needed to turn the roots blower on the 8V92TA.
Lastly, if I were programming an electronic engine control system for a diesel engine, and if cold starting emissions were restricted, I would probably program the computer to let the engine crank a few revolutions before injecting fuel into the cylinders in order to reduce the amount of unburned fuel getting into the exhaust system. Requiring the operator to crank the engine a few revolutions before allowing the engine to start would cause the cylinders to heat up, which promotes more thorough combustion of the fuel that is initially injected into the cylinder when starting. |
BrianMCI96A3 (69.34.169.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 05, 2004 - 1:10 am: | |
Firstly, Phil, having the engine spin any longer than it takes for the sensors to inform the computer where timing is on the engine, is a waste, plain and simple and I don't believe anyone will ever program an engine computer to behave in that fashion, ever.
It has always been something of a given that non-DDEC Detroit two strokes in good condition, will start within the first revolution. If it could have been worked out that the computer knows engine timing at key on, I'm certain Detroit would have built their DDEC two strokes to light off on the first revolution as well.
Another part of your logic fails because while you DO take into account that two strokes have twice as many compression strokes, causing a higher starter load, you don't seem understand that, with all things being equal, an engine with twice as many chances to create igniton will start in HALF the time, and the experience I've had with 2 and 4 strokes, bear that out.
Brian |
DonTX/KS (66.82.9.40)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 05, 2004 - 6:59 am: | |
All great points, thanks Phil and Brian, I just love it! Somehow I still question Phil's statement "That's why the 2 cycle engine should have a battery bank with twice the capacity of its 4 cycle counterpart". I understand the reasoning, but doubt the reality. Brian, you obviously have manuals for lots of equipment, for two stroke vs four stroke powered stuff, do the manuals validate this theory and in fact require twice the battery capacity?
The theory would also be validated if the buses that have changed from two stroke to four stroke engines have cut their battery requirement by 1/2. Has this really happened? |
Geoff (Geoff) (66.238.120.7)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 05, 2004 - 7:47 am: | |
Here is some reading on the 6.2, 6.5, and 6.6:
http://www.62-65-dieselpage.com/
I'm not discussing batteries anymore, we are beating a dead horse!
BTW, I have a service manual for the 6.2 industrial version published by Detroit Diesel.
--Geoff |
BrianMCI96A3 (69.34.169.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 05, 2004 - 8:43 am: | |
Don, I think I'll do a little research today and check some specs, I personally thihk that 2 stroke Detroits spin up easier than 4 strokes, but I'll see if I can back that up with solid info.
Geoff, I looked all over for that website yesterday,
seems plain that Detroit did build and design the 6.2 but it looks like AM General built the 6.2, and I surely believe Detroit Diesel wishes they hadn't built the 6.2
Brian |
DonTX/KS (66.82.9.47)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 05, 2004 - 8:53 am: | |
But Geoff! Beating dead horses is what this board does best, and this thread has risen to new heights (or depths). Just think, tomorrow's diesel engineers are being born before your very eyes. |
Tony (64.215.196.142)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 05, 2004 - 9:52 am: | |
and I bet they wish they didn't build the 8.2 either. I put them In the same catagory as the 3208 Cat, Junk
I wanted to compair the Cummins L10 with the Detroit Diesel and the place that I was talking to told me that the Starter on that Cummins has more power than that Detroit Diesel "grin" |
Phil Dumpster (24.16.189.48)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 06, 2004 - 9:18 pm: | |
Brian, while in theory the more compression strokes per revolution the faster the engine will start looks reasonable, it falls apart in practice. In my experience, given similar environmental conditions, a Series 60 and a factory 8V92TA will both start in the same amount of time. If the Series 60 has an "engine preheat system" it's no contest.
What your logic has failed to take into consideration, and what I believe makes the difference, is that quite a bit of air that makes it into the air box of the 2 cycle Detroit goes right through the engine without being involved in combustion at all. This air, especially when cold, can and probably does take away some of the heat that would normally remain in the engine block and head to help combustion start on the next compression stroke when starting the engine.
If you do not understand this, I suggest finding a Detroit Diesel service manual for the engine in question and looking at one of the cross-sectional illustrations. During the time when the exhaust valves are open and the intake ports are uncovered, compressed air from the roots blower goes right through the engine. This is called scavenging and according to the engineers who know more about this stuff than I do there is some great benefit to this. These days, they add plumbing to new engines to route some exhaust gasses back into the engine to reduce NOx emissions.
Your assertion that 2 cycle Detroits in good shape generally start on the first crank revolution is true for the normally aspirated engines, as they have high compression ratios and start very easily. Factory turbocharged engines have considerably lower compression ratios and unless it 60F or above, probably won't start on the first crank revolution. Recall the Ideal Gas Law from high school chemisty for the answer why this is so.
The 6V53TA DDEC has glow plugs because its compression ratio is so low that below 10F it won't start without some kind of thermal assistance. On the battlefield, you can't really expect to run an extension cord for a block heater and wait a few hours for the engine to warm up to starting temperature.
As far as spinning the engine before introducing fuel to ease starting, I do that on my MUI 6V92TA whenever it is colder than 40F out, as it keeps the smoke down. A quick shot of ether, about 10 revolutions of the crank, release the shutoff lever and it starts right away down to as cold as it gets around here. (mid 20s or so.) No big mushroom cloud of smoke. |
Johnny (63.159.125.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 06, 2004 - 10:43 pm: | |
"Johnny, the 8.2 is a 4-stroke, but it doesn't use glow plugs. The 6.2, 6.5 and 8.2 aren't boat anchors, they aren't bad engines, they just aren't designed to last as long or be as easily rebuilt as the bigger Detroits."
I had the misfortune to have a GMC K-35 4x4 with a 6.2 Detroit dumped on me. Even with a TH400 4.56 gears, it was the most gutless dog I've ever driven. It was actually dangerously slow when loaded. Of course, with the deep gears, it got an unimpressive 13-14MPG. I'd rather have a gas six cylinder. The 6.2/6.5 is one of the biggest turds ever crapped on an unsuspecting public; its crappiness matched only by the 260 & 350 Oldsmobile diesels. |
Johnny (63.159.125.82)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 06, 2004 - 10:46 pm: | |
"Firstly, Phil, having the engine spin any longer than it takes for the sensors to inform the computer where timing is on the engine, is a waste, plain and simple and I don't believe anyone will ever program an engine computer to behave in that fashion, ever."
Emissions. The hotter the chambers at startup, the less unburned fuel out the tailpipe. Also, many EFI engines crank without fuel 2-3 times for oil flow. |
BrianMCI96A3 (69.34.169.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 07, 2004 - 12:10 pm: | |
Johnny, while some electronically controlled engines indeed have sensors for oil pressure, NO engine turns over 2-3 times without oil flow!
Conversely, no engine cranks over 2 to three times simply to ESTABLISH that oil flow.
Hmmmmm, well Phil, since I'm a diesel mechanic of 25 years experience, I know quite well what a two stroke Detroit liner looks like AND how one functions inside the engine.
BUT, let's see if I've got this straight, first you say.
"Another reason why 4 cycle diesel engines take less power to start is because only half of the cylinders are on their compression strokes during a given engine revolution. Since this is the major component of the load on the starter, the more air you have to compress, the more energy it will take to start the engine"
Therefore your assertion is, two strokes use more energy to start, because they have TWICE the amount of compression strokes.
To which I replied, twice the compression strokes, twice the opportunity to fire.
But then you say that MY logic falls apart because...
"During the time when the exhaust valves are open and the intake ports are uncovered, compressed air from the roots blower goes right through the engine."
Hmmm, I see, so then I guess that's only HALF a compression stroke!
And if you follow THAT logic then it takes half the energy for half a compression stroke!
BUT, now we are stipulating only TURBOCHARGED two strokes below 60 degrees, right?
"The 8V92TA displaces around 736 cubic inches, distributed in 8 cylinders. On each revolution of the engine, all eight of these cylinders will have a compression stroke. This represents a compression load of 736 cubic inches."
"The Series 60 displaces around 762 cubic inches, distributed in 6 cylinders. On each revolution of the engine, three of these will have a compression stroke. This represents a compression load of 381 cubic inches."
But wait!
"During the time when the exhaust valves are open and the intake ports are uncovered, compressed air from the roots blower goes right through the engine."
...So, HALF a compression stroke, right?
Alright... that makes the loading on the two stroke starter half that of the 4 stroke...
But WAIT!
At half the loading wouldn't the engine spin faster, and therefore start faster?
AND...since two strokes have twice the compression strokes giving them twice the opportunity to fire ...oh wait, I forgot those pesky turbo's that lower the compression ratio so drastically.
Hmmm, so if you lower the compression ratio, aren't you lowering the load on the starter as well? So a two stroke with a turbo should spin faster still!
But wait!
Don't most modern 4 strokes ALSO have turbos?
Well lets see what other pronouncements, I take issue with.
"Without some kind of engine preheat system, you're going to use a lot of battery power cranking the engine until it gets hot enough to start."
REALLY, you mean the heat of compression just will not do it?
That's pretty strange when you consider that the VAST MAJORITY of heavy duty diesel engines have NO such preheating system.
But the statement I liked best is:
"Your assertion that 2 cycle Detroits in good shape generally start on the first crank revolution is true for the normally aspirated engines"
See, and I thought you wouldn't listen to reason!
Brian |
Don TX/KS (66.82.9.46)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 07, 2004 - 7:26 pm: | |
Ohhh, I just love it! |
Geoff (Geoff) (66.238.120.90)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 07, 2004 - 10:06 pm: | |
It don't really matter to me, all I know is more batteries are better. Yup.
(How's that Don??) |
DonTX/KS (66.82.9.15)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, February 07, 2004 - 10:33 pm: | |
I always figured that I HAD more and better. When I kicked in those 8 L16 Trojans for help after topping off the charge with the genset, I had enough battery to drive for a few blocks even if the fuel tank was dry! Any more and I would have had to give up a baggage bay to add another axle like some of the inferior buses did.. It seemed to me that if you could not run the AC all night from the inverter, you were short on batteries. |
Johnny (63.159.129.166)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 08, 2004 - 12:47 am: | |
"Conversely, no engine cranks over 2 to three times simply to ESTABLISH that oil flow."
Completely false. BMW engines have done just that for several years. Were I programming an EFI system (not liklely in the near future), I would do that.
I have to say that the 6V71 at work is REALLY unhappy starting below 20 degrees without ether. It starts, but I think the smoke cloud is visible on the Logan air traffic radar.
The best unassisted cold-starter I've ever seen was an International DT466. |
BrianMCI96A3 (69.34.169.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 08, 2004 - 9:48 am: | |
Johnny,
"Completely false. BMW engines have done just that for several years. Were I programming an EFI system (not liklely in the near future), I would do that."
So, what you are saying is BMW purposely spins their engine 2-3 times to simply establish oil flow?
YOU BETCHA!
Love to see the engineering study for that one...
I think you and SHOULD program EFI systems, you'd be great.
As far as starting batteries go, of course MORE IS MORE, that wasn't the argument... The argument was whether you can you get by with less, and the answer is: yes.
Brian |
Johnny (63.159.213.1)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 08, 2004 - 2:59 pm: | |
Yes, BMW engines crank without fuel several times to get oil flowing--which does strike me as a very good idea.
Heck, my Gremlin will get a rudimentary system that does the same thing: since it runs lots of initial timing (blower engine), this really strains the starter. So, I'm going to wire in an ignition-cutoff button for easier starting. I'll crank it 3-4 times without the ignition to get oil flowing.
"I think you and SHOULD program EFI systems, you'd be great."
Huh? A minute ago you claimed no engine cranks several times to establish oil flow...now it looks like you're saying the opposite. |
BrianMCI96A3 (69.34.169.42)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 08, 2004 - 4:58 pm: | |
Well, I figured you'd understand sarcasm Johnny.
I see that 2-3 times isn't good enough cranking for that Gremlin of yours (blower engine)... 3-4 is much better I agree, or maybe 4-5, or a half... no a FULL dozen even!
But, GEE why not save all that battery power and use a hand pump to get that ol' oil flowin?
I'd still love to see that engineering study.
Brian |
Johnny (63.159.213.238)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 08, 2004 - 6:59 pm: | |
Unfortunately, sarcasm in text doesn't come across well.
From experience, the ignition cutout on the Grem is required, unless I swap to an ignition system with a cranking-retard system (which my mid-80's-vintage MSD lacks). Since that is pricey and I'm both broke and cheap, I'll go with the button. Starting it hot right now is almost impossible, even with my big (1050CCA) battery.
The way I see it, it would be easier on an engine to turn at 150RPM than at 950 to get oil flowing on a cold startup.
If you really want to ensure a cold-start has plenty of oil flow, just plumb in an accumulator with a 12V solenoid on the hose. Turn the key on and you instantly have pressurized oil flowing to the engine. The Grem may get this, especially if I am able to do the open-track events I hope to. |
BrianMCI96A3 (69.68.96.122)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 08, 2004 - 9:01 pm: | |
I disagree, I think sarcasm done properly comes across just fine in text.
For instance I could say something like:
What is the "....12V solenoid on the hose..." for? Is there a bendix drive on the hose that it's attached to??
That's kinda sarcastic.
But I won't say that, because I actually think an accumulator with a normally closed solenoid VALVE on it, (so that when the key is off it closes and retains oil pressure)is a really good idea.
It's a superlative idea when compared to cranking the engine over a bunch of times.
While I will not argue that building oil pressure at 150 rpm is easier on the engine than running it, the fact is, NOT RUNNING the engine, just spinning it, is always easier on the engine, a lot harder on the starter though.
What you do not realize is how quickly oil begins to flow (almost immediately) and how fast an engine builds pressure(shortly there-after).
MANY(if not all) electronically controlled engines will not start unless oil pressure is sensed, and under normal conditions that is almost immediately after the engine begins to spin.
The ONLY reason an engine spins more than a revolution before starting, under normal circumstances, is NOT to start oil flow or establish that flow, it is for the cam sensor and crank sensor to determine engine timing for the computer... By that time oil pressure has already reached a level sufficient to safely start the engine.
About the only other normally occuring instance where the engine will not start on the first revolution, after timing is determined, is after an oil change.
Then, the oil pump needs to siphon oil up from the pan before it will begin to build pressure (unless you didn't fill the filter, then it will take longer still) and even that extreme situation will take just 3-4 revolutions.
And Johnny, try to remember that older engines without electronic controls often run after an oil change, for a second or two with NO oil pressure at all, and that will happen dozens of times in the life the engine, with little or no effect on the engine!
Though I'm not familiar with the requirements of open track racing, I will say that while your accumulator idea has great merit, especially for a high performance engine...the REASON your engine is difficult to start from a dead stop is it's high performance nature, it's compression, COMBINED with combustion, not lack of oil pressure.
The starter you are using just was not designed for the load you are putting on it.
SO the reason for the ignition cut-off is to get the rotating mass of the engine spinning WITHOUT combustion.
THEN, with your finger off the cut-out, the inertia of the rotating mass is COMBINED with the starter and is enough to overcome the added load of combustion to start your engine.
Work on getting that accumulator idea going though, a supercharged engine with full oil pressure at key on certainly can't hurt.
Brian |
Johnny (63.159.128.148)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 09, 2004 - 4:49 am: | |
Actually, the compression on my Grem's 401 is rather low (8.5:1)--but the advanced timing makes hot-starting very difficult.
Open-track events involve high lateral G forces, which can easily uncover the oil pickup, even with a baffled pan. An accumulator is much cheaper than a dry sump.
When I change oil, I disconnect the ignition (or pull the fuel pump fuse if it's EFI) & crank until I have oil pressure.
"The ONLY reason an engine spins more than a revolution before starting, under normal circumstances, is NOT to start oil flow or establish that flow, it is for the cam sensor and crank sensor to determine engine timing for the computer."
You are wrong. Period. I am 100% sure on this. BMW engines spin at least 2-3 times (might be four) before firing to ensure sufficient oil flow. |
Peter Broadribb (Madbrit) (67.136.121.168)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 09, 2004 - 8:07 am: | |
Johnny,
I had the same problem with my 427 powered '55 Chevy wagon. Ended up just adding a seperate push-button connected to the starter so I could spin the motor and when it was going, then turn the ignition key on. I did have the starting retard system on my MSD 7 AL2, but it didn't seem to help much. Of course, Chevys always had that hot start problem and I was even running the late Chevy mini starter they put on the big blocks, obviously didn't like the 12.5:1 compression and all that advance the motor liked........ LOL.
Btw, want to buy the motor, has less than 150 miles on it, aluminum heads and all.
Peter. |
BrianMCI96A3 (69.68.96.122)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 09, 2004 - 8:28 am: | |
Johnny, you'll note that I did not mention HIGH compression in my previous post, since it is a supercharged engine AND I didn't want to get into explaining high/low compression and timing.
SO the reason for the ignition cut-off is to get the rotating mass of the engine spinning WITHOUT combustion.
THEN, with your finger off the cut-out, the inertia of the rotating mass is COMBINED with the starter and is enough to overcome the added load of combustion to start your engine.
What about that doesn't get it for you?
(sarcasm)
You think I'm making all of it up right out the clear blue?
Brian |
BrianMCI96A3 (198.81.26.45)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 09, 2004 - 3:07 pm: | |
So... because I could not believe any engine manufacturer in their right mind would spin their engines 2-3 times to establish oil flow (absurd) before starting, I called...
Desert BMW of Henderson (702)257-1010 and spoke to Dale in their service department.
I explained to him the nature of our discussion and gave him this synopsis of the argument.
While some electronically controlled engines have sensors for oil pressure, no engine turns over 2-3 times just to establish oil flow.
VS.
Completely false. Bmw engines have done just that for several years. Bmw's engines crank several times without fuel to get oil flowing
Having heard this, the first words out of Dale's mouth were...
"No, BMW engines start dry."
He went on to explain that BMW engines do not utilize a sensor for oil pressure to enable or disable engine start-up.
They do have a sensor for oil level, which is pulsed a current and heated, the rate at which it cools determines the oil level... they had problems with it in the past, which caused a no start situation when they failed... but that is the only sensor for the oil.
There is no oil sensor for the computer to determine start/no start conditions.
Thank you, thank you very much!
Brian
And NOW heeeerrrrees's Johnny!
Brian |
Phil Dumpster (24.16.189.48)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 10, 2004 - 3:38 am: | |
Brian, had I know you were this hypersensitive to reality I would not have bothered to try to explain to you why you should use the same size batteries in your bus that the engineers specified be there, which if you care to look back is the original purpose of this thread.
Watching your interaction with Johnny, I'm torn by feelings of amusement and sympathy. Amusing that you seem to be getting so worked up over something so insignificant, as if your life depended on ramming your opinion down everyone elses throat, and sympathy that you have the sort of personality that radiates from someone with a virtually non-existant sense of self-worth.
I'm not even going to attempt to dignify your arguement with any kind of counter-arguement, as there is no use. Your irrational rambling about "half a compression stroke" (I'm still trying to figure out where THAT came from) proves that you'll make up your own logic to suit you as you see fit for any occasion. Without a common frame of reference (i.e. reality) any kind of discourse with you is destined to end up like Monty Python's Arguement Clinic sketch. ("No, it isn't!" "Yes, it is!" "No, it isn't!" "Yes, it is!" "No, it isn't!" "Yes, it is!")
Do yourself a favor, save up some of your money, see a truly world class psychiatrist. They can help you transform yourself from an emotional child to a mature and reasonable adult.
In the meantime, stop driving 15 ton busses around. I'd hate to see how you would behave behind the wheel. |
DonTX/KS (66.82.9.35)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 10, 2004 - 8:42 am: | |
My goodness! Personal attacks and a psychiatrist diagnostic in one post! I thought this board was more inclined towards opinions and rational discussions |
BrianMCI96A3 (65.40.153.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 10, 2004 - 3:57 pm: | |
"Brian, had I know you were this hypersensitive to reality I would not have bothered to try to explain to you why you should use the same size batteries in your bus that the engineers specified be there, which if you care to look back is the original purpose of this thread."
Ahh, Phil... the pomposity of your words leaves me breathless. You are a true maestro of the meaningless blather.
Had I realized the degree to which you IGNORE rational thought in an attempt to force the world into alignment with your narrow perceptions, I would have treated you much kinder in the past, forgive me.
I will try to be more compassionate towards your ego from now on...
I am sorry that you feel unable, or ill equipped, to continue the debate.
The engineers, as you are so fond of iterating, did indeed stipulate large batteries for our coaches...
In the case of my 96A3, if one were to dissect the original design parameters, one would see that their (the engineers) choices for the charging system were predicated on the design platform's use as an OTR coach, hauling 40 to 50 passengers and their luggage...perhaps some freight, over long distances, with enough air conditioning, heating, lights and in the case of my coach, coffee-making ability, for everyone's comfort... at all times...including long stretches of idling time.
These design parameters specified the use of a 275 amp alternator and two 8D batteries.
Let's now shift the design parameters, remove the 40-50 people and their attendant luggage (AND their body heat), remove the huge load associated with the air conditioning, including fans, blowers and a/c clutch, remove the a/c compresor, the condenser, and evaporator.
Remove the seats and luggage racks with their numerous lights and squirrel cages.
Remove the destination sign.
Remove the 1500 watt motor driven inverter for the coffee maker.
Eliminate the long idling time under heavy load.
Eliminate virtually everything electrical associated with making this an OTR coach.
What you are left with, essentially, is an eight wheeled enclosed truck.
Taking the design parameters for a ten wheeled heavy-duty truck of similar weight, similar electrical loading with an identical engine, the engineers specified the use of two group 31's and a 120 amp alternator.
Please note that this post...
"There certainly is nothing wrong with using 8D's in your conversion, or using a pair of 4D's, or FOUR group 31's... but a pair of WELL MAINTAINED
group 31's used merely as starter batteries are adequate to the task."
...occured about a third of the way down the thread.
And this post...
"As far as starting batteries go, of course MORE IS MORE, that wasn't the argument... The argument was whether you can get by with less, and the answer is: yes."
...occured more than three quarters of the way down the thread.
Because...
You, trying to explain to me, why you THINK I should use the same size batteries in my bus that the engineers specified be there, is NOT the original purpose of this thread.
I guess you didn't look.
The idea of using just what the engineers originally specified, without taking into account changing design parameters....well, in this case it is an easy, safe and perhaps even a worry free choice.
Do what makes you happy Phil, by all means.
Those not so short sighted, will understand that I'm not trying to impose my opinion.
To the contrary, they can do what makes THEM happy.
I'm am merely trying to point out that simple-mindedly following the engineering specs while ignoring the fact that the design has changed enormously, isn't the only way.
Based on the observed history of dozens of heavy duty vehicles, not blind faith, two group 31's will give years of service as starter batteries for a Detroit Diesel.
As for irrational ramblings that have no basis in the real world, I believe you are the king in that arena...your thought processes tend to remind me of Monty Python's Spam sketch (i.e."Spam, spam, eggs, spam, sausage and spam." ).
In other words: The pronouncements you have made on this thread thus far, have some minor air of logic to them, but mostly they sound like alot of spam.
Perhaps you are right, I am, as you say, "hypersensitive to reality", as I simply cannot stand misinformation from the uninformed, or faulty logic which, in the real world, does not fit the observed facts.
I find it instructive that you feel the need to preserve dignity on the one hand, (boldly chosing the better part of valour), while on the other, feeling perfectly dignified in making all sorts of
personal attacks upon my character.
As for my driving, I first obtained a Class A liscense, back when it was called a Class 1...over 20 years ago, I couldn't possibly count the number of heavy duty trucks of all types, that I have driven over the years... By PROFESSION; I am a diesel mechanic with a quarter of a century experience (by coincidence; I am a Busnut).
I do not know YOUR qualifications OR your profession
...say, you aren't by chance the former Information Minister for Iraq, are you??
Brian |
Phil Dumpster (24.16.189.48)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 10, 2004 - 9:56 pm: | |
Thank you, Brian, for thoroughly validating everything I wrote in my previous post. |
BrianMCI96A3 (65.40.153.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 11, 2004 - 1:07 am: | |
Poor Phil, still tilting at windmills, I see.
Brian |
Geoff (66.238.120.160)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 11, 2004 - 10:03 pm: | |
Don-- don't trucks use 2ea 8D's or 4ea Grp 31's? I am confused.
--Geoff |
DonTX/KS (66.82.9.33)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 11, 2004 - 11:14 pm: | |
Geoff, I never seen one, they might though. As I had said, my 3406 Cat powered KW W900L came with two group 31's (12v system) A relative that is fleet maint chief for over 250 big trucks (Nevada Ready Mix, Las Vegas) says no 8d trucks ever for them (Most all Petes and Kenworths) Some of theirs originally came with 3 group 31's 600 amp), they instantly change to two 925 amp. Their experience is that three or four batteries cause much more trouble than two in the long haul, due to more connections to fail, and one bad battery sucking down the rest. Two (I think he said 925 amp or bigger) exceed all the manufacturers requirements and is their choice of battery power.
Of course I realize, Las Vegas is not the coldest spot on the earth too. I challenged board members to check to see what their bus manual said about betteries, nobody responded. I know the GMC 4905 NEVER said anything about Group 8D, only that the two batteries should be 900 amp each or thereabouts. Group number has more to do with size than capacity directly. |
BrianMCI96A3 (65.40.153.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, February 12, 2004 - 12:14 am: | |
Although part of our fleet of trucks is based in Las Vegas, the purchasing authority for the State of Nevada is located in the North...Carson City being the capital, and Reno, a much colder climate, is where all our trucks are acquisitioned.
A large number of our trucks and equipment are spread through-out the state, many in very cold climates such as Mt. Charleston, Mt. Rose, and Lake Tahoe, Elko, most of those trucks use two Group 31's (as do many pieces of road working equipment) I do not believe any of our trucks use 8D's.
Some, very few actually, use a pair of 4D's.
Brian |
william edgar (Honkytonk1) (216.96.18.5)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 18, 2004 - 9:20 pm: | |
I went ahead and picked up 2 group 31 12 volt batteries and installed them yesterday. They turn the 8V-71 every bit as fast as the 8D's did. Bigger isn't always better. Oh yeah, it was about 28 degrees and she took right off. WC |
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