| Author | Message | ||
| Justin Dortignac (4.47.31.103)
Rating: N/A |
Hey, We bought a 1990 National Coach 31' DP with a Detroit/GM 8.2L T.C. Allison 643 Empty wt. aprox. 21,000lbs. 188kMi. The bus is SLOOW any decent hill drops us to 20mph/1st gear. bus dynod 88HP Considering the weight of the bus we (think) would like to repower it. The problem, endless questions. What engine's will fit? How big is needed, is a 8V92(probly won't fit) too much? Should we only consider Detroit? Transmission...will the current one match/be big enough? Where can we take it to have this kind of stuff done(We're in So. Cal)? Will we have to consider the cooling system? Would appreciate any answers/opinions on this topic. Thanks Justin Dortignac 3of14 | ||
| Tom Caffrey (Pvcces) (65.74.66.104)
Rating: N/A |
I can't help thinking that you might be better off trying to boost that horsepower in the same engine. Some of these are rated for quite a bit more power. For what it's worth. Tom Caffrey PD 4106-2576 Suncatcher | ||
| Thunder Coach Ron (64.12.116.135)
Rating: N/A |
I think you should look at boosting the Horsepower!...It may be that the RPM's is not turning the wheels...Also the regearing of the rear end...repowering is costly $$$ Where is the engine in your Bus? Ron "Crown are the Best" | ||
| TWO DOGS (63.185.72.32) Rating: N/A |
you don't say where you are on the conversion...if you haven't started the conversion yet...get a different bus...with a bigger engine | ||
| Justin Dortignac (4.47.31.103)
Rating: N/A |
Thank you for your response. The engine nameplate says it's rated at 225HP the bus Manual says 205HP Detroit suggested that it needed a rebuild. The engine is in the rear. The bus is already converted, and we're pretty stuck on it so far. We like it alot because it's only 31' long, we can park it at our house, and it's built like a intercity... Large understorage, 11'6" Ht... I believe it is geared for highway although I will check it again this afternoon. We are aware that repowering is expensive and are ready to invest what it takes(?). | ||
| Bruce Henderson (Oonrahnjay) (209.247.222.81)
Rating: N/A |
__. OK, it's rated at 225/205 HP but it dyno's to 88 HP. That pretty well tells me that the engine is shot - you gotta do something; either rebuild or reengine. It's pretty much a bang-for-the-buck question, isn't it? Bruce Henderson, Wallace NC | ||
| guy bouchard (161.184.178.237) Rating: N/A |
Your first option would be to find out if your engine is tuned properly. You would be amazed at how many shade tree Detroit mechanics attempt a tune-up with very little knowledge about the governor adjustments and timing adjustments. We've seen some of these come thru that were out by a 1/4 of an inch; never mind a few thousands. Although the 8.2 never got the same respect as the 2-cycle Detroit, you have to remember that it was a light duty diesel, and performed well as long as it lived. It could be that it is worn out as you mentioned, but a tune-up on an 8.2 is more tricky than on a 2 cycle. Guy 4905 | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
Yeah, two things here. The first is like others more experienced has already said, only 88 hp at the road does seem kinda weak. The 8.2 liter 500 inch V8 Detroit 4 stroke has unit injectors. This means that a mechanic must "run the rack" kinda like... ...the same on a 2-stroke. If things are not correct, the mill will run, but badly. Does it use oil? Does it blow smoke? Maybe all you need is a good tune up, then retry the dyno test. You should be seeing between 125 and 150 road hp on a cool day. The second thing is that the mill is just worn out. Try the various searches for a good used 8.2 Turbo take out mill. They are still... ...available and somewhat cheap, but most of them have been consigned to use as boat anchors and such. Might however, be able to find one. If you decide to rebuild your mill, or have it done, do not be afraid of making a few changes to the thing. Going to bigger injectors, opening... ...up the intake and exhaust systems, bumping the governor, etc,, in your application with low annual miles you will not wear the thing out. In marine applications, the 8.2 did a fair job. With a few hop ups, you can turn your coach around from a slug to a winner. Good luck. | ||
| Justin Dortignac (4.47.31.103)
Rating: N/A |
This is good, I'm enjoying all the input and I'm learning alot. Keep it coming Will consider the tune up although we just took it to ABC Bus Service and they thought that our only problem was a spring on the gonvner which they replaced telling us "You'll definatly notice the difference". Well, needless to say there was no noticeable difference. Give it to me straight... is an attempt to repower rediculus? How would I know if it's even feasible? In answer to your questions: It does blow white smoke, but only at a high RPM in neutral. It blows little to none when actually driving. I haven't noticed any excessive oil loss but we've only driven it about 2k Mi. | ||
| Gary McFarland (Gearheadgary) (209.128.79.46)
Rating: N/A |
I can't speak to your particular application, but in general, repowering is hard, and to be avoided. If Henry's advice is accurate, I'd follow it. On the other hand, I believe a 3208 Cat will bolt up to your MT643. that should bring Two Dogs out of the woodwork. Gary | ||
| TWO DOGS (63.185.80.1) Rating: N/A |
yeah ..it did...naaaaa... if you are going to repower,need to think about something with some balls...6 cylinders out of big trucks...almost all of them are 700+ cubic inches | ||
| TWO DOGS (63.185.80.1) Rating: N/A |
you can buy a good wrecked big truck for 5000,& use engine. radiator ,computer....many many parts...will have to talk to somebody else about the automatic tho | ||
| Gary McFarland (Gearheadgary) (209.128.79.46)
Rating: N/A |
Yeah, while a 3208 is only 636 cubes, and bolts right up to the MT643. Standard turbo is 250 HP, 275 with intercooler, and that's in "Detuned" motorhome flavor. I know of 3208s turning over 450HP, but they make heat. If you do decide to repower, get a lot of real information, all you're getting from Two Dogs and me are opinions. Gary | ||
| jimmci9 (209.240.205.68) Rating: N/A |
as far as a repowering, unless you really want a lot of retrofit headaches, stick with something the same size... the cat 3208, detroit's 6v53 (a 2-stroke), ihc's 7.3 liter are within inches and pounds of being a replacement....there are lots of the 7.3 ihc engines out there.. and the powerstroke ford diesel is just a later/electronic model of the 7.3...all will work with your allison... depending on hp and available rpm's, the torque convertor might need some help... | ||
| Gary McFarland (Gearheadgary) (68.252.126.82)
Rating: N/A |
Jim, what is the 8.2, I'm curious, I don't know anything about it. Should he get another one? or is it just a dog? Gary | ||
| Thunder Coach Ron (198.81.26.45)
Rating: N/A |
Allison will go to almost all engines...they stock the ring gear...bell houseing's...used is good...new is costly...frt is cheap...8.2 is old...I belive when repowering go all the way with power that will fit..look for a newer engine thur a truck wrecking yard...just a note...Its a big ???? Ron Thunder Coach "Crown are the Best" | ||
| madbrit (67.136.84.54) Rating: N/A |
The 8.2 is a dog, better find a newer more powerful engine/trans. My neighbor's best buddy has a Country Coach with the 8.2 Turbo and it can't get out of its own way....... LOL. Peter. | ||
| Johnny (4.174.103.26) Rating: N/A |
The 8.2 is a boat anchor--it's almost as bad as the 6.2 litre pickup truck engine. I suggest, if it will bolt to the tranny, a 5.9 litre Cummins 6BT or, if you have plenty of money, a Cummins ISB. Plenty of power (there are dozens running 500+HP), stupendously durable (there are 150,000+ mile ISB's running 800+HP on an UNTOUCHED bottom end), has a pretty good fuel burn, & will be perfectly happy toting your bus. | ||
| Gary McFarland (Gearheadgary) (209.128.79.46)
Rating: N/A |
"Allison will go to almost all engines" There is an Allison for almost all engines, but the 643, I an SAE type 2 bellhousing, where the bigger iron, like the Detroit is a type 1 (Right?) I believe these fit an HT type trans. I'm new to this end of things so someone correct me if I'm wrong. "The 8.2 is a boat anchor--it's almost as bad as the 6.2 litre pickup truck engine" Ouch. Maybe you should look at a Cat, if you go the the E-Place and search for 3208 CAT you will see a guy that is selling factroy remans for $5,750. I would strongly advise against buying an engine with an unknown history. Good luck, Gary | ||
| Henry R. Bergman, Jr. (Henryofcj) (63.224.197.10)
Rating: N/A |
Hello again. Finally something I may be able to help with. The 500 inch 8.2 liter Detroit V8 4 stroke is actually a very compact mill. They were designed to be able to be swapped out with 427 tall block GMC V8 gas engines within 2 ton trucks. We actually stuck one into... ...a 1 ton Ford farm truck years ago. Fit easily considering. It was a non turboed version with none of the extra stuff on top of the mill. The point being that since the Detroit 8.2 is fairly compact, finding another likey replacement diesel will be very difficult. You may not have the physical space in your mill compartment to repower with something more recent or desirable. Specifically, a 6V53 Detroit... ...would most likely not fit. The 6V53 is kinda big and heavy. The 8.2 turbo mill only weights about 1300 pounds or sooss. Quite light. Sossss, what to do? With my compliments to the dealer you went to, if they say the mill is in fair shape and does not require a tune up?... ...but only puts out 88 road hp, AND seems not to use hordes of oil, and does not blow smoke..and seems to have good compression... ...then something seems not right. Should run better than what it is doing. Anyway...try another good Detroit shop who knows what... ...they are doing?...and understands the 8.2 Detroit? May be cheap money spent finding out what exactly is wrong with your present engine. THEN...once you know what you have, then explore the possibility of doing one of two things. The first is finding a dyno tested, warranted, used... ...8.2 Detroit turbo mill and doing an engine change. May be cheapest to do this. However, be advised that the odds of finding a good engine... ...getting it installed and not being ripped off along the way are only about fifty fifty. The other thing to do is to pull your present ... ...mill and having it rebuilt. $Ouch$. But... you can have the builder build it your way. One can go easily to 250 hp with this engine. ...and 300 hp is not impossible with N75 injectors, and a turbo swap, along with bumping the governor up to 3000 rpm. Or...you can cut and run and sell the coach as is, where is, and find something else for your needs. The choice is yours. Detroits Forever!! | ||
| jimmci9 (209.240.205.60) Rating: N/A |
ive seen several of the "trolley' looking city transits that are 30' long that are powered with the 8.2... kinda hard to work on, but better than a c-60 chevy truck, as fas as acess is concerned... injectors and governor are very similar to the 2-strokes detroit made, but the injectors set with a dial indicator, instead of using a timing pin, therfore, lots mor difficulty... without going into lots of detail, they have different measurements, fron injector to injector, with the individual setting written on the valve cover...there is a default setting, and lots of mechanics used it... the 8.2 was detroits "foot in the water" as far as 4 stroke stuff goes.. and bombed as far as popularity... it had competetion from cat's 3208... ihc's 9.0 liter... and ihc's dt466...lots of "city dump trucks" were powered with the 8.2 and the texas highway dept. bought quite a few... there ought to be quite a few of them in salvage yards... ive seen several cores in our company's core pile... i vote for a repower with a cat 3208.... i think the 5.9 cummins will be too long to fit where your 8.2 is now.... | ||
| Justin Dortignac (4.47.31.103)
Rating: |
Wow! Thank you for your help so far. We now have alot to think about! How do I know if one engine or another will fit? Does anyone know of a good shop that works on buses in/near Southern California? And Can anyone explain to me the difference between "Right hand drive" and "Left hand drive"(Clockwise/counterclockwise rotation) engines? | ||
| Tom Caffrey (Pvcces) (65.74.66.104)
Rating: N/A |
Justin, left hand drive engines set in the bus crosswise and drive the rear axle through a vee drive transmission. Right hand engines set in the bus fore and aft and use a straight transmission to drive the rear axle. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher | ||
| Henry R. Bergman, Jr. (Henryofcj) (67.136.241.239)
Rating: N/A |
Sorry I am hogging the bad answers. Understand your concerns and needs. You need to get your coach running properly. A real bummer creeping up hills. Measure your engine compartment with a tape measure. Width, length and height. Might just be possible/probable that another mill may fit. Sometimes RV factories left in extra space for optional engine selections. Might be true in your case. About the only other diesel mill... ...that may fit physically in your coach would be the excellent Cat 3208T V8 4 stroke. Good mill for its time. Tried and true and stuff. About 1650 pounds with the turbo and a lot bigger physically than the 8.2 Detroit. Like already said before, also 634 cubic inches. You do have an excellent Allision tranny. The 643 is a 4 speed with a lock up clutch. Will handle the 3208T in my opinion. Your Allsion... ...PROBABLY has the #1 housing. I do not know if the torque convertor would work with the 3208, but most likely MAY. Some other... ...opinions here please. My info very dated as am I. Anyway, the 3208 Cat may be an option. Be advised it would be a LOT of work getting... ...it to fit. Probably much $more$ than the cost of the Cat. Just about all the support systems of the mill will have to be changed out. This would include mounts, cooling, exhaust, intake, wiring, throttle, suspension, torque converter(?) etc.. Get the idea? $ouch$. In 2 ton truck service, the 8.2T seemed to last at least 200,000 miles with reasonable care. If you go to an exchange 8.2, try to find the... ...latest model/version/serial number possible. The later 8.2T mills had many improvments that made it a better mill. Perhaps someone will... ...clarify. There must be someone in the LA area (my old home town) that really understands the lonesome 8.2T Detroit and can tune you up. Good luck. | ||
| Gary Carter (68.25.26.242) Rating: N/A |
And don't forget the 7.3 binder engine used in the Ford PU. Easy to get over 300hp and about the same physical size as the 8.2DD. Also available used. | ||
| TWO DOGS (65.179.208.124) Rating: N/A |
yeah...7.3(t) better than a 3208t....just make sure it'a turbo | ||
| Gary McFarland (Gearheadgary) (209.128.79.46)
Rating: N/A |
"The 643 is a 4 speed with a lock up clutch. Will handle the 3208T in my opinion." Not opinion, fact. Jim can answer the torque converter and radiator questions, but I think you need to include the flex-plate from the cat. Wiring: One wire Exhaust: one pipe, can be built from walker parts available from Napa. Doesn't need a muffler. Throttle: get air if you don't already have one, but you probably do, since the MT643 needs a modulator signal, and as far as I know Diesels do it with air. Mounts: Get a cradle, I know where there WERE two, I can check if they're still there. I can definitely get you pics and measurements from mine if you need. I worked only with one ford/int 7.3, but that's because it shook worse than a dog shittin' razor blades. and the owner swore he'd never have another one. Carried a handful of grade-8 bolts in the glove-box to replace the alternator bolt that kept snapping off. If the alternative is THAT engine, yer 88HP 8.2 be lookin' mighty fine to me. Gary | ||
| Justin Dortignac (4.47.28.52)
Rating: N/A |
I would definatly be interested in dimensions. The numbers I've found on the web so far seem to be inaccurate. BTW our diff. is a 4.63:1...is that good or bad? | ||
| TWO DOGS (63.185.72.29) Rating: N/A |
bad | ||
| Marc Bourget (209.142.38.81) Rating: N/A |
Gary, If the 7.3 kept breaking Grade 8 bolts, was the alternator missing an additional support bracket? Gosh, after a couple of times, I be lookin' to how I could add one! FWIW Ever find a fix and what was the solution? Marc Bourget | ||
| TWO DOGS (65.177.144.102) Rating: N/A |
IF ya' keep doing the same thing...why would you expect different results....... ~DR. PHIL~ | ||
| Gary McFarland (Gearheadgary) (209.128.79.46)
Rating: N/A |
It was a brand new ford truck, they kept replacing the bolts under warranty, but they didn't always break in front of the ford dealership. they kept spare bolts and tools in the glove box so that they could replace then while on the side of the freeway. He was not a happy boy. Gary | ||
| TWO DOGS (63.185.80.152) Rating: N/A |
no ford guy is....no 3208 guy is either...they will argue with a fence post..  | ||
| Johnny (4.174.109.138) Rating: N/A |
"The point being that since the Detroit 8.2 is fairly compact, finding another likey replacement diesel will be very difficult." One reason I suggested a B-series Cummins. "THEN...once you know what you have, then explore the possibility of doing one of two things. The first is finding a dyno tested, warranted, used... ...8.2 Detroit turbo mill and doing an engine change. May be cheapest to do this. However, be advised that the odds of finding a good engine..." Are nil with an 8.2 Detroit, since all were turds the moment they came out of the factory. A B-series Cummins is loafing at 300HP (and barely breaking a sweat at 500). An 8.2 is basically maxed out at 300HP. | ||
| Johnny (4.174.109.138) Rating: N/A |
"And don't forget the 7.3 binder engine used in the Ford PU. Easy to get over 300hp and about the same physical size as the 8.2DD. Also available used." And a very good choice--the 7.3 IDI (NOT the electronic PowerStroke) is a very difficult engine to break--mine (1992 F-350, dealer-installed turbo) has 358,000 miles, my friend has one in a Ford E-350 cutaway bus running perfectly with a stunning 23,000 hours, & we have a 1986 Ford wrecker at work with 537,000 miles on an unrebuilt 6.9 diesel (smaller-bore version of the 7.3). "I worked only with one ford/int 7.3, but that's because it shook worse than a dog shittin' razor blades. and the owner swore he'd never have another one. Carried a handful of grade-8 bolts in the glove-box to replace the alternator bolt that kept snapping off. If the alternative is THAT engine, yer 88HP 8.2 be lookin' mighty fine to me." That engine had something wrong with it--probably firing on 7 cylinders. All 3 IDI's I deal with regularly run smoothly (though hardly quietly) from idle to 3000RPM (governor). The later PowerStroke, though a bit noisier, is smoother. And even the non-turbo 6.9 in the wrecker will easily gross 20,000lbs without drama. | ||
| Tom Caffrey (Pvcces) (65.74.66.104)
Rating: N/A |
IIRC, there was a modification to those engines that involved replacing all the head bolts with larger ones. We have one with the modification in front of an Allison in a bucket truck. I was surprised at the power of ours, so I think yours needs servicing, Justin. I believe that our truck might weigh right up near what your motorhome does. From what I've seen of this truck, I would not want to try a repower in it because of lack of room, especially on the sides. For what it's worth. Tom Caffrey PD4106-2576 Suncatcher | ||
| BrianMCI96A3 (67.77.37.160) Rating: N/A |
"...May be cheapest to do this. However, be advised that the odds of finding a good engine are nil with an 8.2 Detroit, since all were turds the moment they came out of the factory. " Well, having 25 years of experience as diesel mechanic I've seen a lot of engines fail and the 8.2 is no exception. Early on there was an excessive failure rate with even brand new 8.2 engines. Having said that, I can safely say that over the last twenty years no engine has been as reliable in our fleet of hundreds of vehicles...of all types. Our fleet has included as many as a couple dozen Athey street sweepers with the 8.2 over the years. These vehicles run in the worst of conditions, in the dust and mud, at low speeds with the engine running at high rpms. Amazingly enough, in the last 17 years we have had NO engine trouble with the 8.2 powered sweepers, in fact the only work that has needed to be done on any of those engines, besides alternators, was a fuel transfer pump needed to be replaced on one... I'm not saying the 8.2 is endowed with mystical powers, but as far as I'm concerned, it's not the boat anchor many make it out to be. As for power an 8.2 in good condition ought to handle a 31' bus easily, perhaps not as well as some others mentioned here, but well enough. The 8.2 isn't a beauty queen, but I think it deserves a better rep than the one it has gotten. Brian | ||
| Johnny (4.174.109.119) Rating: N/A |
I have NEVER heard ANYTHING good about the 8.2 Detroit beyond "they're cheap to replace when they let go". Everything I've heard seems to be that the NA engines are (barely) acceptable if you really baby them, the turbos are hand grenades, & none have enough grunt. I know several people who would choose a 366 or 427 gas engine every time over an 8.2 in an MDT. With the possible exception of the 9.0 litre International, I've never heard such universal scorn for any other truck engine. | ||
| BrianMCI96A3 (67.77.37.160) Rating: N/A |
Well, there you go, I suppose it really all depends on what you are used to... But like I said, the 8.2 is the only engine we haven't had to replace in the last 17 years, in a fleet of hundreds of vehicles. And in street sweepers to boot... Athey stuck a 6.5 (now the turbo'd 6.5 is a hand grenade, and the n/a 6.2 is barely adequate) in their M-8 Patriot sweeper a few years back and we had to replace the engine in it three times in three years, finally convinced the paper pushers that it was junk, and got rid of it. But we still have a few of the 8.2 units out sweeping even though most of them are over twelve years old now Perhaps in the trucks you've seen them in they were abused and overloaded, but considering Justin's 31' National Coach is a 1990, I'd say the 8.2 in it lasted quite a long time. I think the biggest argument for replacing the 8.2 Justin has with another 8.2 is: With only 88hp on the dyno Justin's 8.2 will actually STILL push his coach up a hill at all... nevermind at 20mph. Brian | ||
| BrianMCI96A3 (67.77.37.160) Rating: N/A |
Or rather, the biggest argument AFTER the pain in the A** it is to retrofit almost any powerplant Brian | ||
| Johnny (4.174.106.98) Rating: N/A |
The street sweeper might be why the boat anchors have lasted: they're probably a very low power rating (I'd be stunned to see 200HP), a low RPM governor setting, with an automatic tranny that are rarely heavily loaded. You'll have a hard time convincing me that a C-60 that never carried anything heavier than laundry was overloaded. It ate 2 8.2 Detroits (the original & a factory reman) in the space of 120,000 miles. They put in a take-out (from a burned GMC school bus), sold the truck, & bought an F-600 with a 5.9 Cummins. MUCH better--and they still have it after something like 450,000 miles. | ||
| BrianMCI96A3 (67.77.37.160) Rating: N/A |
I've seen some pretty abusive laundry companies here in Vegas, Mission Linen for one is really unkind to their trucks... It could be that a street sweeper is the perfect application for the 8.2, but depending on the miles, 14 or 15 years in Justin's coach isn't so bad, and perhaps his 31' application isn't so bad for an 8.2 either. Brian | ||
| Johnny (4.174.106.76) Rating: N/A |
I know the driver--he doesn't abuse the truck. |
