| Author | Message | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 130 Registered: 11-2008 Posted From: 70.52.103.117  Rating: N/A |
I'm beating your ears, I know, but I've got a lot of questions.And a lot of the answers aren't in DA Book. Now, I'm no great shakes as a driver so I make mistakes. I miss gears, leave it in a lower gear (longer than I probably should) when I know a hill (or traffic light or whatever) is just up ahead. And sometimes, particularly when starting up a climb fom a dead stop, I'd like to get a little extra out of 1st because the delay of shifting into 2nd is so long. I mean, by the time I'm in 2nd I've slowed to the point I should be back in 1st. And - like when I nursed her to the shop the other day - I used only 1st and 2nd, and (by necessity) never excceeded 1500 -1600 RPM. So my question: Is it permissible to rev (very briefly) beyond 2100 to make the 1st to 2nd transition a little easier (as opposed to lugging when she's finally in 2nd)? And is it okay (under limited circumstances) to keep the revs in the 1400- 1600 range? Any advice, tricks or secrets would fall upon thankfiul ears (eyes). Nellie Wilson | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 253 Registered: 10-2003 Posted From: 66.165.176.62  Rating: N/A |
Detroits like to be reved. Mine is a 6-71 but I don't shift until I get to 2000-2100. If you govenor is set correctly it won't let you go higher than it should unless you downshift to too low a gear. Coming home from my last trip I ran it at 2250 in 5 gear for 500 miles. Drive it like you are mad at it. I typically downshift around 1500 so as not to lug it | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1286 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
1500 might be a little low to downshift at depending on injectors and timing AND whether you are on level or climbing a grade. | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 254 Registered: 10-2003 Posted From: 74.244.14.221 Rating: N/A |
Thanks for the advice john. I'm new to this to so have been trying to figure it out as I go | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 923 Registered: 12-2000 Posted From: 71.54.29.215 Rating: N/A |
When we bought our first bus, a friend told me to slam my hand in the door before climbing behind the wheel to put my self in the right frame of mind to drive a DD ("drive it like you're mad at it"). Lugging a DD is the worst thing to do to them. I try to keep our RPM at 1650 or higher, we shift at about 2100. Jack | ||
| marvin pack (Gomer)
Registered Member Username: Gomer Post Number: 386 Registered: 3-2007 Posted From: 71.55.230.210  Rating: N/A |
the only way to drive a DD is comfortable!! Both feet FLAT on the floor and they love it man!! gomer | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1487 Registered: 12-2000 Posted From: 67.181.166.160  Rating: N/A |
Nellie (and others!) - Do you have both a working tach and speedometer? If so: Wind it to the governor in 1st, 2nd & 3rd, and make note of what the corresponding road speed is while the Detroit's screaming along behind you. It will NOT hurt the engine to run it at the governor for a little while - some bus drivers used to run down the highway in 4th gear sitting on the governor for hours on end. . . Once you've got this info, then take some white model paint, or white nail polish, and put a little dab on the speedo at the speeds for each gear you determined from your governor test. Or use a different color for each gear, whatever floats your boat. Once you've got your speedo marked, you'll always know what gear to be in at what road speed - simple, eh? No lugging, no over-revving - KISS!! Oh, one other note - when climbing hills, start your downshift 5 mph above then top of the next gear. Floor the throttle, kick in the clutch (keeping the throttle floored), slide the gearshift lever to the next lower gear, and, if you get the timing right, it will literally fall in and away you go. For more info, read the shifting commentary in "Articles of Interest" on this bbs. Now, I definitely have to go pack so I can head out to Quartzsite tomorrow AM. . . FWIW & HTH. . .  | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 132 Registered: 11-2008 Posted From: 70.49.113.66 Rating: N/A |
So, RJ. that old bus is just like us? It can always deliver a little more than the original design contemplated... at least for a short burst? | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 640 Registered: 10-2006 Posted From: 66.82.162.21 Rating: N/A |
DD rated the 8V at 2100 and it will run there all day. They went to 2300 for fire trucks , but lives were more important than a mere engine change. Hound set the coaches up for 1650 , about 62mph in a sportscar . So on every hound up shift the engine would drop to about 1000rpm as run thru the gears. No problems with "lugging" for those few seconds as rge rpm builds. This DOES NOT mean you can climb hills at 1200rpm floored , but screaming the DD is of no special use. The best fuel efficiency was done to be at 1800 rpm for gen sets and bif water pumps or boats. 10% over rom , or 1950rpm ia about the END of efficient operation . FF | ||
| Grant Thiessen (Busshawg)
Registered Member Username: Busshawg Post Number: 84 Registered: 10-2007 Posted From: 206.45.93.160  Rating: N/A |
Looking for yoru guys opinion, I always believed that as long as my 8v71 was increasing in RPM , speed I was not lugging it. Am I out to lunch on this? I always believed that lugging was when the unit was in a gear where it just kind of hung there, peddle to the floor and no increase in RPM. | ||
| Len Silva (Lsilva)
Registered Member Username: Lsilva Post Number: 193 Registered: 12-2000 Posted From: 24.164.20.23  Rating: N/A |
Grant, I think you are correct, Lugging occurs when there is no longer any throttle response at all. Nellie, If the governor is properly set up you could drive in first gear on the floor all day and not hurt the engine. You will hurt the mileage and the tranny would not be happy, but the engine won't care. I once worked at a facility that had a 6-71 powered standby generator. They would exercise it about 6 hours every week but didn't know that they were supposed to transfer the load to it. It ran at 1800 RPM with no load, six hours each week for years, never hurt it a bit. | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 135 Registered: 11-2008 Posted From: 74.13.196.64 Rating: N/A |
Len - and all you guys - thanks for the info. Very reassuring I must say (and right now I need some of that). Speaking of revs and lugging and such, would there be any reason I couldn't remove the transverse straps (belts) that turn (what I THINK is) the air cindtioning compressor? I mean, I'm sure not using it now. And I won't be until I get it refreshed and re-filled. It LOOKS like those belts run nothing else? So right now I'm just wearing them out for nothing and probably expending horsepower on a non-functioning system. Has anyone just taken them off... even if only for the winter? Thanks, Nellie Wilson | ||
| Glenn Williams (Glenn)
Registered Member Username: Glenn Post Number: 182 Registered: 6-2006 Posted From: 216.163.56.194 Rating: N/A |
Sure Nellie. Take the belts off and it won't hurt a thing. No problem putting them back on after servicing the system. Glenn | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 138 Registered: 11-2008 Posted From: 74.13.196.64 Rating: N/A |
Thank you, Mr. Glenn - That's a question I've been meaning to ask for the longest time but always forget. I've been tempted to take them off but, knowing my luck, would have soon discovered they're all that keeps the whole powerplant from flying apart. Nellie Wilson | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1289 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Bottom line is to find out the injector size and whether standard or advanced timing. Larger injectors and advanced timing like 1700 to about 2250 rpm range and will risk damage AND worse fuel consumption at full load at 1500 or below. The smaller injectors and standard timing like Fred is talking about run nice from about 1400 to about 1850. They will also tolerate being pulled down to 1100, since the small injectors don't create as much combustion heat. Also two valve heads on the older 71's liked the lower rpm range better. Funny thing is, sometimes going to advanced timing and or larger injectors improves the fuel mileage along with the power. You might gain a gear on some hills or it is more efficient at the rpms you are cruising and or running at. Since the timing of the instant of fuel injection into the cylinder is fixed on these engines, the best power and efficiency is going to be in a narrow band. Running higher rpm than the injection timing is set for is going to lag the proper time for that power production. Like retarded timing in automobile engines. Want to run in the higher rpm band because you have no overdrive or stuck with a numerically high axle ratio, then the advanced timing will be a benefit. Otherwise run at the slower speed and proper cruising rpm. The one nice thing about the DDEC engines is that the computer can change the timing to meet the rpm and load needs of the engine through the whole rpm range. Some dislike the computer versions because of reliability concerns, but that is the way to go. BTW, sometimes you need to go clear to 2100, 2200, 2250, 2300 against the governor because of climbing a grade and want to make up for that speed loss while you are waiting for the gears to synchronize or there is a wide spread between two particular gears. That won't hurt a healthy Detroit. The worse things to do to these engines is constant lugging, over speed down grades, and overheat. Running out of oil usually seizes the pistons in the liners before crank damage. Ok I'm done blathering now. | ||
| Arnie Smith (Arniemc5a)
Registered Member Username: Arniemc5a Post Number: 11 Registered: 11-2008 Posted From: 205.206.124.124  Rating: N/A |
I owned a Feightliner hwy tractor and put 350,000 miles on the engine before the top of a piston separated from the rest of the assembly. I ran that engine at 2000-2100 RPM as a normal operating range, and shifted at 2300 RPM. The oil was changed at 12-15000 miles, using 40 weight oil. By the same token I would run it at 1800 rpm without any problem or extra oil consumption... When we took the engine down to rebuild it the bearings on the crank, and main bearings had very little wear, and the only reason they were changed was because we had to change the piston, and it was purely a preventive move THe trick to driving any engine at any RPM is to let the motor breathe. That is, feather the accelerator with your foot so that ou can hear a difference in the sound of the engine with the slightest movement of your foot. Anything more than that and you are over fueling the engine, and it just returns to the tank. Lugging an engine can occur at any rpm if you don't "listen" to engine. A usual indication of lugging is a rise in the water and oil temperatures. Think of it this way... a smart runner paces himself and goes the distance. A person who doesn't, won't go the distance. | ||
| Arnie Smith (Arniemc5a)
Registered Member Username: Arniemc5a Post Number: 12 Registered: 11-2008 Posted From: 205.206.124.124 Rating: N/A |
An addendum to my previous post: I was going to add the there was an transportation company in Winnipeg with a fleet of trucks (10-15 at that time), that were powered by 318 DD - 8-71series and his motor life rarely surpassed 200,000 miles. The trucks ran from Winnipeg to Vancouver, Oregon, Washington states loaded heavy both ways. His philosophy was that the driver was to drive them as hard as they could. | ||
| Tony LEE (T_lee)
Registered Member Username: T_lee Post Number: 43 Registered: 11-2007 Posted From: 41.214.137.132 Rating: N/A |
The DD driver's manual specifies that on buses with 4 speed manual boxes, you should take it up to governed speed in each gear before changing up to the next gear. Because of the wide gear spacings, there is often a problem changing up when accelerating up a hill. It is obvious that the engine will be comfortable in the next gear up, but when you go to change up, by the time you complete the change the bus is slowing faster than the engine speed is reducing so you can't complete the change. In this situation there is no real alternative to going all the way up the hill in the lower gear at near governed revs. Noisy, but no harm done (except to pride as all those with 10-speeds race past) | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 641 Registered: 10-2006 Posted From: 66.82.162.16 Rating: N/A |
"Because of the wide gear spacings, there is often a problem changing up when accelerating up a hill" Some later coaches had clutch breaks to solve the problem , but the driver re training was too difficult (to NOT use it on EVERY upshift) , so service life was short. FF | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 142 Registered: 11-2008 Posted From: 74.13.197.138 Rating: N/A |
So, Tony, you hit it right on the head. I feel like a dolt, winding her tight in 1st when I'd prefer 2nd... but knowing I can't upshift without crawling to a near stop. Especially when cars are stacked up behind and no place to let them get around. But I'm getting that this is more a 'nature of the beast' problem - too much space between gears and no synchro - than just my own lack of experience problem? Nellie Wilson | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1291 Registered: 10-2003 Posted From: 71.58.110.9  Rating: N/A |
Welcome to driving these old coaches with standard transmissions. Whats really nice when you're tired after a long day and mistime a shift or two it sounds like grinding hamburger. How about going from neutral to first gear with engine idling while stopped when the tranny is nice and warm in an 04. | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 144 Registered: 11-2008 Posted From: 74.13.196.179 Rating: N/A |
Yes, indeedy, John. It sure is nice when you have to shut it down at a stoplight - especially on a hill - just to shift it into first. I try to slip it in (no Freudian implication) just before stopping but that clutch can get awfully heavy. Also a worry because I have a caution on my dash saying not to depress clutch when starting. I don't know what that could possibly hurt, but I try to avoid doing it. Trying to decipher your picture... is that a huge windhield I'm looking at? What kind of vehicle? BTW, what's an 04? Nellie | ||
| Ian Giffin (Admin)
Board Administrator Username: Admin Post Number: 1169 Registered: 7-1997 Posted From: 24.239.12.139  Rating: N/A |
Hi Nellie, Print out RJL's "Article of Interest". It is spot on and is the best resource for both the novice and for the veteran trying to break an old habit because they now have a cranky old shifter in their hand. Then, try this in your own driveway at a standstill: From neutral, pull back, yes, back toward 2nd, gently past the detent of the neutral position, but not so far as to grind the gears. Simultaneously (also not Freudian) depress the clutch and gently pull backwards on the gear shift lever placing it in second - if your timing is correct, the tranny rewards you by bumping the gear shift knob forward into your hand as you are pulling backwards. When you hear/feel the transmission accept second, push forward into 1st and let the clutch out slowly while accelerating. Then, as everything, practice, practice, practice. Ian www.busnut.com PS. The '04 you ask about is a GMC 4104 and you can find a picture of it in "The Bus Stops Here" picture book of buses on this site. | ||
| Patrick levenson (Zubzub)
Registered Member Username: Zubzub Post Number: 41 Registered: 5-2007 Posted From: 76.66.199.28  Rating: N/A |
An '04 is the best and the first of the modern highway coaches. All aluminum monocoque chassis, the shape of things to come in 1953. (Message edited by zubzub on January 17, 2009) | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 255 Registered: 10-2003 Posted From: 74.244.14.221 Rating: N/A |
Nellie. I think that photo in J Roan's avaitar is from a 70's B movie called "the big bus" about a nuclear powered bus | ||
| Jack Conrad (Jackconrad)
Registered Member Username: Jackconrad Post Number: 925 Registered: 12-2000 Posted From: 71.54.29.215 Rating: N/A |
"BTW, what's an 04?" Nellie, An '04 is a GM 4104. It is considered by most to be the first "modern era intercity coach". There were more of them made than any other model until the MC-9. Jack | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 427 Registered: 7-2006 Posted From: 70.210.250.246 Rating: N/A |
Geee Whizzz, bossnut...youse know your stuff! Is that peculiar to a certain category of coaches, or in general? I might want to try that with my Fuller Roadranger 10 speed, Cummins turbo, Crown Supercoach. Dare(should)I? RCB | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1294 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Tim, OF COURSE it's a B movie....it's about a BUS!! | ||
| Ian Giffin (Admin)
Board Administrator Username: Admin Post Number: 1170 Registered: 7-1997 Posted From: 24.239.13.27 Rating: N/A |
RCB, It took me about an hour to write that! Remember, I am a 6-speed Prevost flunkie. I'll probably end up buying one just to punish myself for ever having figured out how to get one to move in the first place. Translating Prevost 6-speed to MCI 4-speed (or are they 5-speed?) is like converting Fahrenheit to Celsius. Is that 5/9ths + 1/2 of 32 x2... er... uh... Ian www.busnut.com | ||
| R.C.Bishop (Chuckllb)
Registered Member Username: Chuckllb Post Number: 428 Registered: 7-2006 Posted From: 70.210.250.246 Rating: N/A |
....I thought as much...be careful U R using THAT word again!! KTF, and thanx....anyway.  RCB | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1465 Registered: 12-2000 Posted From: 76.68.133.189  Rating: N/A |
double and add 30.... so, 24 plus 24 plus 30 equals quite a party? happy coaching! buswarrior | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 149 Registered: 11-2008 Posted From: 70.49.113.186 Rating: N/A |
Hi Ian - Cool little trick. Haven't tried it yet (obviously) but will definitely give it a go. Read RJL's 'shifting' article and it made a lot of sense; sort of demystifies the fine art of not crashing crash boxes. Which reminds me... what's a 'drop box?' (From the context of recent posts, I've already eliminated the one under the toilet). Nellie | ||
| Paul Lawry (Dreamscape)
Registered Member Username: Dreamscape Post Number: 417 Registered: 5-2007 Posted From: 209.218.200.174  Rating: N/A |
One thing I will say Nellie, you sure do bring a new life to our fun hobby. Your comments brought a smile! Thanks! | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 151 Registered: 11-2008 Posted From: 70.49.113.186 Rating: N/A |
Well, Thanks, Paul. Warm words to my cold ears and much appreciated. I see you're from Abilene? That was one of the first Country songs I learned and still one of my favorites. I'll be cruising out your way soon (I hope)... maybe we'll run into each other? Coincidentally, just posted a note to Willie about that wild horse situation in Wyoming. How far are you from Austin? Nellie Wilson | ||
| Paul Lawry (Dreamscape)
Registered Member Username: Dreamscape Post Number: 418 Registered: 5-2007 Posted From: 75.145.74.185 Rating: N/A |
Hey Nellie, We are 221 miles from Austin, located west of the Big D on I-20 about 185 miles. Give us a shout when you are near. Home of the B-1 Bomber! Paul | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 642 Registered: 10-2006 Posted From: 64.241.37.140 Rating: N/A |
We have been fighting a shift hassle for a while. The engine RPM decay was just too long for "rapid" shifting . It would take 5 to 8 seconds for the rpm to drag the tranny down to the shift range. First "cure " was to grease the throttle cable , and repair the damage from "mechanics" at Carry Coach , the last engine change. When that didnt do it a bigger spring on the return , again no luck. The Bellows between the air cleaner chamber and blower inlet always was oily , and the old oil bath sparrow strainers are long gone for K&N's. So I decided to swop the air compressor for the on board spare. A pain to do as all the hoses had to be replaced , but better a hose replacement in my yard than alongside the slab. DONE, shifts better than any time in the past decade !!! Measure the time it tales for the engine RPM to decay , should be the same when cold as warm, mine was not , but now is. Good luck, FF | ||
| Jim Wilke (Jim Bob) (Pd41044039)
Registered Member Username: Pd41044039 Post Number: 354 Registered: 2-2001 Posted From: 69.77.144.28 Rating: N/A |
Gee Fred, I would have thought you would be changing out that nasty throttle cable with an air throttle..... (LOL!) | ||
| Don Evans (Doninwa)
Registered Member Username: Doninwa Post Number: 178 Registered: 1-2007 Posted From: 208.81.157.90  Rating: N/A |
OK FF, you lost me. How does changing the compressor affect shifting or the rate that the engine slows down? Don 4107 | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 693 Registered: 8-2006 Posted From: 64.55.111.6 Rating: N/A |
Don, I need that one explained too! G | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 694 Registered: 8-2006 Posted From: 64.55.111.6 Rating: N/A |
Nellie, I'm surprised you haven't gotten an answer to your 'drop box' question from an 05 or later Eagle owner, or the MC5 owners who have them. Anyhoo, a drop box is half of an 'over the shoulder drive,' where in Eagles the engine is set to the left, and in MC5s, the engine is on an angle, with the transmission pointing to the left of the differential gears. The driveshaft actually goes over the left axle, and the drop box gears take the motion and put it into the differential pinion shaft, which faces forward! Trust me, I don't have one, but thats how it is! Eagle did this when they moved the drive axle to the rear, and MCI did this on some of the 5s to make room. (Maybe on the V8s with autos?) If your engine is on an angle, you have one, if it is straight, you don't... HTH, buy the 6, George | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 167 Registered: 11-2008 Posted From: 70.49.114.182 Rating: N/A |
Dear George - I thank you for your explanaton. In my case, the engine seems (looking from the rear) dead on straight. But when the bus was on the lift - first time I had that perspective - I saw the differential (and associated stuff) was canted to curbside. I could easily grease the cans. etc. on the drivers's side but there was no clearance to curbside. (I got her greased, but required a 'nozzle fitter' while I pumped the gun). Nellie | ||
| ED Hackenbruch (Shadowman)
Registered Member Username: Shadowman Post Number: 95 Registered: 11-2003 Posted From: 72.62.250.195 Rating: N/A |
Nellie, easy way to tell if it is straight or not is to open your engine doors, stick your head in a little ways and look straight down at your bottom pulley and see if it is parallel with your bumper or if one side of the pulley is closer to the bumper than the other. If the latter is the case then you have a drop box in your bus. | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1494 Registered: 12-2000 Posted From: 67.181.166.160 Rating: N/A |
Nellie - All of the MC-5 series (A, B & C) had drop boxes. It was MCI's way of getting the longest wheelbase possible in a 35-foot coach using a T-drive powertrain. George (& Nellie, too!) - MCI offered the following powertrains in the MC-5s: All MC-5As & Bs: Your choice of an 8V71/4-spd manual or an 8V71/4-spd manual. All MC-5Cs: Either an 8V71/4-spd manual or a 6V71/HT-740 automatic. There is insufficient room back there for an 8V71/HT-740. Those were the available powertrains OEM from the factory. Now, folk have stuffed an 8V71 bolted to an MT-644 Allison in the 5s, and that works. But the real "hot rod" is to stuff a 350 hp 6V92TA/HT-740 combination back there - lots of go, with decent (for a bus) fuel mileage. Drop box can handle it fine, Eagle offered the same powertrain OEM. Turbo has to be off-set to one side, as the blower compartment sits too low, but that's the only major change - other than bigger radiators to keep the beast cool. Clear as mud? FWIW & HTH. . . | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 169 Registered: 11-2008 Posted From: 70.52.100.254 Rating: N/A |
Dog-GONE it you guys! Every time you tell me something, I gotta go out in the cold, drive umpteen miles, grab my flashlight, pull off my blanket (the one covering the engine) and compare what I see with what you wrote. But this one is pretty weird. Truly. The bottom pulley (and the entire 'back' of the motor) is dead square to the rear bumper (for a visual, check the pic on my 'A/C Pulley' post. BUT the diff and drive train are definitely off-set (towards curbside.) If I didn't fear a reincarnation of Norman Bates I'd just stay in motels. Nellie | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 695 Registered: 8-2006 Posted From: 12.69.89.106 Rating: N/A |
Nellie, RJ has done his usual good work! But the heck with the blanket on the engine, look at the driveshaft! You will find that it goes over the left axle, and the 'front' universal joint is actually in front of the left axle by a couple of inches. I've never looked at the engine in a 5C, all my limited experience is with what I think was a 5, and its engine was angled. Somebody explained the differences between 5s, 5As, and 5Bs once, but I don't remember what it is. The differences in a 5C are obvious, then you have the Saudi roofs and extra A/C model. I should have just said a drop box wasn't a black water tank, and left well enough alone! Told ya to buy the 6, (just kidding, kinda) George | ||
| Nellie Wilson (Vivianellie)
Registered Member Username: Vivianellie Post Number: 172 Registered: 11-2008 Posted From: 70.52.103.80 Rating: N/A |
Well, darn it, George... if I don't strike better luck with this '5' pretty soon, I may trade it for John's '6'... I'll be looking at it on Friday (God willing and the creek don't rise). My bus doesn't seem to fit anybody's description of anything. My engine and air appliances don't look like BW's photos (great pics anyway). My drive train is on the right (curbside) but my engine is bang-on straight. I can't wait to meet some of you guys and get a better handle on this stainless steel crate. And my drop box IS a black water tank . Nellie | ||
| joe padberg (Joemc7ab)
Registered Member Username: Joemc7ab Post Number: 327 Registered: 6-2004 Posted From: 66.38.159.33 Rating: N/A |
Nellie Could it be that you have a "Four" or perhaps earlier? 6V71? and the driveshaft going straight into differential? RJ There is a '77 5B sitting a few miles from me, equipped with 6V71 and 644 auto equipped that way from new. Weren't the Saudi busses equipped with the 644? Nellie, Get us some pictures!!! Joe. | ||
| Tim Brandt (Timb)
Registered Member Username: Timb Post Number: 258 Registered: 10-2003 Posted From: 66.165.176.62 Rating: N/A |
Nellie, You have something that looks alittle more like this? I still need to drive over to the bus and get those photos of the 6-71 mousetrap and stop soloniod http://members.tccoa.com/timb/Flx/100_5831.jpg | ||
| ED Hackenbruch (Shadowman)
Registered Member Username: Shadowman Post Number: 96 Registered: 11-2003 Posted From: 173.117.73.87 Rating: N/A |
Joe, what kind of shape is that 5B in? Running?, or a parts bus? | ||
| joe padberg (Joemc7ab)
Registered Member Username: Joemc7ab Post Number: 328 Registered: 6-2004 Posted From: 66.38.159.33 Rating: N/A |
Ed That bus is complete, and bodywise in good shape. Mechanical unknown. It is owned by an indian band that used it once upon a time to make trips to Vegas with it. It has been sitting for about 6 years since they now have their own casino built with vegas money as I understand it. I sent a nice letter to the chief and council a while back expressing my interest, but never received a reply. Even after contacting his personal secretary numerous times. I was interested in the 644 for my MC1, but that is now evolving to the 6spd manual since I now have all the pieces. You might recall my post on the shifter saga where I bought the shifter along with the bus attached to it and another bus for good measure. Joe | ||
| ED Hackenbruch (Shadowman)
Registered Member Username: Shadowman Post Number: 97 Registered: 11-2003 Posted From: 72.62.161.165 Rating: N/A |
Ok, thanks Joe, i was kind of hoping it was a parts bus. | ||
| RJ Long (Rjlong)
Registered Member Username: Rjlong Post Number: 1495 Registered: 12-2000 Posted From: 67.181.166.160 Rating: N/A |
Joe - Since '77 is the last year for the 5Bs and the first year for the 5Cs, I'm not surprised that a B came out of the factory w/ the automatic. But notice that it's bolted to the six, rather than the eight - factory being conservative? Probably not - it was most likely ordered originally for airport shuttle service or similar, where HP isn't an issue, but working traffic is. Nellie - Since you've learned to post photos, how about posting a few of your 5C, in order to thoroughly corn-fuzzle the troops! A 3/4 front right, 3/4 front left, 3/4 rear left or right, couple of the interior, etc. FWIW & HTH. . . | ||
| joe padberg (Joemc7ab)
Registered Member Username: Joemc7ab Post Number: 330 Registered: 6-2004 Posted From: 66.38.159.33 Rating: N/A |
Ed What might you be looking for? Parts that is. | ||
| Buswarrior (Buswarrior)
Registered Member Username: Buswarrior Post Number: 1478 Registered: 12-2000 Posted From: 76.69.142.53 Rating: N/A |
Geez, am I going to have to drive down there? happy coaching! buswarrior | ||
| ED Hackenbruch (Shadowman)
Registered Member Username: Shadowman Post Number: 98 Registered: 11-2003 Posted From: 68.27.121.26 Rating: N/A |
I am looking for the spring loaded bay door struts that as far as i can tell, they only used on the 5B. I have one on my 5A and would like to find 3 more. | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 666 Registered: 10-2006 Posted From: 69.19.14.28 Rating: |
How does changing the compressor affect shifting or the rate that the engine slows down? Don 4107 Every diesel is an oil burning engine , any oil , not just diesel. When the air compressor gets really old the engine oil in the compressor can be sucked past its rings and into the engine. On Sportscars the compressor is hooked to the engine filtered air supply , so the path exists. AS the engine is run to full throttle before each shift , there is enough suction to pull the air from the compressor into the engine. Only a few drops of oil will be enough to cause the rpm decay to be slower , and 6 seconds to return to idle is FOREVER !! on a hill. FF | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1314 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
If oil get past the rings, it will go out the exhaust valve to the air tank. The only way that I can see it getting up the air intake port is if the air filters are so clogged as to try to pull air along with oil sucked past compressor compression rings from the compressor air inlet tube. Since it is 2 or more feet of hose uphill to air cleaner and there is going to be suction on this hose from air going to the compressor any time it is running and especially at high engine rpms , it doesn't look feasible to me. One thing that I think would help would be to reshim the endlay in those transmission shafts, maybe replace mainshaft bearings, possibly might create more drag like when new and help. Most of those old trannies are well worn and gears coast nicely when oil is hot. Or maybe a manual tranny oil cooler would do the trick. Speculation only; I'm not going to spend the time finding out. BTW, the coach shifts very fast when cold. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1315 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
One thing that definately aggravates this situation is if the clutch drags, even a little. When trannie is hot and you push in the clutch, the gears should STOP turning after some to several seconds. If they never stop and you have to shut the engine off to get it into gear without grinding, you have a problem with the clutch or pressure plate dragging, keeping the trans shafts turning and causing that grinding. Could be as simple as adjustment, but usually is worn clutch linkage parts causing lost motion, a warped clutch disc, out of adjustment pressure plate fingers, or wear or warpage. | ||
| George M. Todd (George_mc6)
Registered Member Username: George_mc6 Post Number: 705 Registered: 8-2006 Posted From: 64.55.111.6 Rating: N/A |
"The oil in the compressor can be sucked past its rings and into the engine" ? Don, I don't think we got the correct answer. The compressor is indeed lubricated by engine oil, so below the piston (the compressor crankcase) has engine oil in it. Above the piston, any oil passing the rings will be pumped into the air system. When the compressor is unloaded, I guess some oil could get into the intake air line. BUT, the oil would be taken right back into the compressor the next time it was loaded. Not to mention the big knock from "fuel" being in the cylinders before top center, and enough oil getting into the engine to keep the revs up would cause huge oil consumption. G | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 669 Registered: 10-2006 Posted From: 69.19.14.40 Rating: N/A |
My theory is speculation based on the FACT that the rpm decay got far better after changing out the air pump. Since shifts are started at top rpm the suction in the air box would be highest then . There is no other explanation I can think of why the unit got better , after the change.. FF | ||
| Don Evans (Doninwa)
Registered Member Username: Doninwa Post Number: 181 Registered: 1-2007 Posted From: 208.81.157.90 Rating: N/A |
Interesting. I suppose that when the compressor is unloaded and pumping air back and forth between cylinders, if oil is getting past the rings that charge of air could become saturated with oil mist. Since the intake valves are held open by the unloader there is a path into the intake. Did you notice any change in oil consumption after replacing the air pump? Were you getting oil from the air tanks or dryer? I plan to change my compressor because there appears to be quite a bit of oil coming from the air dryer. I will have to check to see what the intake looks like to see if it has been finding it's way into the engine too. Don 4107 | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1317 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
Fred, I would think that a new or rebuilt compressor would have a great deal of drag from the new rings and bearings and create more drag while working. When one is shot, it doesn't put much load on the engine or create as much air volume. Sort of like a worn out car engine not having much compression anymore to hold back on a downgrade. After changing to a new or rebuilt compressor It is going to take several purge cycles to completely eliminate the remaining oil from the system. I would do a compressor first and after a few miles and compressor cycles miles, do the air dryer. I wouldn't want to get any remaining oil in system in the new cartridge, even though it has a built in purge system. Leave your air tanks open all night to get the clinging residue on inside tank walls to drain completely. Just like leaving an oil container drain a while to get those last drips of oil.If you never have done this, the next time you change your oil, drain those containers into something for a couple of hours and see how much you get. | ||
| FAST FRED (Fast_fred)
Registered Member Username: Fast_fred Post Number: 672 Registered: 10-2006 Posted From: 66.82.162.18 Rating: N/A |
Almost all the time the air compressor is doing no work , it comes on very little on a bus that stands for weeks. I would have a hard time thinking the rings on the compressor are slowing the DD from top rpm to idle very fast, it should be minor HP , no load.. The air dryer is the old style , muffler , and does not purge much oil when I chose to do it. The first air tank does have less oil , but it never blew much on purging. I use a weight on the pull chains , about 1-ce a year to get the last drop, but its so EZ to do , normally the tank is purged 2-4 times a day , on a pit stop and walkaround . Why it shifts so much better may remain a mystery , but I am delighted that it DOES! FF | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1325 Registered: 10-2003 Posted From: 71.58.110.9 Rating: N/A |
How about also the generator charging, creating more drag. Maybe some other things were done at the same time as changing over the compressor. | ||
| Gus Causbie (Gusc)
Registered Member Username: Gusc Post Number: 821 Registered: 11-2005 Posted From: 208.54.200.42 Rating: N/A |
Nellie, To answer your question directly; leave it in first until you can maintain enough speed to comfortably shift to 2nd. Take it all the way up a hill at gov rpm in first if necessary, this won't hurt a thing. This is common practice on heavy trucks. First gear in them is so low that you can't get up enough speed uphill in first to shift to 2nd without stopping. Diesels don't mind running a long time in first gear. They will even run cooler this way than if lugged in a higher gear. Bus manual trans gears are too far apart so there is a great difference between 1st and 2nd. This is the pits when starting uphill! |
