Repower expertise

[Sean]

OK, folks, here is a question for all the powertrain experts:

What 400+ HP engine/tranny combination is neither longer nor taller than an 8V92/HTB748 but is also narrower?

Here's my issue:  we are pulling the above-mentioned power train out of the bus even as I type.  The fit is so tight that three of us have spent two days trying to squeeze it out.  That doesn't count the day and a half to first disconnect everything, and then remove the generator (really) to get at the last three cradle bolts.

Getting it back in is going to be just as hard if not harder.  And I have always regretted not re-powering the very first time we had the engine rebuilt.

I have the sense that one of the Cummins powerplants coupled to a B500 might work, but this is definitely not my area of expertise.

The current power train is all electronic, and the replacement will have to be likewise.  We have 475 HP right now, but I am willing to give up a few ponies for an easier fit, better mileage, and less overheating.  At 48,000 pounds, I don't think I can afford to go below 400 though.  The replacement would also need either a retarder (preferred) or jakes.

Ideally, we'd find someone who will take our current powertrain in trade, but I definitely want to start with a fresh rebuild and not simply a used motor.

Any suggestions?

-Sean
http://OurOdyssey.BlogSpot.com

[lostagain]

Why are you pulling the 8V92?

JC

[Busted Knuckle]

Why are you pulling the 8V92?

JC

He has a end plate or accessory drive housing gasket leaking and the only way to fix it is to pull it, separate the engine/trans, and remove the housing from the engine, fix the gasket and put back together!
  BK 

PS Joel did the exact same job for me on the same exact engine trans combo, but it was on a different German bus! (mine was a Setra while Sean's is a Neoplan!)

[HighTechRedneck]

These photos will better illustrate the close fit Sean is referencing.

[eddiepotts]

Just to bring it up it is wise to use new fasteners on a rebuild. I know Sean's engine is not as old as most but think of the thermal cycle they go through while stretched everyday. 1980 was 31 years ago.  They loose their tinsel  strength and you can not torque them. They will tighten to whatever foot pounds but they will not stretch and wont stay tight. The results are leaking gaskets. If you EVER find a leak and for some reason the bolts seem loose don't waste your time just spend a few bucks and buy new bolts. they will pay for them selves in loss of oil or pulling an engine to change a gasket. FWIW

[Ace]

Sean a couple things come to mind. One your buddy Steve had a real fresh 8v92 and teams that came out of his bus. Still fits waiting for a new owner. Its at Johns! Then two are living it up in the Bahamas right now but from the stories I heard, its a good motor and would be a direct replacement. On the other hand there have been a lot of guys repowering the 8v's with a 50 series. Dint know if that motor is bug enough for your bus or not but it is a 4 stroke and can put out the same hp as the 8v's.
Just thought if refresh your mind!

[TomC]

Sean- I know when my Caterpillar 3406B gets to the point that I have to either rebuild it or have to replace it if smog laws ever go into effect in California for RV's (my truck is now registered as a motorhome) I will repower with a Cummins ISL 8.9 liter 450 @ 1250lb/ft torque.  This is an RV rating and quite frankly so close to the 8V-92TA's rating, I don't know if you'd feel the difference.  If you did, it might be 3-5mph on the hills.  BUT-the fuel mileage gain is going to be impressive.  And with being able to use the smaller B400 (which is essentially the 3200TRV), you'll also have two overdrives to slow down the engine.  Also, the engine will be about 700lbs lighter, and the transmission 250lbs lighter.  You'll probably be able to reduce the size of your radiator, but you'll have to add an air to air intercooler.  In my optinion the Cummins ISL is the best engine for any bus conversion.  You can or not get a hydraulic retarder on the Allison, or you can get a Jake brake on the Cummins.  I'd just get the Jake brake.  It's about time you get that dinosaur out of there!!
Right now I'm working with Cummins to approve the ISC 8.3 liter at 350hp and 1000lb/ft torque (like a 6V-92TA) for 80,000lb service in city pickup for mainly port service-gives you an idea what Cummins thinks of that engine. Good Luck, TomC

[TedsBUSted]

These photos will better illustrate the close fit Sean is referencing.

Wow!

[Brian Diehl]

Sean,

In looking at your pictures I think you might be able to fit a Cummins ISM in there.  Couple this with a B500 and you might be okay length wise.  The ISM will give you more torque and allow for lower RPMs.  With the weight you are pushing the increased displacement would be good.

Brian

[Tom Y]

Sean, I have the L10 with a 3200sp Allison. The M11 is the same length, not sure of the other Cummins ,ISM,ISL. But I will get an overall length if it will help? I could look and tell you how much longer the B500 is also? I would think the later M11s are in the power range you want.

Brian, Is the ISM the same length as the M11?    Tom Y

[luvrbus]

A 60 series is only 1 inch longer than a ISM the height is the killer on a 60 series 51 inches tall, the ISM has been replaced by the ISX 11.9 if you are going to swap just raise the deck or lower the engine mounts and go with a 60 series and a B500 (34 inches L) I think the 60 series would serve you better than a ISM in 50,000 # bus and don't leave out the Cat engine a 3406 E will move that Neo lol .
Call me if you go with a ISM I have friend that has a new 500 hp he decided not to use in his Prevost he went with a 60 series for fuel reasons when Bill at Cummins told him to expect 5 MPG

good luck

[rv_safetyman]

Tom C has a ton of "inside information" because of his work in the trucking industry.  He recommends the ISL as a candidate.  To me that is a bit small for a 50K vehicle, but if Freightliner is thinking about using them (albeit city service) they must be pretty robust.

If they would work, you can find them in a bunch of motorhomes with the Allison attached.

There are lots of buses that folks have installed the L10/M11/ISM in.  Have not really heard anything bad about them in terms of power.  Some folks say they are a 500K engine.

As Clifford said, the Series 60 and the big CAT and Cummins are pretty tall and probably not an acceptable choice.

Adding the Charge Air Cooler is not trivial in most buses.

When you consider that Sean does not tow a vehicle, the 50K is not all that much different from than many of us that tow big vehicles.

Random thoughts.

Jim

[Hard Headed Ken]

What I have discovered during my engine swap is that there is not much flexibility in engine location when you are working with short drive shafts (around 12" to 14"). If you want be sure you have no drive line vibration issues you can only get away with about 6 degrees of misalignment between the diff and trans plus the transmission shaft and pinion shaft must be parallel to one another. So you can't cheat on alignment by tilting the transmission up or down to get the alignment within range. The complete engine / trams has to raised or lowered to keep the components parallel. That could make the engine height a determining factor for your coach.

Ken

[HighTechRedneck]

A couple things about Sean's bus that open up some flexibility in length are:

• It hasn't been measured yet, but at a glance the drive shaft is 30"-36" in length.
• It currently has a large retarder unit that adds about a foot between the output of the 748 transmission and the driveshaft.

So there is some room for negotiating there.  If the new engine was equipped with Jakes, then no retarder is needed.  And there would seem to be some margin for shortening the drive shaft a little.

Height, now that is quite a different matter.  As you can see in the photos, there is nothing to spare on the top without an interior remodel of the bedroom.  The bus has a relatively low ride height and the skid plate has taken a fair amount of action getting through driveways and such.  So not much room to extend down.

[TomC]

I still stay with the Cummins ISL theory.  But-and it sounds like you do-with the extra length, you might be happier with a Cummins ISM that can be turned up to 500hp and 1550lb/ft torque.  The big difference is you have to use the bigger B500 transmission.  With the ISL, the B400 is used which is based on the 3000HS series.  In trucks, the 3000HS is rated up to 370hp and 1250lb/ft torque at 80,000lbs.  It would be a cheaper and easier conversion then the Cummins ISM.  The Cummins ISM will be longer then the 8V-92TA.  The Cummins ISL is about the same length as the 8V-92TA.  I wouldn't use the Detroit Series 60, no matter how excellent (and I love that engine too) it is-it is just plainly to big and weighs more then the 8V-92TA by about 250lbs.  Good Luck, TomC