rebuilding the 871 or repower with cummings

[la chiva]

hey guys
i'm thinking to rebuild my 871 in my 4107but for the price i started to think maybe
to repower with a cumming 8.3 anyone as done this?? the work involved what would be
the perfect match engine tranny any suggestion??

[lostagain]

Are you rebuilding it yourself for the price of the parts?

Are you having it done at a diesel shop for 20 to $30,000?

The cheapest is doing the overhaul yourself, and slide it back in.

Swapping for something different will involve a lot of fabricating motor mounts, intake and exhaust plumbing, looking for a suitable transmission, bell housing, etc, etc.

The strickly logical answer is: overhaul what you have. Or look for a bus that has the drivetrain that you'd rather have.

Now if your heart really tells you to go for a different engine, tranny, for more power, better fuel mileage, bragging rights, etc, then go for it, but it will take a lot of time and money.

JC 

[la chiva]

actually i am having the engine rebuilt by detroit the cost about 15,000
i think i can do the repowered with a cummins for a few thousand more
my friend as a old flexliner that is repower with a cummins on the same trip cost him
alf the price in fuel  and it's getting harder to find 2 stroke mechanic on the road

[luvrbus]

Your friend has a bus that is easy to do a repower the engine turns in the right direction buy the time you buy a ZF or Allision V730R transmission with all the parts and do the fab work and spacers 20 grand is on the low side

[morefire]

Re-power with the Cummins

BTW,  $30 to rebuild a 8v71?!?!?!  Are you kidding me? 
For that kind of money you can install an ISX or C15 with 600+ horses, and even the wheelie bars that you would need.

[la chiva]

i already have a alisson 730 on the bus

[la chiva]

and probably can get my hands on a 8.3 cummins with allisson 6 speed serie 3000
for about 6,7000 with almost no milleage

[buswarrior]

I think we're confused?

A 4107 has a V drive.

The engine rotates in what is described as a left hand direction, or backwards, from everything else. You can't just source any old engine to swap in, or you will have to drive it forwards in reverse gear, and not very fast, however, it will be a blast in the other direction!

The busnuts who have actually taken a project to that point are hard to find, and they don't talk much about it...

There is a reverserer available for the V730/V731 transmission to "turn around" a right turning engine, but you have to find one that isn't worn out from its transit duty. The later models of the RTS were available with right turning 4 stroke engines using this reverser ahead of the Allison V drive often with a hydraulic retarder too. Designated VR731R.
I've seen L10 Cummins and S50 Detroits in the back of RTS hooked to VR731R transmissions.

You won't be able to use any other type of transmission in a GM coach except a V drive.

Unless, you want to take on a conversion to a T drive set up, like the MCI/Prevost/Eagle/Setra/Van Hool/etc/everything new.

And that's a big, big job, that takes deep pockets, and/or a lot of sweat.

happy coaching!
buswarrior

edit: I should mention that ZF had a 4 speed auto in V drive configuration that I have seen hooked up to an L10 Cummins.

[la chiva]

hey busswarior
this is exactly what i was thinking to convert to a t drive since the cost of rebuildind my 871
at detroit is about 15 000

[robertglines1]

15grand would total many buses of your vintage. Must be a lobor of love. Seams you could find a good runner with a 100,000 miles left in it for 3 grand. Just a thought. If you are in love with it and have deep pockets go for it. Just remember you will either have to make it longer or loose inside space and move drive train around to t-drive. Longer I would think by several feet and create a new frame system. I don't think the present engine mounting system will support the extra weight that far back of the axle. Just some observations. Need to talk to someone that has done it in your particular type of bus. Doesn't the roof structure actuall carry  most of the engine weight or do I have it confused with some other type of bus?  Bob

[la chiva]

also the reason i am here is to get as much intel as possible and the pros and cons
of a job like this. from all of you guys that been around these bus for years before i decide
what to do

[luvrbus]

That would be a job with nothing to weld into on 4107 the rivet,drill bit and bolt suppliers would love you lol buy another bus that one will wind up the scrap yard trying to do a T drive

[buswarrior]

I think the cost of paying someone to convert the coach to a T drive would fail the cost-benefit calculation by an exponential magnitude.

Best to figure that you'd neither get a penny of it back in re-sale, nor would you recoup much in operating efficiencies unless you drive it many thousands of miles a year, for many years.
In fact, I think it will make selling the coach harder, or impossible, as the "extreme modifications" will scare off the few potential purchasers of an old GM bus conversion.

That being said, if you have the money and want to spend it this way, there are folks on this and the other board who have lots of good advice as to how to go about designing the conversion to T drive.

Let the investigation continue!

happy coaching!
buswarrior

[oldmansax]

I think we're confused?

A 4107 has a V drive.

The engine rotates in what is described as a left hand direction, or backwards, from everything else. You can't just source any old engine to swap in, or you will have to drive it forwards in reverse gear, and not very fast, however, it will be a blast in the other direction!

The busnuts who have actually taken a project to that point are hard to find, and they don't talk much about it...

There is a reverserer available for the V730/V731 transmission to "turn around" a right turning engine, but you have to find one that isn't worn out from its transit duty. The later models of the RTS were available with right turning 4 stroke engines using this reverser ahead of the Allison V drive often with a hydraulic retarder too. Designated VR731R.
I've seen L10 Cummins and S50 Detroits in the back of RTS hooked to VR731R transmissions.

You won't be able to use any other type of transmission in a GM coach except a V drive.

Unless, you want to take on a conversion to a T drive set up, like the MCI/Prevost/Eagle/Setra/Van Hool/etc/everything new.

And that's a big, big job, that takes deep pockets, and/or a lot of sweat.

happy coaching!
buswarrior

edit: I should mention that ZF had a 4 speed auto in V drive configuration that I have seen hooked up to an L10 Cummins.

I used to have a full sized, fully equipped shop, and a friend who had a fully equipped machine shop. We overhauled an antique genset engine in a boat. Poured the babbit bearings & turned the rings, sent them out & had them chromed. Changed truck engines. Lengthened & shortened frames. Electrified a truck for theft deterrent one time. Twin-turboed an 8V-92. Put a 1693 Cat in a Marmon. Put an Allison Aircraft engine on his sawmill. Built a set of headers for a 549 International...... Now, that thing did sound good!   Lots of crazy stuff.

The only reason I can see for doing what you describe is the challenge of doing it & the bragging rights of having done it, as others have already said.

If you do this, figure it's gonna cost twice what you think, it will take at least twice as long, and, if you are particular like me, you'll have to do at least three of them before you're happy with the results.

TOM

[bevans6]

Those buses were specifically designed to replace the engine in a day.  I would find another known good drive train out of a similar, newer GM, and stick it in.  Others have done so on this board, with great success.

Brian