Powerplant change?

[Paladin]

I know I'm getting wayyy ahead of myself but I was wondering. If someday in the future I wanted to put  a 6v92T in place of my 8v71, what exactly is involved? I know you need the larger radiators but is it pretty much an easy swap or is there a bit of fab work that must be done?

-Dave

[H3Jim]

If its not too late, buy the bus with the powerplant you want, or perhaps trade your bus for one that has the powerplant you want.  You'll problaby never get your money's worth out of the change, and ti fraught with lots of problems and issues.  It can be done, and lots of folks have done it, but its best to avoid if you can.

[uncle ned]

jack and jerry campbell are putting series 50's in a eagle and a mci

the eagle was down at jack's rally last year  It looked like a factory job

ned

[tekebird]

Although th 50 series is a modern motor it is not that good in a coach application

[Brian Diehl]

I put a Cummins ISM and Eaton Autoshift in my MCI 96A3.  It was certainly a lot of work, but has turned out great.  I'd do a few things different if I were to do it over, but nothing major that can't be corrected over time as I'm inclined. 

[jjrbus]

 I purchased my bus in 99, it has a 6V71 auto. I spent many hours reading about, talking about and researching a 6v92 swap. After a couple of years I decided no way, no how. It can be done I just do not want the headaches and expense involved. If you are a diesel mechanic with a big shop and an unlimited checking account, well you would not be on here asking about it!
With the price of bus's today it makes far more sense to buy the injun and tranny combo you want. However if you have that bus nut mentality, that I can do it even though it makes absolutely no sense financialy or mechanicly, time wise or any other way.That spending my money and time changeing an injun, tranny, sounds like more fun than traveling and enjoying the bus. Then go for it. It's your bus do it your way.

[chris4905]

Dave,

An engine and/or transmission change/upgrade is so involved, I'm not sure where to start.  I know first hand, I just finished replacing/upgrading both.

Took out the 8v71 and put in a 6V92.  Took out the Spicer 4 speed, but in a V730.

What type of bus do you have?  I have instructions for the transmission upgrade to a GMC bus, in digital, and can email it to you.  The engine is another issue.  So much involved, I'd have to have a more specific question to answer.

I know this doesn't help a lot, but can't do better without knowing what type of bus you have.

[TomC]

Tekebird- I beg to differ in your opinion of the Series 50.  Except for the fact that it is a tall engine like the Series 60, and gives off some vibration at idle (not too much if you have the right engine mounts), I think the Series 50 is the perfect bus conversion engine.  You can get 350hp and 1150lb/ft torque from it, it weighs about as much as the 6V-92, will get close to 10 mpg, is a proven 1 million mile engine, has a good Jake brake, and is quieter than the 6V-92.

As to changing out the 8V-71-at this point, turboing the 8V-71 to get more power, that is a good choice-I did it and am extremely pleased with the results.  I went from 300hp and 800lb/ft torque to 375hp and 1125lb/ft torque with 9G75 injectors.  You can go with 90 injectors for 450hp and 1350lb/ft torque-that takes you into the 8V-92 realm of horsepower. It is MUCH easier to use the 8V-71 again, rebuilt up into a turbo and air to air intercooled engine rather than replacing with a 6V-92.

If you still want to replace the 8V-71, I would NOT use another 2 stroke in its place.  Rather a Detroit Series 50 or 60, Cummins M11/ISM, Caterpillar C12, C13 of the 4 stroke variety will be more prudent since the 2 stroke mechanics are getting fewer and fewer in between and the straight 40 weight Delo 100 type oil is getting harder to find.  Using a 4 stroke engine, especially one that is electronically controlled will get you an engine that will get 8-10 mpg, compared to the 5-7mpg that most of us are getting with the 2 strokers.  Good Luck, TomC

[tekebird]

to each thier own. I don't disagree with you points

I didn't like the performance of the 50 series I drove..and the two outfits that I know that had them in 35 foot coaches didn't care for them either.

the 40 wt is not getting hard to find...it is just not on the shelf anymore unfortuantely.

I myself prefer the simple 2 strokes ( non electronic)  never had had any issues with finding someone to work on one....in fact have never "needed" to find someone.  I am lucky enough to have a DD 2 stroke specialist just up the road a bit.....thats all he works on.......and when he dies......hios son also only works on two strokes.  and they are real mechanics.....not technicians that you find at the DD dealer.

ouside of that the ht of both the 50 and 60 make it a difficult install as a powerplant swap.

[msheldon]

The question is, what are you trying to achieve by swapping the 8v71 for a 6v92T?

Swapping different blocks involves a lot of work. I was all set to swap a 8v92 for my 8v71, ended up putting in a freshly rebuilt 8v71TA. Still had a bit of work re-routing exhaust and intake, but it was a *LOT* less work than building new motor mounts, new bell housing and clutch, modifications to the engine cradle, etc...

[blue_goose]

Just some info from one of the people that did put a Detroit 50 in a 05 Eagle.  This is the third engine to be in my bus.  8-71 first that was rebuilt, then a change to 8-92 at 475 hp.  The 8-92 always wanted to run hot and the best fuel milage I could get was about 4.5 per mile.  The 50 has been in the bus 10 months and about 8000 miles.  My average milage has been 7.8 and no heating problem.  I have lost a little power from the 8-92 but very little. 
The 50 is the same length as a 8-71 or 8-92 only taller.  On the Eagle or MCI you don't have enough room for the longer series 60 without a lot more work. 
We are going to start the change in Jerry's MCI just after Jacks rally in FL.  Don't think it will be as hard as the Eagle.  There is lots more room with the MCI.
With all these changes I should tell you that I have had my bus for 21 years and put over 170,000 miles on it.  We lived full time for 5 years and loved every day of it.
Jack

[prevost82]

You must of had a worn-out 8V92 and live where there is no real grades. I have a 475 hp 8V92ta in my bus and a friend has a S50 in a 102A charter bus ... I took the S50 out for a ride (empty bus) and on a 6% grade 3 miles long it was down to around 30 MPH up the last part of the hill... my bus will go up the same grade loaded towing a Jeep GC at 55 MPH.
Ron

[johnjem]

i just completed a 8v71 swap with a fresher 8v71 did it all by my self with a pallet jack had to even swap out cradels boy it took a beating out of me! oh yes i used a back hoe to move the motors <

[blue_goose]

When you compair two different buses that doesn't mean anything.  My 8-92 was a reman by Detroit and when I took it out only had 68,000 miles on it.  Did you compair the rearend and trans with the two buses.  What was the HP set at on the 50 series?   Was the 50 wore out?  Did the air to air (intercooler)have any leaks? What was the turbo boost at full RPM?
This could keep on, but sometimes we just do things because we want to.  I get to drive more motorhomes and buses than most.  Some of the 300 HP units that I drive seam to have more power than other 450 HP units.