6V92/auto swap into Mike and Lori's old coach?

oldmansax · September 21, 2017, 04:54:46 PM

I'm sure a lot of you know Lori is going to sell the coach they bought from me ('72 MCI MC7) since Mike passed away. I know I should not even be thinking about this but how much trouble would it be to swap out the 8V71/manual with a 6V92/auto? The 8V runs and shifts fine but I can't deal with the manual anymore. I'm guessing the coach is only going to go for about $15K so would it be worth it? That was our first coach and you know how it is with your first love LOL! And, Mike did a boat load of work to it.

Don't tell me I'm crazy 'cause I already know that!

TOM

PS: Here are some pics when it was mine and some of the work Mike did:

https://photos.app.goo.gl/DY4ZCb9FCzq1qemC2

bevans6 · September 21, 2017, 05:31:30 PM

If the MC7 has the engine/tranny sitting on a slide in engine cradle, I would guess that if you can find a power package complete from a MC-9, it would be a very easy swap - as long as the cradles are compatible. That is the question to ask - what is the compatibility between the MC-7 and a drop-in package from a later bus?

Brian

luvrbus · September 21, 2017, 05:49:01 PM

The MCI 7 has so much room in the engine compartment you can install about anything in one with out much trouble even the 8v92's with top mounted turbos

TomC · September 21, 2017, 07:16:39 PM

If you have the length, just take out the 4spd manual and install an Allison HT740. Both have 4th as direct drive. All you'd have to add is a transmission cooler, shifter and throttle modulator. Good Luck, TomC

oldmansax · September 22, 2017, 06:03:53 AM

Clifford, I was thinking in terms of cooling as well as room.

TomC, I think Clifford actually has a 740 Mike was thinking about installing. Of course, I want the auto but I also want the turbo to improve performance at higher elevations........ and a Jake! I guess i could soup up the 8V like you did. LOL! You probably got $20K in that.

My wife says she doesn't care if I have fantasies, just don't indulge them!

TOM

luvrbus · September 22, 2017, 06:13:43 AM

Just de tune the 8v92TA to around 400 hp or less it will cool

eagle19952 · September 22, 2017, 06:49:58 AM

Quote from: luvrbus on September 22, 2017, 06:13:43 AM
Just de tune the 8v92TA to around 400 hp or less it will cool

and live a longer happy life

luvrbus · September 22, 2017, 07:02:01 AM

I do have the 740 but I don't know if Mike ever bought the shift tower he probably did since there are so many salvage yards around the Phoenix area

bevans6 · September 22, 2017, 07:39:42 AM

On my bus the shift tower, shifter, trans-end mechanism and the custom made cable got me no change from $1000, but all new. After my three day struggle to install a new throttle cable years ago, I was not looking forward to installing the shifter cable. It did take the better part of a week to get the old clutch linkages, shifter linkages and such out (old bolts well seized) but I pulled the clutch pull-rod out and pushed the new shifter cable inside the tube the clutch pull-rod had been in. So installing the new cable was literally done before I really got started, it took about a minute and a half...

Brian

TomC · September 22, 2017, 08:39:35 AM

If you can install an 8V-92TA with high turbo, an 80 injector will give you 400hp and 1200lb/ft torque-50% more than the 8V-71 is putting out. Course you can get the same power out of a 8V-71TA also with 80 injectors.
I can tell you I'm very pleased with my 8V-71 with 75 injectors putting out 375hp and 1125lb/ft torque. I cruise at 1850 which is 60mph. Coming down from the bay area on Wednesday, I got 7mpg. Good Luck, TomC

oldmansax · September 22, 2017, 07:32:53 PM

I don't really need the horse power. A 6V92 w/jake and an auto tranny would suit me just fine.

TOM

eagle19952 · September 22, 2017, 09:52:05 PM

you don't need 400hp to do 60mph.

i don't.

bigred · September 23, 2017, 06:51:05 AM

Quote from: oldmansax on September 21, 2017, 04:54:46 PM
I'm sure a lot of you know Lori is going to sell the coach they bought from me ('72 MCI MC7) since Mike passed away. I know I should not even be thinking about this but how much trouble would it be to swap out the 8V71/manual with a 6V92/auto? The 8V runs and shifts fine but I can't deal with the manual anymore. I'm guessing the coach is only going to go for about $15K so would it be worth it? That was our first coach and you know how it is with your first love LOL! And, Mike did a boat load of work to it. Tom,Where R U located I know a man in N C that I think could help you out .Let me know if you would like his number>

Don't tell me I'm crazy 'cause I already know that!

TOM

PS: Here are some pics when it was mine and some of the work Mike did:

https://photos.app.goo.gl/DY4ZCb9FCzq1qemC2

TomC · September 23, 2017, 07:27:42 AM

You're correct you don't need 400hp to go 60. But the extra torque sure irons out a lot of hills. When these buses were made, trucks crawled up 6% hills at 25mph. Now trucks do 45mph. I pull south bound I-5 Grapevine in second doing 45mph at a comfortable 1800rpm. Good Luck, TomC

bevans6 · September 23, 2017, 08:03:50 AM

The first time I drove from Ontario to Nova Scotia I had the old worn out 8V71N set up for 318HP (N65's and A timing). I was in third gear on most of the Ontario hills and in second gear on a lot of the Quebec and New Brunswick hills, and the road through NB is basically a hill, either up or down, there is nothing flat about it.. The second time I drove it from Ontario to Nova Scotia I had the new 8V-71T with N80 injectors and 405HP, and traffic aside I down-shifted from 4th to 3rd exactly once. Big difference, far bigger than I expected. I would leave the pedal where it was, and you could just hear the governor ask for more power as it dug into the hill. I rarely even went to full pedal.

Brian