MCI-5B transmission options

coachconverter · July 02, 2019, 05:19:00 PM

Dredging up a really old topic...

Has anyone put a more modern drivetrain in MC5A? Like a Series engine and B transmission, or ISC, etc...

luvrbus · July 02, 2019, 06:23:05 PM

They have enough room for 50 series with a B400 with a Cummins it get a little tight because of the drop box

coachconverter · July 03, 2019, 12:23:13 AM

Thanks for the reply, that's what I was thinking too, Series50/B400. Guess I'll just need to figure out the mounts and a few dozen other things...

buswarrior · July 03, 2019, 05:52:14 AM

Vertical clearance for a S50?

Neat job, take lots of pictures for us!

Happy coaching!
Buswarrior

bevans6 · July 03, 2019, 07:06:58 AM

I measured once, when I was at the non-rally in South Carolina and several guys had S50's in their MCI 8's and 9's. There is about a half inch clearance vertically to the roof of the engine bay if the crankshaft is at the same height. But - the S50 needs about half the radiator capacity, so a big opportunity to remove the roof, redo the whole fan situation, and reconfigure for a single radiator. The guys with the S50's loved them, but they had sufficient room for transmissions that could live with the 3.73 drive ratio.

buswarrior · July 03, 2019, 10:49:17 AM

Lots and lots of transit buses ran their whole lives with the 6th gear locked out on the B400. 5th and 3.73 would be a charm.

If it will fit... that would be a fun ride!

Happy coaching!
Buswarrior

Oonrahnjay · July 22, 2019, 07:57:35 AM

Quote from: buswarrior on July 03, 2019, 10:49:17 AM
Lots and lots of transit buses ran their whole lives with the 6th gear locked out on the B400. 5th and 3.73 would be a charm.

If it will fit... that would be a fun ride!

Happy coaching! Buswarrior

BW, *is* there a 6th gear in a B400? A B400 has gone into my bus and I've looked at specs. All I've ever seen is a listing for ratios for 5 gears forward and reverse. I hope I've missed something and I'll have more gears than I thought I did.

bevans6 · July 22, 2019, 08:12:18 AM

The Allison bus transmission brochure says it's a six speed - says ALL of the B series are six speeds. The B400 has .75 and .65 overdrive ratios, fifth and sixth. Says it's 28.3" long. Doesn't say if that includes a yoke or drive plate. spec length on the MT 640 series is 30.4", or so says the interweb.

chessie4905 · July 22, 2019, 08:27:05 AM

https://www.allisontransmission.com/docs/default-source/marketing-materials/sa7760en-bus-series-brochure-lr8fed7259281567eeb272ff0000a566aa.pdf?sfvrsn=aff13d1d_8