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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: bevans6 on October 02, 2010, 04:46:19 AM

Title: 6V92 and 740 install in MC-5C
Post by: bevans6 on October 02, 2010, 04:46:19 AM
I'm going to get serious about searching for a good setup to swap into my MC-5C.  The initial questions that I have are, presuming the right engine and transmission, what changes do you have to make to engine mounts and the drive shaft?  Can I swap over the belt drive alternator pulley from the 8V-71? 

Next is, how do I find the right engine and transmission?  Buy separate and mate them together, or buy a pair?  do they have to be from a bus or can they be from anything?  I would probably want to stay mechanical so I don't have to learn the DDEC conversion.  If you are buying a used engine, can you trust the seller on the condition if you are buying from a bigger name distributor?

Finally, anyone have one for sale? 

Thanks, Brian
Title: Re: 6V92 and 740 install in MC-5C
Post by: luvrbus on October 02, 2010, 05:07:04 AM
Buy from a MCI 9 with the transmission you don't even want to go there trying to make a truck engine or any other model 6v92 other than from a MCI work buy it with the cradle and you don't even need a different drive shaft the alternator drive is not a problem if the engine comes with the gear driven alternator use it if you need a accessory drive and want to keep the belt driven I have one I'll give you.
MCI did some crazy stuff on the back of the engines
.
good luck
Title: Re: 6V92 and 740 install in MC-5C
Post by: TomC on October 02, 2010, 08:46:08 AM
The nice thing about 2 stroke Detroits, are their similarity between engines.  The 8V-71 and the 6V-92 should be almost identical on the front pulley.  You simply line up the 6V-92 in the same place as the 8V-71 using the same engine mounts, then the radiator blower V belt should line up.  You'll have to modify the rear transmission mount and get a new drive shaft made.  The coolant lines should be the same, just have to figure where you want to mount the turbocharger.  Turbos can be mounted on top, to the side, in back of the engine-so long as the turbo is still higher then the oil pan for gravity draining back to the pan. Personally-would do the swap in a second if I had a 5.  Will make a real sports car out of it.  Good Luck, TomC
Title: Re: 6V92 and 740 install in MC-5C
Post by: lostagain on October 03, 2010, 06:04:24 PM
My 5C (new to me), has the 6V92/740. Nice combination. The turbo is on the driver's side. No room for it under the bedroom floor. The alternator is belt driven at the back, and is awkward to get at. So is the gear driven air compressor, at the back too. The mileage is reasonable, I don't know the figure, I just fill up when it gets to near empty.

JC
Title: Re: 6V92 and 740 install in MC-5C
Post by: christopher on October 03, 2010, 06:24:06 PM
my 5c has the 6v92 with the 644t trans.
theblower deck was rasied up and the engine will fit
let me know if you need a few pics
chris mci 5c
gets about 6.5-7 mpg
Title: Re: 6V92 and 740 install in MC-5C
Post by: Fredward on October 05, 2010, 07:53:33 PM
Having removed the 8V71 from my MC-5 to replace the clutch, I researched briefly the automatic options. Staying with the 8V71 I discovered that only a 640 series Allison will fit in the short space. I'm interested to hear that a 6V92 which is a very common engine mated to a 740 would also fit in that tight space. Is this really the truth? If so, that combination would make the bus really move and there should be lots of them already sitting on an MCI cradel for you. A fair amount of re-plumbing is required to re-locate the turbo, but thats not the end of the world.

But the experts are saying that engine/transmission combination will fit in an MC-5?

Fred
Title: Re: 6V92 and 740 install in MC-5C
Post by: RJ on October 05, 2010, 10:19:09 PM
Fred -

Quote from: Fredward on October 05, 2010, 07:53:33 PM
But the experts are saying that engine/transmission combination will fit in an MC-5?

Beginning with the 5C model, MCI offered two different powertrains - either a manual 4-spd with the 8V71, or the automatic HT-740 bolted to a 6V71.

Since the 6V92 shares the same dimensions (h x w x l) as the 6V71, it's an easy fit, with the exception of the turbocharger & it's plumbing.  Like JC said, the ones I've seen have had the turbo mounted on the driver's side of the engine, low enough to clear the stock blower compartment floor.

It is my understanding that MCI made some structural changes with the 5C to allow the big 740 to fit.  Based on that, I'm not sure if this powertrain would be a "simple bolt-in" swap if you had a 5A or 5B series.  You might have to use an MT-644 in that case - but you could keep your 8V71.

FWIW & HTH. . .

;)