MC5 71 to 92 swap

[artvonne]

  Curious how much is involved swapping a 8V92 in place of an 8V71. 92 is out of a truck. Will everything swap over, housings, flywheel, accessories, or do you need a whole bunch of 92 specific parts?

[bevans6]

The 92 will fit, Steve5B has an 8V92N in his MC5B.   To do it "right", ie, the way I would do it   read my project page on installing the 8V71T in my MC-5C.  Your project will be similar.  First thing to check is the accessories on the back of the engine, does it have a power steering pump drive in the left-most position.  Where is the compressor drive.  What is in the right hand cam drive position where you need to put the belt drive for your alternator  What other drives are there - anything on the blower drive position that you will need to remove?  Is the bell housing the right one?  Is it the right size, are there mounts for the pickup points for the cradle mount?  Is the flywheel set up for a two disc 15" clutch like the MC-5 engine has?  I don't know if the flywheel will swap from the 8V71, but memory suggests it will not.

At the front of the engine, you will have to either change the front cover for the MCI one with the round boss for the engine mount, or be real lucky and it will already be there (not likely, but you never know.  Changing the front cover isn't hard, just time consuming.  You may have to change the crank pulley to one with the correct grooves for the blower belt, I don't think the 8V71 will swap on, but what you have on the 92 may well be fine.  You probably will need to change the thermostat housings for the ones that work with the cooling system plumbing on the MCI - changing the left hand thermostat housing means the front engine plate has to come off, which makes the problem of changing the front cover kind of moot, since it comes off before the engine plate does.

I suggest that you read my article, then take a close look at both engines.  You'll see the differences.  I think the 92 is about 3/4" longer than the 71.  If your new engine is a turbo, then you have the problem of mounting it, again my article discusses what I did.  There are other solutions - I know that Ken McKarl installed hydraulic motors to run his blowers so that he could put the turbo on his 8V71T on top of the engine, and there is that MC-5C that has the whole engine compartment remodeled to put the blower shelf up as high as a mc8/9, so that the turbo fit on top of the engine.

Edit:  forgot that you would have to install some cooling upgrades, new radiators or similar.

Brian

[Lin]

What transmission are you attaching it to?  Make sure it is rated high enough.

[artvonne]

What transmission are you attaching it to?  Make sure it is rated high enough.

  Standard spicer 4 speed transmission.

  Brian, currently all three rear accessories are correct, PS pump far left, then compressor, belt pulley on right. Belt pulley only has two sheaves.

  I want to say up front its a real stretch I will ever attempt it, but its interesting to contemplate it. A lot would depend on how much stuff would interchange.

  The radiators look to be pretty fresh and clean. If I did this I would take a wait and see approach. I could also detune the motor down with smaller injectors.

  Or just boost the 71 a bit and forget the whole engine swap BS, lol

 

[lostagain]

Paul,

just run what you got. It will get you down the road just fine. That is what the bus was designed and built with. You'll be busy enough maintaining it, tuning it, tweaking it, etc.

Yes a swap is a nice dream. But the time and money involved in doing it would be huge.

Yes it would be fun to do, if, like me, you like fixing and building as much as driving it and camping in it.

I would not consider it unless your current engine was dead. Even then, overhauling it would be the easiest, most practical.

4 or 5 years ago, I pulled the 4-71 out of my Courier 96 to fix a few leaks. And got carried away and overhauled it to turbo specs, installed a turbo, etc, etc. Took me all winter, or about 4, 500 hrs. Was it worth it? Yea. In all respects.


One side of the brain says go for it, the other side says no way. That's why we are bus nuts, LOL.

JC