cross mating M151Engine to T90 Civilian Tranny

Since I jumped in and posted yesterday, I might as well go with both feet.
I've asked this on 2 other jeep forums with no good answers yet. As I mentioned in my previous post, my 62 CJ5 has been cross bred with a M151 Mutt engine and transmission. I like the engine ok but am not thrilled with the transmission. It doesn't align to the right load front and rear differentials causing vibrations, the welded crossbred drive shafts make me very nervous and has other issues that annoy me.
Anyway, the question is has anyone tried to cross mate a M151 engine to the original 3 speed 3 stick transmission and transfer case? I might be getting a parts jeep with the parts to swap if I can make it work. My M151 engine runs like a sewing machine and I would really prefer to keep it if I can. If I get the parts jeep it will also have the F-head 134 but I don't know it's condition.

Scott

 

As long as the bell housing length allows the T90 to go behind the engine, You should be able to make an adapter plate along with a clutch plate and throwout to do the conversion. The M151 Engine is a very good engine, and you are correct, you will not like the transmission.

 

This may not be the answer you want to hear, but you'd probably be better off selling the engine & getting something that is easily adapted into the Jeep.

 

colojeepguy, My engine is already adapted so that is not an issue as much as the tranny. I'm starting to believe that I may be the first guy to come up with this idea. The M151 engine is not dramatically different from the f-head 134. They are both 134 CI 4 cylinder engines. The exhaust valves and manifold placement are the biggest visible differences. I'm hoping maybe that I'll be able to mount the t90 to the M151 bell housing and then only have to use the civilian clutch and pilot bearing/bushing. If it gets much more complicated than that I will probably go with the original 134 engine worry about other things my jeep still needs. Money is more an issue than time and mechanical ability. I just don't want to get too caught up in fabricating adapters and such.

Scott

 

I think this is on the mark. You keep focusing on the transmission, but which transfer case do you have? Don't you have the Mutt transfer case as well? If you are going to change back to the original drive train, then there's not much reason to put the Mutt engine back in. It won't be any cheaper to have a custom adapter machined for the Mutt engine than to buy an aftermarket adapter that fits 90% of all GM engines. These adapters can also be found used, if you look around.

I'd sell the Mutt parts to a M151 owner/collector and use the money to help pay for an engine donor.

 

Timgr, the M151 transmission has an integral transfer case, center drive front and rear. I'm hoping that an adapter won't be necessary to get the M151 engine to bolt up to the t-90 tranny. My original question was more of a "has anybody done it before type thing. When I get my parts jeep, I'll be able to start doing side by side comparisons and measuring. With hunting season over I can take my jeep back out of service and tinker pretty much until October. I'll post some updates on what I do.
I realize that my jeep is already an abomination to the purist types but it was bought already crossbred, making me feel less guilty about further mods. One day I hope to get my hands on a late 50's early 60's jeep wagon and then try to go the total restoration route. My grandfather used to take me hunting and fishing in such a rig.

Scott

 

Yes, I suspected that the Mutt has some kind of integral setup.

I think you may as well be hoping you can drop a Chevy engine into a Ford, and it will bolt up. The Mutt engine is completely different from the Kaiser F134. If you want an absolute yes or no, try posting your question on G503.com - the guys over there are more familiar with the Mutt than we are here. But I'm sure that they will tell you no, that they don't bolt up.

 

I am a member of G503. They do know there M151's there but are not terribly up on civilian CJs. I asked the question over there about a month back and never got a real answer. I fear my thoughts on it are that I'm the only one who considered cross mating the M151 to a civilian tranny. Oh well, time will tell if I can pull it off.

Scott

 

No harm in trying to mock it up. I would not buy any parts until I had the F134 and the Mutt engine side-by-side. The stickout of the F134's T-90 is pretty short - Novak has a new adapter that will work with the short shaft T-90s, but all the GM engines will then interfere with the firewall.

There are two ways this swap could work without a custom adapter. First, if the Mutt and Kaiser bell patterns are the same, you can bolt the Mutt engine to the F134 bell and run it. Second, if the transmission pattern is the same between the T-90 and the Mutt transmission, and the input shaft stickouts are the same, you could bolt the Mutt bellhousing and engine directly to the T-90, and work out the clutch bits. This too is highly unlikely.

If neither of those work, you'll need to make a plate adapter that goes between the Mutt bell and the T-90. If the Mutt bell is shallower than the F134 bell, there will be room for the plate without changing inputs. Otherwise, you'll need to use the longer Utility Wagon T-90 input shaft, which will make room for the plate (this is usually how GM engines are swapped to the T-90).

If you want to take your Mutt drivetrain apart, I expect members here can get you some pictures and measurements of the T-90, and the back of the F134. This will give you a better idea of whether your idea is practical.

 

Just kinda thinking out loud here-
You mentioned the centered output on the M151 tcase as being an issue. How about swapping to a centered rear diff and keeping the trans/tcase that you have?

 

For whatever it's worth, I looked up a few numbers on the M151 engine:

Displacement: 141 CI
71 HP @ 4,000 RPM
128 lb-ft. of torque @ 1,800 RPM
Compression ratio: 7.5:1

Whereas the Willys Hurricane (F-134) numbers are:
Displacement: 134 CI (obviously )
75 HP @ 4,000 RPM
114 lb-ft. of torque @ 2,000 RPM
Compression ratio: 7.4:1

All I know about the M151 engine is what I've copied here, but it seems possible that it's a bit more modern design than the Hurricane. That being said, its numbers don't appear to head-and-shoulders above the F-head, and while a MUTT engine in a basically stock CJ5 drivetrain would be very different and cool to see what it was like, it may not be the thing to do on a budget. Depending on your budget and what condition your parts Jeep is in, it might be too expensive just to put the F-134/T90/D18 back in your Jeep - things can start adding up, particularly if it's not a true drop-in swap where all the donor parts are already in good, ready-to-run condition.

Just my two cent's-worth. Good luck with your Jeep.

 

I thought about going to a center load rear end at least....don't use the 4 wheel drive much anyway. The problem there seems to be finding one in a price range I can live with. The parts jeep I've found is cheaper than a rear differential by itself. Problem there is it is also a right side load.....

Scott