Replacing an L4-134 in an M38

I am restoring my granddad's '48 M38. I took the engine out in plans to take it apart, have a machine shop go over it, and hopefully rebuild it. As it turns out one of the pistons exploded and tor up the cylinder. So unfortunately I think the block is toasted.

I think my only real option is to replace the engine. Does anyone have any suggestions of an easy replacement. As far as I know it has the original Transmission (T-90). If at all possible it would be great to keep the existing transmission and bell housing. If any one has good suggestion on where to look for this too that is also help. I don't have a 'network' of sources so any thoughts are appreciated.

thanks again.

 

V6 are common and easy to work in , you have the buick v6 which came in front of a T90 for the most part . A 4.3 chevy motor is a good swap also , just need to get the correct bell housing and input shaft . Or if you look around you might can find a decent 134 . Ill ask my friend nick , he might know where something is south of richmond.

 

F4 or L4 would be the easiest/simplest
F4 requires an opening be cut into the hood for carb clearance though.

 

Just get another flathead. It fits right in, you will have spare parts, it keeps it more original. They are more nostalgic, and run great as well.

 

OMG!!! Don't cut the hood!! INstall Ford Falcon carb on the F head and keep the hood intact. Check out the CJ3A page for more info.

You'd be suprised what can be done for an L head to restore the block to running status. I'd keep it and tear into it to actually confirm what is damaged first.

 

I would do anther L head you can pick them up fairly cheap. You can get rebuilt ones for just over $2000, you would have close to that rebuilding and buying the adaptors to fit a different engine in. Go to midwestmil.com

Also double check the date on the jeep, the m38 was not made in 1948 it was produced from 1950-1952

 

Thanks for all the comments, you guys are awesome. I have attached a picture of the hole for those who are interested.

 

Might be able to sleeve it. Check with a goood machine shop in your area. Ask around for references locally. Won't be cheap, IIRC sleeving is about $100/hole.

A replacement L134 would be the easiest route. I don't think there's anything special about the M38 engine compared to the civilian engines. Post up at Willystech http://www.willystech.com/parts/board.shtml or the G http://www.g503.com/forums/ to see if you can easily find a block in your area.

A different type of engine is quite do-able, but any swap other than a F134 is a whole different universe in terms of amount of work and difficulty. Lots of people with average skills do it though ... depends on what you want to have when you are done.

 

The m38 and cj3a engine a basically the same. The casting numbers will be the same as well. Just the M38 engine above the water pump will have MC ######## or RMC########

 

Figure out if your engine is the original engine or not. If it is the original, do whatever you can to keep it. If it is not original, then try to find a flathead as close to original as you can.

 

The thing with post WW2 jeeps the engine serial number does not match the Vin so changing it out wont effect orginality at all. If it is an m38 finding another MC or RMC engine would be best.

 

Unless I am missing something, It looks to me like as if this engine has a hole in a piston but no other obvious damage. Even with my magnafying glass I see no rerason that you can not rebuild this engine with a new set of pistons. Does anyone see something else?
It looks like some thing went through the engine, a nut down the carb perhaps.
Take this block to the machine shop and let them give you their professional advice. This should only cost you the time to tear down the engine, as you have to remove it for any engine swap anyway. While I am older and my eyes are not what they once were and the picture is very small, I really think that this engine can be saved at minimal cost. I have saved some that looked worse then this one does.
Pull it out and tear it down. What can you hurt? You may find that it is easily repairable.
IF you choose to replace it I vote for another L-134. My next choice would be a F-134 with a 1962 Ford Falcon Holly carb (no hood cutting) It is almost a bolt in swap. Last but not least The Buick V-6 actually was installed in the CJ-5 in the 60s &70s. You can get the bell housing ETC.
Good luck, Matt W.

 

Oh I see it now, Thanx.
Well, it can be sleeved. If your machine shop can sleeve it for about $100 you are at about the cost of a good core. I think that unless you really want this perticular engine, you might be money ahead to find a good running engine to replace this one with. Some folks like to replace running L-134s with a bigger engine like a SBC. You need to find one of them and buy his old running L-134. Post an add here in the CJ-5 parts wanted section. Good luck, Matt W.

 

Thanks again for all your help.

The number off the top of the engine by the water pump is (as best i can figure it) 840161.

There is another number along the lower left side that i need to clean more to read.

The ID plate is in pretty bad shape.

It says :

ORD STOCK NO. 6795532
ORD SER NO. - no longer readable -
MFR SER NO. MC- 12000
YR MFD - 1951 (sorry i was wrong, it is not a '48 )
MFR PART NO 657116
CONTRACT NO. W 20 089
ORD 4758

Is there a good place to find out what these numbers mean.

I am guessing now that the engine is not original. Nonetheless, i have a trusted machine shop that said they could do a complete machining, sleeve, clean, valve job etc. for 500-600. So i am may go ahead and continue down that road.

 

What you have is a very early m38. Can you post some pics? If you post over on www.willysmjeeps.com Wes will be able to help you, he knows m38's very well.

 

I work at a machine shop in Leesburg, VA. I'd be able to sleeve it for you and since you're a fellow jeeper who's had a bit of bad luck I should be able to cut you a deal and rebuild the whole motor for under $2000.