CJ F134 in a M38A1

[SFCKUNERT]

Does anybody know if it is possible to drop a F134 engine that came factory in a CJ, into an M38A1 and still maintain the originality of the M38. The donor engine appears to be about the same year as the M38a1. Any help would be greatly appreciated.

[Ben Dover]

The front engine plate is unique to the M-38/M-38A1 because of the configuration of the 24 Volt generator bushings, it should be changed and is no simple task. The tubing installed in the plate is longer. The fuel, vacuum and oil lines are an easy change over.

[USMC M38A1]

the side cover will have to have the pcv valve added instead of the blowdown tube also prety simple change over,along with valve cover my block was a civilian block out of a cj5 but I had a donor f134 military for all my plates and suchyou will have to put the plate on it behind the flywheel also common to military only and flywheel is smaller was on my civilian motor as well as belhousing but be assured it can be done you will need a gasket kit because you will have to pull the front cover to remove the plate fo the engine mounts.

[Cuz]

If the CJ5 engine came in a CJ5 then it alreay has the PVC valve in the side cover and not a road draft (blowdown) tube. It should also already have the correct rear plate, flywheel and etc. Some older F134's made circa 1950 had the small bell housing for the small frame starter and 124 tooth flywheel.

As Joel mentioned it's a straight forward swap and if you have an original M38A1 engine in there then you have all parts that need to be swapped to the civvy engine.

[SFCKUNERT]

USMC and Cuz,
Thanks for the great words of wisdom. It looks like I will be removing the original engine from the A1 for a complet rebuild and replacing it with the donor that I purchased recently. This engine was actually removed from the previous owners M38A1. Can you tell from the block numbers if the case in in fact an original M38A1 engine. I am going to get it power washed tomorrow and get some pics taken which I will attempt to post on here for you to check out, but that always seems to be quite the task for me.

Does anybody have the link handy with the instructions for posting pics within a message?

My great buddy and friend Leonard Nettles will be coming all the way to Ohio to assist me with the engine swap in 2 weeks, so I have alot of work to do. Do you have any suggestions as far as parts I need to purchase to attempt to start the new engine once we have it in? I know for sure I will need a new set of plug wires (the old ones were dry rotted and trashed), and radiator hoses.
Should I have the radiator and gas tank already sent to the shop and back? What are they going to do to them, as far as restoration goes, just power wash and ensure they seal correctly? If so this is something I could do myself and save a few bucks!!! Neither of these are rusted out. It appears to have all the fluids drained before sitting!


Thanks again fellas for your help, and I'll let you all know how it turns out. Once I figure it out, I'll also post pictures for your viewing pleasure!

[Cuz]

There were several block castings (number is on the lower right side of the blocks) for the F134 starting in 1950 and running through 1971. The number that tells you what model chassis the engine was originally built for and installed in is the serial number on the small flat above the water pump. The prefix ID's the chassis IE "T" = truck, "U" = Utility/wagon, "J" = Cj, MD = M38A1. 4L was a very common prefix from the late 50's on and didn't help ID the original chassis anymore. An extra "R" in the prefix meant the engine was a brand new replacement engine from the factory.

You said the CJ5 engine came out of your friends M38A1. You should compare the welded steel bushing length on the front engine mount plate for the generator mounting to determine if the plate is CJ5 or M38A1.

Generator ears

Gen Mt Ears.JPG (29.79 KiB) Viewed 1427 times

Mount bracket

Gen Mt Brkt.JPG (35.74 KiB) Viewed 1424 times

You should sort out the front engine plate issue right away. If you do need to switch the plates it requires pulling the timing cover and the timing gears. Make sure you use the correct puller on the fiber cam timing gear or be prepared to buy a new gear. You will need several gaskets up front and you should have the book on the bench when you start.

The radiator and tank shops will go as far as you tell them too. If you are confident they are both corrosion free and only need a cleaning then of course go for it yourself. It won't hurt to take the radiator to a shop and have them test it under pressure and flow check it.

[Ben Dover]

And do not drive on the fibre timing gear with a block of wood with the camshaft installed in the block, get a 1/2" longer bolt to draw it on, otherwise you just may loosen the expansion plug at the rear which will allow oil to leak and oil pressure to be lost.