L head or F head

I am very sorry to be such a noob and ask so many questions. I will say that this forum has been a wonderful resource and that I really do appreciate your help.

Not knowing much about this Jeep I thought that I could just pull the head off and get the valves worked on and the springs replaced. I called a machine shop in town that has a good reputation and they gave me a ball park of $2,000 to rebuild the motor. They said that the exhaust valves were in the block, etc, etc.

The motor really ran fine when I took it out. All I want to do is give it a once over and make sure that it will run for another 56 years or so.

I tried to figure this out with the aid of Google, but sometimes a picture is worth a 1,000 words. What motor is this? How do I know what motor this is? Being that it ran well when I took it out, can I replace things like springs without needing a complete rebuild? I have the Jeep Bible and I can turn a wrench, but I do not want to foul this up.

 

F-head. If it has a valve cover then it is an F-head. Yes the exhaust valve is in the block, but the intake valve is in the head.

 

Hey and welcome!

You may have to register on that site to see this, but here is a pdf that will help you a lot ... in general. It's the manual for the military version of your engine. Ignore any electrical, as it's 24V, and the carb and some external plumbing will be different, but the internals should be pretty much the same.

http://willysmjeeps.com/downloads/M38A1-Engin.Clutch.pdf

 

I don't understand why you would take apart a good running engine ?
they are tough old birds
the springs shouldn't need replacing; is one broken ?
a compression and leakage check would have been nice before teardown.

regardless, as mentiond above, you have an F-Head.

 

F-head as stated.
I agree with jpflat2a ,

Exhaust valves are behind the plate, behind the exhaust manifold.
(Though mine are out at the time of the pic.)


Ahh here is one

 

Like others have said....test compression and leakdown...if everything checks out good...clean her up and fire her up after tune up parts. If you want to make her pretty...and at least have the piece of mind...pull the head and check everything out, mill the head (get a little more compression) and put fresh gaskets in it.

Also, looks like someone has already pulled the generator in lieu of a 10si delco alternator....but holy crap is the belt not lined up......

Maybe someone else can chime in on this...my F head (1955) does not have the breather hose coming out of the valve cover...was this an addition later on?

 

Take a look here:http://www.film.queensu.ca/cj3b/Tech.html Scroll down to get to the f-head section, lots of answers there. If you have it out and the head off, here's what I would do. Pop the rocker assy off the head, and do a quick lap on the valves. Degrease and reassemble. Degrease motor, check cylinder walls for scoring or damage and ridge at the top. If no obvious defects, flip it over, pull the pan. Clean out the sludge from the pan, and also oil pump pickup. If you're worried about clearances, pull a bearing cap and plastigauge the bearings. Get a gasket set, reassemble and adjust the valves. I would not recommend taking the exhaust manifold off as you'll probably break half of the studs off in the block. (it always happens, it's not your ability). Throw tune up parts in the dist, check clutch assy for wear, replace as needed. Plop that ole girl back in and run it for another 50 years! Barring any major defects you can do all this for cheap.

 

Dad always said "don't fix it if it ain't broke"

 

Thank you all very much.

That sounds like what I will do. I did pull the transfer case and transmission because they had water in them. The motor itself ran very well when it came out. I think that I will follow your advise and clean it up and shoot some paint at it.

Thanks again!

 

Also, looks like someone has already pulled the generator in lieu of a 10si delco alternator....but holy crap is the belt not lined up......

Yeah, there is no telling how long that has been that way. I have already found a number of "fixes" that I am having to go back and correct.

 

Maybe someone else can chime in on this...my F head (1955) does not have the breather hose coming out of the valve cover...was this an addition later on?

The hose coming out the top of the valve cover is for positive crankcase ventilation. Clean air is drawn through the crankcase and valve chamber. Engine vapors are prevented from entering the atmosphere this way. Early emissions control.