willysmjeeps.com

I got my gasket set from Midwest Military with a composite gasket and I do not recall any instructions on sealant. If I recall correctly I asked the machine shop/engine builder what he would do. He even loaned me a spray can of the copper sealant but did advise that they can be put on with or without the sealant. He also said it would not hurt to put the sealant on and that it might be a good idea. And the guy does have some experience with these engines, but not as extensive as Wes has.

I am going to check with John at Midwest to ask if he has any input into this conversation and I am also going to check with a couple long time Willys guys in my club. The common thread may be what Wes just posted. If it does not say to add sealant, don't do it. I will post any additional information I get for the benefit of us novice "mechanics".

I still have not heard back on what sealant to use around the head bolts. I believe I used either No.2 non-hardening form a gasket or more likely the Aviation form a gasket liquid. Is there some specific thread sealant to use?

Also, is it a good idea to replace head bolts? Mine looked okay and did not appear stretched and worked for many years on the engine until I cracked it open. Thoughts and ideas appreciated. And thanks Richard. I am glad I am not alone in this club.

Mike

On my M38 I used a metal/fiber gasket with the metal side towards the engine block as per directions. I treated the metal side with a copper spray sealant. Important fact I discovered is that the copper sealant will not seal perfectly until the engine has been run up to normal operating temperature. Clean the block carefully to remove any traces of oil or previous sealant. Install head, torque bolts carefully and use sealer on the threads. Fill radiator with coolant and quickly start the engine and bring it to normal operating temp. Rechecked torque after shutdown. Haven't had any problems with leakage.

Everything mentioned in this thread has been addressed completely in the links I posted for your reading pleasure.

Mike,
You got a handle on it. If the new gasket has no data with it you follow the jeep manual. The jeep manual DOES NOT SAY ANYTHING ABOUT USING ANY SEALANT.

I use Ole Permatex #1 on just about everything. It took care of my head bolt and stud threads in water jackets since the early 60's with no problem. There are a dozen choices now in sealants advertised especially for head bolts/studs and even Permatex has one.

The advice on using sealant coming from modern engine shops comes with a familiararity with more modern engine and higher performance engines and engines with dis-similar metals. Just follow the factory's manual on these old engines. If you don't get the head and deck resurfaced make darn sure you measure for waviness very carefully and at least rough the surface to the necessary quality for bonding.

Wes. In using the hardening type 1 Permatex, would there be a time limit on how soon you start the engine and shutdown for retorque. My peas size brain is thinking the stuff would harden and then when you move the bolt again, you would break that seal, unless you did this real soon. I am also thinking it would take a little longer while inside the engine to harden but is it an issue?

And thanks again for taking the time to post the links and get me further along in my apprenticeship.

Mike

If you install the head, fire it up and then retorque within say 2-4 hours I don't see any hardening issue. On the other hand if your engine is out on the stand you may not beat the time. This is one good reason to use studs instead of bolts.

I am going to proceed under that assumption that I screwed up applying the sealant to the gasket when it was not called for by the manufacturer. That's in addition to anything else I might find. The web sites that Wes provided are very educational and I want to see if the Felpro Perma Torque gasket might be available for this engine, but I think not just based on demand. I still might consider the Felpro just to change my chances.

The Felpro is available thru NAPA locally but some of the gaskets I need will require additional charges for shipping so I am going to check with other vendors as well.

As for using Permatex No.1, the hardening type, there is no way I could get the engine up and running in 2-4 hours after placing the head gasket like Wes can do. But I got it torn down in 4 hours. Does that count for anything?

I will look for the other sealants available for head bolts.

Mike

I'm not that good. Up and running in 2 to 4 hours assumes the engine is already in the jeep.