leaking valve cover gasket

leaking valve cover gasket

elwood blues

Always Off-Roading Jeeper
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Location
Export, PA
Vehicle(s)
1978 CJ7 4.2L Comp Cam & valve train, MC2100 carb, MSD ignition, Dana 30 front, T18 trans, Dana 20 txfr, AMC 20 rear.
Okay everyone, I need some help. I'm really stinking frustrated :bang:. A couple of years ago I picked up an aluminum valve cover looks like this one

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Here's the problem, this valve cover comes with this gasket

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the '78 valve cover gasket looks like this

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When I replaced the plastic valve cover with the aluminum one I used the gasket that came with it. It leaked at first, so I took it back off and put a very liberal (read a :dung: load) of black permatex gasket maker. I got the leak semi-sealed, and I just dealt with the oil that kept seaping out.

Well, I had taken the valve cover off to check the ticking noise that I hear. Long story short, when I put the valve cover back on I bought a valve cover gasket for my head (1978). Thinking that I might be able to get rid of the leak. Well, I installed the new gasket with a liberal amount of permatex, but it freaking leaks like a sieve now. I litterally have oil on the front axle now. WTF? Anyone have any ideas? Thanks everyone :chug:
 
Elwood you have kicked over an ant hill now!!
I bet there are going to be at least 10 ways to skin this cat!!

IMO, for what it is worth, valve cover gaskets leak and the sun comes up in the morning in the east. That is the law!!

Now for the best I have ever done with this problem, I use high temperature RTV not Permatex.
1) pull the cover and clean it, the edge mostly, you don't want oil dripping on the surface you are trying to seal with.
2) clean the edge of the head where the cover will set, once again the object is to not have oil in the seal area when you tighten the cover.
3( put a bead of RTV on the sealing edge of the cover about 1/8 to 3/16 inch, let it stay round, don't spread it with your finger. The object is to form something like an "O" ring on the cover. Now go to the beer store of watch TV for an hour or so depending on the weather. You want the RTV to "Scum” over you can touch it with your finger but it does not stick. It isn't too bad if it is even a bit firm to the touch. This also helps when you put the cover on, I always have a problem clearing the last rocker with the rear of the cover, and if it is firm you are not so inclined to mess up the seal.
4) After it is on put the bolts in and run them down finger tight, make that light finger tight. It is only going to take about 5 inch pounds of torque to seal this. In fact too much torque and not cross tightening the bolts will make the cover leak faster than just about anything. So slowly cross torque with a socket on an extension and don't use a ratchet at all I think that after you go around 4 or 5 times it will be snug and not over tightened
5) You will notice I did not use a gasket at all. and hopefully you will notice that, because you let the RTV set up quite a bit before you put it on that it did not "glue " itself to the head, requiring screwdrivers crow bars and paint scrapers when you need to remove the cover next time.

Be advised, this will give it up after a while. I think 50 or 60 K miles are about par and you can do it again.
It is the best I have been able to do.
 
I find it strange that the gasket that cane with the cover is the wrong shape. Does the cover have the same shape as the head, if not it will never seal.

And by the way I also use RTV in the same way as IOPort51.
 
RVT - Place a bead on the cover, place a bead on the block, let them tack up - then mate them... :) Do not over tighten!

Works for me! L(
 
Thanks you guys. At least now I have a plan.

Old Dog, the more I research parts and general reading that I do, I'm finding that AMC changed almost everything right around 1980. I have no clue to why, but it seams that every system that I look at, engine components, brakes, transmissions, doors, right around 1980 changed. And to answer your question, no they aren't identical, but they overlap, so I think I can make it work.
 
they look a lot more alike if you flip one of them over.:chug:
 
I still use the original plastic cover with a Fel-Pro cork gasket and it's dry as a bone, always has been. Aluminum one's are neat, but too expensive for my blood.

I will reveal my secret for money or a set of six bolt disc brake hubs

Paul
 
So, I went digging through my garage and found my stock (metal) valve cover. Took it to a local auto machine shop and had it acid cleaned. I stopped over and picked it up today. They did a great job, took it right back down to bare metal. Got all of that old grime out of the baffles and everything. Anyway, my question is, do I need to use high temp engine paint on a valve cover? Or can I just get away with rust-o-leum?
 
No need for Hi-temp paint. It's all in the prep work. Wipe it down with lacquer thinner, prime it and paint it (two or three coats, let them dry thoroughly in between. Rust-o-Leum is fine and should last for a long time. I prefer Krylon paint and would probably use a satin black. If any of the holes are pulled down, beat them out level. If they are depressed they give a false torque reading and make the cork gasket deform and, you guessed it, cause leaks.
 
I had the same problem as you in my '80 CJ5 , AMC 258 i6 / 4.2l . I used RTV Black, Red, and blue, with and without gaskets and never had good results. A mechanic recommended the "Right Stuff" with no gasket. Apply to both surfaces, let set 5 minutes then place and tighten the valve cover, not to tight. I did it and have been dry as a bone for 6 months now. The "Right Stuff is not oil based and did a super job. It is not that expensive and since you don't need another gasket it's a fix worth trying. I was skeptical at first but the results speak for themselves. Personally I would like to see someone else try this and tell us all the results. If it is verified by someone else, it would sure make an easy and cheap fix for everyone with this problem and I don't know many that don't have this problem with this engine.

Tommy
 
Yeap, it's made by Permatex, it's as good as advertised.


41PX016yh9L.jpg
 
I got tired of my AMC 258 i6 / 4.2l valve cover leaking....so I replaced it with a 401 :D
 
I just had to do the lifters on my ford 390 BB ( 3 bent push rods) and i just got the felpro rubber gaskets, and didn't use any RTV for the main reason the temperature was the outside ambient temperature of more than likely 10-20 degrees and that's not a proper temperature for it to vulcanize and i know they will seal well enough anyway without RTV.
 

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