valve cover leaking

[t-mark]

I recently had the gas tank off on my "63 4000(172ci) so I decided to change the gasket on the valve cover while it was easy to get to. Well, sure enough, now it leaks. Anyway, I just wonder if anyone has any tips. The new one is the rubber(neoprene?) type. All surfaces seemed to be clean when I put it back.
Should I use anything with the gasket to make it seal better?
It seems to be leaking towards one end of the cover. Does anyone know what the torque is supposed to be on the two hold-down bolts? Is it possible that they"re too tight causing the end to bow upwards?

 

[Anonymous-0]

Remove cover & lay it on flat surface to see if the ends are not streight with the rest of cover. If it is not setting down all way round hit it with hammer or block of wood till it is sitting down flat. I glue the gasket to the cover with contact cenent so it will stay in place while installing it. I put Permatex Aircraft sealer on other side of gasket & install . I dont know about torque but dont tighten too tight to start out If it leaks after running you can tighten sone more

 

[GlenIdaho]

T; For a 800 or 801 172CI the rocker arm cover (valve cover is on the side)is torqued to 1 1/4 to 2 inch pounds. So, you can see that if you put some torque on them they can be tweaked. I would imagine the torque would be the same for your 4000. Hope this gets you in the ball park.

 

[RodinNS]

Dunno on that cover..... but on the others I've used the neoprene gasket on, the only time I had trouble is if it was unevenly or overtorqued. I dunno the spec for that one, but you need it.
I don't put any goober glue on them. Just the gasket, and then it's reusable.

Rod

 

[Dean]

T:

The other earlier posters have given you good advice.

My experience has taught me that leaking valve covers are most often caused by deformation of the sheet metal cover due to over tightening of the fasteners either upon your latest replacement of the gasket or at some earlier time.

That said: Cork gaskets are more forgiving with respect to compressive forces than are neoprene gaskets. If someone in the past overtorqued the bolts deforming the cover in some way but used a cork gasket it may not leak for a long time, perhaps until you subsequently removed the cover. If you now (unknowingly) installed a neoprene gasket with a deformed cover you may have a serious leak on your hands.

For this reason, I prefer cork gaskets. Usually I seal them to the cover only so that I can remove the cover, gasket and all, if necessary. If the bolts are not overtorqued, cork gaskets can usually be removed and resinsalled several times without creating leaks. This is handy as it is often necessary to do this so as to retorque a cylinder head, etc. Neoprene gaskets are not so forgiving in this respect.

As the other posters have already advised, check your cover for straightness and repair it if you can.

As a last resort only: You can probably get by with a badly deformed cover and plenty of silicon gasket sealer on both sides of a new cork gasket, providing that you have thoroughly cleaned both surfaces before applying the silicon. (Tip: Use gasoline or brakd cleaner to clean the oil residue.) If you use this technique, hopefully you will not need to remove the cover to retorque, etc. You will have a mess on your hands if you must.

Dean

 

[t-mark]

1 1/4 to 2 in. lbs? That doesn't sound like much torque at all. I'm sure I have a lot more than that on it. Maybe that's my problem.

 

[t-mark]

Thanks for all the good advice, guys. When I go see Ol' Blue next weekend I'll have to determine which nuggets of info I'll have to use.

mark

 

[GlenIdaho]

T: Yeah, I was surprised too when I looked it up in my manual. Like I said, though both engines are 172's your's may be different.

 

[t-mark]

Glen, where did you find the spec. I looked in my owners manual and the IT manual and coudn't find it in either. Maybe I just didn't look in the right place.

mark