Hello everyone. My grandfather has a 1986 C4. I know the valve covers are leaking oil pretty bad and i want to help seal them up. I have heard that i should just replace the seal with a new cork one and then i have also heard that i should just use silicon because the cork will break down in less than 2 years. Can anyone offer me some advice to what the best method would be to re-seal the covers? At this time I am going to try to keep them stock unless i pull them off and see that they have begun to pit. Thank you to anyone who can help me out.

 

Search for the thread that was on here recently concerning the early C4 valve cover sealing it was very informative to me as I have an 84 and 86 that both have minor leakage........Jay

 

My Advise would be to use Silicone without the gasket and lay a 1/4 inch bead and first make sure everything is grease free,clean and dry. Lay a real nice bead on the valve cover and then put it straight down onto the motor without sliding it from side to side. Let it fully cure according to what it says on the tube and you'll be set

 

An 86 will have centerbolt rocker covers.

They use a very good silicone rubber gasket and the cyl heads have a nice machined rocker cover surface.

Buy new Fel Pro gaskets, clean the rocker cover and the cyl head off good and install the new gaskets dry.
Will

 

There ya go You have both worlds I {me} that likes Silicone and the other side that likes the factory Gasket. I like the Silicone because it sticks/glues the cover down and its cheeper and I always have a couple of tubes around and dont like the gaskets because they don't come with lots of holes with steel cone inserts to stop slipping out when tightened

 

Hi the 86 vettes have an early and late version, the early ones had the cast iron heads the later centerbolt aluminum heads.

NFSMANIAC Check what type heads you have, you are correct with the cork gaskets they are pretty bad. The main problem is the valve cover and head have a bit of a mismatch the cork gaskets will be cut if overtightened and you may find that when you remove them.

I have the metal reinforced rubber gaskets, they do not leak.
Be carefull that you do not trap any wires while fitting, tighten them down and you do not have to wory about valve cover gasket leaks aver again. I reused them on my new 383 engine.
She does not leak a drop of oil.

You can get rubber gaskets for the centerbolt valve covers also

http://www.ebay.com/itm/Chevy-SBC-350-1955-85-Blue-Rubber-w-Steel-Core-Valve-Cover-Gasket-Set-/201120739098?pt=Motors_Car_Truck_Parts_Accessories&hash=item2ed3baef1a
http://www.ebay.com/itm/CHEV-SB-283-307-327-350-400-VALVE-COVER-GASKETS-RUBBER-PERMALIGN-MOROSO-93020-/161372021095?pt=AU_Car_Parts_Accessories&hash=item259285a167#ht_1324wt_684
86-91 type below.

http://www.ebay.com/itm/Chevy-SBC-350-1986-97-Black-Rubber-Valve-Cover-Gasket-Set-/181454990584?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a3f8f6cf8#ht_21037wt_988

 

Thank You Everyone. I think I'm going to attempt to use the rubber gaskets bc i have a feeling id get the silicon everywhere! But I'm glad the cork has been ruled out. Thank you all for the help

 

Mine doesn't. Mine are cast iron (built in December 1985). The center bolt valve covers were used with the aluminum heads. The aluminum heads weren't introduced until the convertibles came out around April 1986 or so. After that all engines had the aluminum heads.

 

Does the engine have center bolts or perimeter bolts for valve covers???

 

This is the first question the OP should of been asked, because what works on one , won't work on the other.....If he has centerbolt covers the blue silicon gaskets are the way to go, if he has perimeter bolt covers the blue silicon gaskets are not going to work very well..The best method for the perimeter bolt covers is still to use RTV to seal them up, like suggested in the factory service manual..............WW

 

Don't rule out the cork just yet. I replaced both of my early 86 valve cover gaskets with the felpro permadry gaskets. One side sealed perfectly, the other was a nightmare. It would not seal for anything. I tried from finger tight to 70 inch pounds and nothing worked. The problem was the valve cover itself. The casting was so bad in one spot it would not seal. I used cork and siliconed it to the valve cover. Before it set up I placed it on a flat floor and put a weight on it and let it sit there a day. The gasket was now sealed to the valve cover. I installed the valve cover and have had no issues since.

 

Thats a good way too to use the silicone

 

I went through the same situation with the PermaDry gaskets. I finally fixed it by smearing a little RTV on the gasket surface around the valve cover studs, both on the valve cover and the head.

 

Mine has perimeter bolts. Its not a convertible either so I'm thinking the covers are the cast ones.

 

Hey there thank you for this post. This was very informative. I do not have the factory service manual and now that i know the service manual says to use the silicon i will go that route. The car does have perimeter bolts not the center bolt so thank you ill give the silicon a shot

 

just a reminder, make sure both mating surfaces free from foreign matter (old gasket material, old silicone, etc.) and are squeaky clean. I mean SQUEEKY clean. go over both surfaces with cleaning solvent several times, and then go over them again. lay a bead (about 3/16") of silicone on the groove of the valve cover, and position the cover. finger tight on the mounting hardware for about 1/2 hour, then torque to spec. let it cure for 24 hours - engine heat does NOT fast cure this stuff. (FWIW, and my 2-cents) that's pretty much my procedure, and I've never had an issue with silicone on iron head VC's.

 

Thank you i have been reading up on how to get these things clean. I know they need to be perfect!!! What solvent are you using to clean you covers. I have read that you can start with a razor blade and get the chunks off and then use brake cleaner or something to get the rest. Will brake cleaner work or is there something better?

 

I've mostly used lacquer thinner. I would guess, any solvent based product should do the job.

 

Fel Pro gaskets are the right way to go.

However, before you tackle this project, start by carefully re-tightening the four (4) valve cover center bolts. These bolts have a torque spec of only 8-10 ft. lbs. Due to the constant hot and cold condition and the incessant vibration of the rockers, the L98 valve cover hold-down bolts tend to loosen up and cause leaks. Soooooo, try retightening the 4 bolts first, but be very careful not to over tighten them.

Going forward, I suggest that you retighten your valve cover bolts every month or so. Its an easy job and only takes 5 minutes to get it right.

FWIW,

P.

 

If you read Post #14 the OP states he has perimeter bolt heads , he can't use the Felpro gaskets on those....WW