Valve cover gasket issue.

66Hardtop

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And it's leaking again. It keeps blowing out between the 2 bolts towards the back with the 2 cork ones I've tried. Trying the rubber ones again.
 

The Goose

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Or pull the cover and hammer flat all the bolt holes. Like was said a few posts back, over tightening will collapse the valve cover holes and it’ll never be right. Tiny bit of silicorn on the valve cover bolt might keep it from backing out if they’re vibrating loose. Good luck I use cork never an issue.
 

jcloving

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Here is my procedure for valve cover gaskets/oil pan gaskets:

Purchase felpro silicone gaskets with bushings at bolt holes
Purchase new tube of permatex ultra black
Clean valve covers thoroughly, especially sealing surface with solvent. Straighten/flatten if needed.
Clean head sealing surface with solvent.
Apply thin bead of silicone to valve cover and install gasket.
Apply thin bead of silicone to head sealing surface
Install valve cover with gasket and tighten bolts till just snug.
Sleep on it.
Next day, tighten valve cover bolts to torque spec.

The silicone will "glue" the valve covers down to the head but it will keep them from leaking. I rarely remove my valve covers anyway. When I do a dead blow hammer helps.

No leaks.
 

Newport 66

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I just got a set of 4 bolt valve chrome valve covers for my max wedge project and spent about 2 hrs peeling the old silicone gaskets off of them. The previous guy had gotten carried away with the black RTV sealant. From the looks of the covers they were leaking anyway.

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66Hardtop

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I ended up buying a different cover. After checking it my original one was warped pretty bad. All is well now with a new Fel Pro rubber gasket. One of the bolts cross threaded and when drilling it to put a helicoil in I hit the water jacket but got that sealed up nicely and a fresh oil change.
 

BillGrissom

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Leaks from the rear of the valve covers have driven me crazy for years on my 1965 Newport. The problem appears that the heads don't have a flat sealing surface. It is a rough casting and drops away ~1/8" at the rear. I have negligible blow-by (new short-block & restored heads), so the crankcase even runs at a slight vacuum w/ the PCV. I have tried everything, including the foam silicone sealant, yet it still drips oil onto the starter. Last pass, I tried Real Gasket, which is firm silicone, under a cast-aluminum Holley valve cover. I thought to first try tightening it more at the rear to insure the gap is closed there. As I tightened the forward nuts, the ear on the rear of the cover snapped off, ruining the cover. The surface is that non-flat. Now that I have a milling machine, my "final solution" is to remove the heads and try to mill a flat surface all around. That may put the interface below the oil level, but shouldn't matter. I will also mill off the casting line which tends to stop oil from draining back. I tried that before w/ heads on engine, being careful to collect all shavings (stuffed rags & vacuum). If I botch the heads, I will switch to aluminum heads, which wouldn't be a terrible result (save ~50 lb).
 

BIGBARNEYCARS

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Bill, Big-M Automotive iz only an hour north of you in Williams. Call 'um at: 530-473-2225 and tell 'um what head # you need. I'm not sure what head Mother used on the '65s?
But more then likely Williams will have it. Way easier then going thru' the machining process. Then re-use the "RED" Real Gasket from Tennessee after you've cleaned it up and torque to their specs. 16 in. lbs. if I remember right? But it goes on DRY per their instructions. No better gasket on the Planet. Just look at what they produce for the Air Plane Industry. Brake Clean spray can on the head and the rocker cover mating surfaces if you want it clean and dry. It'll only take ah minute to evaporate, Jer
 
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PatinaPolara

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Having read the above thread AFTER buying new valve cover gaskets, (fel-pro vs 50145R) I was wondering if there are any tricks for installing on my original 383 2bbl. My previous corks were leaking badly and parished, the original valve covers needed a bit of straightening, and original head has similar rough casting edge mention earlier. Should I use any adhesive?
 

Rustyrodknocker

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Having read the above thread AFTER buying new valve cover gaskets, (fel-pro vs 50145R) I was wondering if there are any tricks for installing on my original 383 2bbl. My previous corks were leaking badly and parished, the original valve covers needed a bit of straightening, and original head has similar rough casting edge mention earlier. Should I use any adhesive?

I try not to use adhesive until I'm going insane.
It can be a nightmare to get them off and damage is probable if they are stuck hard.
If you do use it keep it thin and spread it with your finger. You don't want a blob coming off on the inside. Cast aluminum seems to hold better if you can handle the look.. As posted before the finished surface can be terrible. Its the most disappointing thing on a big block to me. Two more 1/4 20 screws and a finish pass on the head would make those motors so much better.

I have been using the think graphite impregnated
Fel pro. They can be hard to get the screws started when new. And require a couple retourques but they work for a few years. I have a new set waiting
Mine is leaking in the rear. I can always smell the oil cooking when going up hill.
 
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