Sealing Stamped Small Block Valve Covers – Grrr

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pntastar69

pntastar69

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I will be going on my 4th set of valve cover gaskets on my 360 w/stock stamped VC’s, not the chrome ones. Dealing mostly w/seepage. I initially had the Moroso Blues on when I primed the engine and it leaked out of the right bank, middle hole on the exhaust side. Switched to Felpro corks, 3M snotted them to the VC and after several local jaunts, it was seeping on the exhaust side front and middile hole. Scrapped off all of the snot and went w/the Mopar black, hardened pcs and same results. And no, I did not over torque them, just hand tightened them. So I took them off again, scrapped all of the snot off and started checking for straightness. I managed to get the rails even and hammered the mounting bossed as they were sunk too low. The picture shows a ruler on the rails and the gap between the ruler (rail) and the mounting bosses.

Should the mounting bossed be flush w/the rails or sunken as seen in the picture?

Second question: If I get them straight, what gaskets should I order? The Mopar rubber w/steel cores are awfully expensive but I guess you pay for what you get.

VC1.JPG


VC2.JPG
 
I used the Moroso steel core gaskets, they fill in the gaps the best, in my opinion. I am surprised that you had some issues, but we all have seen different things work and not work.
They are on the high side but works.
 
Steven190 said:
I used the Moroso steel core gaskets, they fill in the gaps the best, in my opinion. I am surprised that you had some issues, but we all have seen different things work and not work.
They are on the high side but works.
Click to expand...
I had the same problem only w/ cast mopar covers. They are way more ridged than stamped too! header heat on my raised port heads burn them around the center cyls. I had to got to the expensive ruber/steel reinforced gaskets, wrapped the headers,and built a header wrapped guard
between the valve covers and the high header tubes (big block )
 
pntastar69 said:
So I should hammer down the bolt mounting surface closer to the rails?
Click to expand...
Yes.
They should be flush with the rest of the rail and straight all of the way down.
I will NEVER use cork gaskets again, i only use the neoprene (rubber) ones and use Gasgacinch on them.
Another note is to clean the rails and head surfaces so they are absolutely clean of any gasket material and oil.
 
I went through similar problems as you. Are you using thread sealant on the cover bolts? That solved leaks I had on both the lower firewall bolts on each cover. I then used a lot of Gasgacinch on both sides of the cork gaskets. Sounds like your using something similar with 3M. Also found it was weeping out along the cork tabs that place/hold the gasket in the cover. So covered the exposed cork tabs with snot (it dries almost clear so it’s not noticeable). I tried the steel core rubber gaskets (Mopar Performance ones) but still had several leaks so they are hanging up in my garage. I suppose if I did the same tricks with snot and thread sealant on the MP gaskets they might not leak now?
 
V/covers, oil pans and trans pans- always straighten the sheetmetal before re-installing. For stock v/covers, I do the gorilla snot thing as you describe with cork/rubber gaskets. Always put silicone on each bolt/stud as they tend to leak. All this being said- v/covers are problematic.
 
Like Steven190 said. I too use the Moroso rubber/metal shim on factory metal VC's. Had the covers on and off a few times reusing the gaskets with no issues. Eddie heads. Had a few leaks when I was using the cork composition gaskets. Pay a little extra and be done with it.
 
What is the part number for the Moroso rubber/metal gaskets?
Forgot to mention, these are iron heads, not aftermarket.
 
The old LA heads with as-cast V/C mating surfaces definitely don't help, I had a set of vintage cast Mickey Thompson covers on Magnum heads on my 360, just used regular Fel-Pro cork gaskets with no other sealers or chemicals and they never leaked a drop for years. Machined cover rails FTW lol...
 
That cover needs to be flat and true. It will never seal with 5 bolts if it isn’t flat. To save that cover, you’ll need to straighten it nicely or apply some 2 part epoxy like jb weld and finish it til it’s flat.
 
Update: after several hours of hammering and straightening the VC's and installing the grey mopar rubber ribbed steel core gaskets, the oil leak has ceased. Thanks all for your replies.
 
pntastar69 said:
So I should hammer down the bolt mounting surface closer to the rails?
Click to expand...
NO!!
Think about it.
If you hammer down the bolt areas you just made a torque limiter........ in the wrong place. With the old style impregnated-cork gaskets the idea was to tighten down the cover until that space contacted the cork, then a little more preload. This compressed the soft cork the right amount to seal properly.
This also holds true for the silicon gaskets and the other non-torque-limited types.
But not for gaskets with torque limiters and those ignorant hard black I-don't know-they're-made-of, ones. On those I pile a little RTV around the bolt holes on the cover to take up the space,and then no RTV on the bolts; it makes clean up a little easier on subsequent inspections. I try desperately not to use those hard black ones.
OK, you could pound the bolt areas down for the torque-limited gaskets, if you really wanted to, but not on company time,lol.
 
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