5 bolt valve cover leaks

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swifter

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I know welcome to the crowd with valve cover leaks but I welcome any helps,I tried buying the moroso rubber gaskets sandwiched with steel inserts but we still get leaks on the lower corners(firewall side),Covers are fabricated aluminum,So any suggestions would help,Should we go back to cork????? I put the gaskets on dry like the instructions said would rtv help or is that a no-no--Thanks Steve
 
steve, what valve covers do you have? also, are they machined flat on the bottom or do they have the gasket groove around the bottom.

every leaker I have always had was an easy fix with the moroso gaskets that you spoke of. so much so that I just started using them to start with.

I have the fabbed aluminum Mancini valve covers and have had zero leaks with said gaskets on them.
 
set the valve cover on with out the gasket. you may find that its the intake that's holding you up and causing a leak.

Grind cover and or intake to fix problem.
 
Are you running cast iron heads by chance?
Stock heads are arched front to back and fabbed covers are straight, so it makes it pretty interesting to seal them.
 
Cudafever said:
set the valve cover on with out the gasket. you may find that its the intake that's holding you up and causing a leak.

Grind cover and or intake to fix problem.
Click to expand...

Definitely check this ^^^^. I have the cast aluminum Mopar Performance valve covers and they hit the intake runners, causing massive leaks. I had to grind out notches on the valve covers for the intake runners, now they fit perfect with no leaks. I have always joked that NOTHING on my car fit properly out of the box...even parts made by Mopar needed grinding to fit, LOL!
 
Yep cast iron heads on a 360, yes fabbed alum covers with no groove just a flat on the bottom -thanks steve
 
And its only on the back corners so we will check without gaskets and report back
 
So would cork gaskets be a answer cause they account for irregularities ???? Thanks steve
 
clean the VC up and place it on a flat surface to make sure they are straight if not them take to a machine shop to put on a belt sander to straighten them out.
 
First - the fabbed covers can be really be in terms of flatness. Second - the intake can interfere as noted above so check for interference where the covers go past the tops of the intake ports. Third - because there is no flange to help retain the gasket - I'd glue them to the covers with weather strip adhesive prior to installation on the engine, and yes - I'd only use cork for them. No RTV. Tighten evenly and moderately to avoid warping the covers.
 
moper said:
I'd only use cork for them. No RTV. Tighten evenly and moderately to avoid warping the covers.
Click to expand...

I was hoping if they hit the intake like mine did he would notice that pretty easy, and he doesn't have a leak on that side so probably not the issue.

Cork haskets won't do it, been there
Gluing them won't
Tightening the hell out of them won't
Making sure they are flat won't

The problem on factory style heads is that the rail has an approximate 1/8 arch to it front to back and the cover is straight. (without the gasket set it on and push down on the back of the cover) the front pops up about 1/4 or more.
Same if you push down on the front (the back pops up 1/4 inch) and it's not warped valve covers.

I did mine exactly the same as Swifter is doing and mine are dry as a bone in the the AZ desert, but if I tell how I did it in a public post there will be a shitstorm of posts saying how stupid my solution was, how it couldn't possibly work, or that I should spend a bunch of money on machining so I can run Fabbed covers on stock heads that I don't even need. (I have stock heads and valvetrain) and I did it for the look and possibly needing them on a different motor because I got a GREAT deal on them.

This was before I put the headers on about 8 months ago, and they are still bone dry, so it can be done.
As long as you accept and deal with the arch of the valve cover surface on the factory head.
 

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There sure does seem to be a lot of resistance to the facts on this.
It is easy to blame it on over tightening, or being to dumb to put valve covers on correctly, but the only way this is going to change is if they can't sell them.
And the only way they are not going to sell them is if this kind of information gets out there to possible buyers.

It's possible that they already don't care what the BB cover reputation is because it's not worth the sales amounts.
 
Thanks Guy's looks like I'm not on a island by myself !!!!!!!!! Steve
 
I had 3 sets of the Mopar Performance valve covers and I have never had any of them leak. I have used different kinds of gaskets but I like the rubber ones and glue them to the valve cover. I just snug them down , you do not need to over tighten them.
 
I've never had a MP valve cover leak either..... but that comes down to my dead selection. Stage VI, W5, W8 :) nice wide FLAT surface for the cover gasket to seal!
 
Well after looking closer sat. I think i got it but wont know till we run again, the towers for the bolts measured 3-3/4 and when i screwed the bolts in without the cover on it measured from the head to bottom of bolt 3-3/4 so we added two small washers under bolt head for more clamping pressure on the gasket and also put a skim coat of ultra black between gasket and head-steve
 
I have B1 heads, I am pulling off the valve covers a lot. What I do is: Glue a rubber style casket to the valve cover side with rubber trim glue. Then believe it or not I use front wheel bearing grease, for the head side. I doesn't leak. I have tried vasaline but I needed it else where! It was actually thinning out with the heat. You don't need a lot of grease either. MAKE SURE you have a good e vac system or breathers or a pvc system. Using an off set Master Cylinder plate from Mancini sure helps for big block valve covers to go on and off. I have used this valve cover gasket idea for 20 plus years. Good Luck.
 
Great idea with the grease i know we are also fighting with a lot of crankcase pressure, the breathers were oil soaked so i cleaned them real good so hopefully that will help, we have breathers on both valve covers-thanks Steve
 
Yep made 6 runs Friday night not a drip !!!!! Yea thanks for the help men-steve
 
having same problem with my new rebuilt 360 with MP valve covers , its a dam oil bath under there . new plan tommorro after reading this if that doesn't work , going back to 273 valve covers if they fit over my roller rockers
 
My X heads love to leak with the MP Performance \VC.... so I notived the grooves on the LD340 intake interfered with the seating of the VC. So I filled the part where it touched bit by bit until there was no touching when gasket was on.... Voila no more leaks... Used the black rubber MP performance gaskets....
 
winstoninwisc said:
having same problem with my new rebuilt 360 with MP valve covers , its a dam oil bath under there . new plan tommorro after reading this if that doesn't work , going back to 273 valve covers if they fit over my roller rockers
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They won't ... unless you modify the welded baffles.
 
TrailBeast said:
I was hoping if they hit the intake like mine did he would notice that pretty easy, and he doesn't have a leak on that side so probably not the issue.

Cork haskets won't do it, been there
Gluing them won't
Tightening the hell out of them won't
Making sure they are flat won't

The problem on factory style heads is that the rail has an approximate 1/8 arch to it front to back and the cover is straight. (without the gasket set it on and push down on the back of the cover) the front pops up about 1/4 or more.
Same if you push down on the front (the back pops up 1/4 inch) and it's not warped valve covers.

I did mine exactly the same as Swifter is doing and mine are dry as a bone in the the AZ desert, but if I tell how I did it in a public post there will be a shitstorm of posts saying how stupid my solution was, how it couldn't possibly work, or that I should spend a bunch of money on machining so I can run Fabbed covers on stock heads that I don't even need. (I have stock heads and valvetrain) and I did it for the look and possibly needing them on a different motor because I got a GREAT deal on them.

This was before I put the headers on about 8 months ago, and they are still bone dry, so it can be done.
As long as you accept and deal with the arch of the valve cover surface on the factory head.
Click to expand...

This is the problem, the valve cover rails on SBM and BBM are almost never flat,they have a serious arch in them preventing them from ever sealing with a cast valve cover that doesnt flex like a stamped cover. I mill the rails flat and it takes care of the problem every time.

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CudaChick1968 said:
Yayyyyyy, more leaky and defective valve covers!!! :-(

Here ya go boys and girls ... read up on the "crapsmanship" I've been discovering on aluminum MPs.

http://www.forbbodiesonly.com/mopar...ck-MP-Valve-Covers-Please-Read-This-and-Share

So far, more than 60 OWNERS have reported similar or worse problems. Yikes ...
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Your photo clearly shows what happens when people try to crank the snot out of the bolts in an attempt to get them to seal when the heads themselves are the problem and not flat. You can't make cast aluminum flex and not expect it to crack exactly like in your photo. Its an obvious problem when you take the time to look instead of blaming QC at MP.
 
Take the time to look at my other thread -- showing the exact same crack in BRAND NEW MP VALVE COVERS -- before you toss out accusations against my customer.
 
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