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valve covers keep leaking after replaced

pjm8047

pjm8047

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My valve covers are driving me crazy.I just installed some used nos valve covers from a 1970 440 engine 2 weeks which were in great shape. i replaced them because the old ones got over tightened and broke through the bolt holes.So when I installed the new ones I put rtv on both sides of the valve cover gasket and I was still leaking oil from the bolt holes of the covers on to the exhaust manifolds causing it to smoke.I used the torque spec for the bolts from the 71 plymouth service manual which was 40 inch pounds.So I decided to remove the bolt and put rtv on the bolts.When I removed the bolts i noticed that the valve cover bolt hole had broke through again!!Cheap NOS covers?My question is what should I do now buy chrome steel covers and use tabs on the bolt hole? if so I cant find any that have the breather and pcv valve buffles torward the back of the motor.Im lost
 
Did you allow the RTV to cure first THEN tighten? The torque specs are probably for cork gaskets.
 
I only use now either fabricated aluminium or cast aluminium covers with the nice thick flange, never had a leak here.
no good if your going for a stock look.
what gasket do you use? stay away from the cork and try the thick fibre ones with steel insert.
 
69Runner said:
Did you allow the RTV to cure first THEN tighten? The torque specs are probably for cork gaskets.
Click to expand...
No I did'nt.

- - - Updated - - -

i used these gaskets
http://www.autozone.com/gaskets/valve-cover-gasket/felpro-valve-cover-gasket/plymouth/roadrunner/1971/8-cylinders-n-6-3l-4bl/72303_206731_15973/

- - - Updated - - -

i was thinking about buying these but not sure if they'll do the job.I dont really care about looks at this point.
http://www.ebay.com/itm/380224223431?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
 
factory 440 v/c are a bitch, I cut some little triangles of sheet steel and weld them in, but you can just grind some large washers to fit in there and not weld them, I fit the little triangles in and then repaint everything its hard to tell they have been changed.

I use the fel pro 1612, they are like $20... If I run across a problem set of valve covers I use the steel core morosos, they are like $50 BUT do NOT leak...
 
Stamped steel valve covers are prone to leaking. Most are the result of over tightening. I see you've taken precautions for just that. Along with the good information above you could try studs instead of bolts. They will allow you to align the gasket on the head better. You could also use washers that are marketed for valve covers. They will spread out the pressure and lower the possibility of damage to the holes and flange.
VC washers.jpg
 
Shorthorse said:
Stamped steel valve covers are prone to leaking. Most are the result of over tightening. I see you've taken precautions for just that. Along with the good information above you could try studs instead of bolts. They will allow you to align the gasket on the head better. You could also use washers that are marketed for valve covers. They will spread out the pressure and lower the possibility of damage to the holes and flange.
View attachment 276116
Click to expand...
Little too late for that i guess.new valve cover suggestions?
 
I want to find some that can use the factory breather and pcv valve because of the gas tank vent line.do i really need that vent return line?
 
I've seen heads that had a poorly cast gasket rail too and leaked no matter what kind of a VC was installed. It can really make you chase your tail and is very frustrating. Do a close inspection to make sure you don't see any casting flaws anywhere along the rail.
 
Did someone say casting flaw? I made a career out of stopping my aluminum fabricated VC from leaking. I overtightened in the pursuit of stopping the leaks, bent the VC, had them plained. In the bitter end I found a casting flaw. I ground it down and I put 'The Right Stuff' sealant on the gasket and a little on the bolts for insurance. No more leaks.



Head Nub.jpg
 
These leaked at the drivers firewall. Took months to figure it out. I'd prefer the factory look. Suggestions? I gave mine up because they were for a 70 and traded for these. You need a thimble to add oil and they look scratched like **** most of the time. image.jpg
 
I think the only covers I will use in lieu of the factory models are the mopar cast aluminum ones... I just think they are overpriced.. There was a company that made fabricated covers and milled covers, they would write what ever you wanted in them, not sure if they are still around
 
Where is the best source for factory covers?
 
I have a set of powder coated aluminum Mickey Thompson valve covers. Used the Felpro cork gaskets, but did not use any rtv. Used Permatex "Indian Head" shellac to hold the gaskets in place on the covers before setting on the heads. Let everything set up nicely before placing/tightening. I don't recall the pounds recommended for tightening mine down, but 40 pounds seems high. Not had any leaks all summer. -- 74 Charger with 71 440 4bbl --
 
[h=1]Hamburger's Performance Fabricated Aluminum Valve Covers 1052 with a morsco rubber gasket. Works well for me.[/h]
 
if I dont use the stamped ones, I rock my V/C's from Leanna...aka Cuda Chick :headbang:

VC's after 6.JPG

VC's after1.jpg
 
Just remember this:
Valves Covers are either made for iron heads OR Aluminum Heads.
Valve covers made for iron heads will leak when used on aluminum Heads
and
Valve covers made for aluminum heads will leak when used on Iron Heads
....REASON...
The "studs" that come out of the head are on a different angle for iron OR aluminum heads...which also means, if you use "bolts" to fasten the valve covers rather than the studs, the the bolt are going into the threaded holes at the wrong angle.
THE ABOVE IS A FACT AND CANNOT BE QUESTIONED.
If you are using the correct valve covers for you head, iron or aluminum, and then the leak it is then merely the "seal" the gasket is, or is not making, onto the head, then the gasket comes into question. Personally I used the top of the line rubber gasket with the steel inserts and they NEVER leak.
Also, last thing.
I think you should only use "studs" coming out of the head for attaching the valve covers, never "bolts" going into the threaded holes. Also....the nuts you use are very important...you should use a nut with a "serrated" built in washer (one piece) on the nut. Those nuts "lock" down when they are tightened....dont use lock washers or lock nuts..only the nuts with a serrated base.
 
So the new steel vc have been ordered.Went the Home depot today and bought 1/4-20 x 3/4 inch stainless steel bolts from them with bonded sealing washers.I hope these will help seal the v c's. Ill check you guys updated.
 
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