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Username Post: Valve covers sealing        (Topic#368336)
IE 425 
Contributor
Posts: 216

Age: 52
Loc: Sacramento, CA
Reg: 06-22-07
05-04-22 08:57 AM - Post#2840690    

Hello Everyone,
I am trying to find the "secret" to getting valve covers to seal for a descent amount of time. I have tried the following:
Cork, dry (0 RTV)
Cork, very thin layer of RTV (both sides)
Cork, bead of RTV (both sides)
Rubber (Fel-pro), very thin layer of RTV
Rubber, bead of RTV

Changing out valve covers (maybe warped??)

BTW, the methods above have been on SB and BB...without success.

I don't expect the VC's not to ever start seeping but it is not long after I have tried the above methods that they start leaking again.

Any repeatable success with your methods? Any help is appreciated. As always, thank you in advance for your feedback.

-Paul


1965 Impala 327/300, 1965 Impala 396/425 L78 #'s Match. Keepin' it as original as possible!!


 


62sedan 
Very Senior Member
Posts: 4145
62sedan
Loc: Above the red Texas dirt
Reg: 08-12-02
05-04-22 02:48 PM - Post#2840705    
    In response to IE 425

Paul,

On the 327 that was in my Biscayne, I used the thicker version of cork gaskets (Fel-Pro I believe) and glued them to the valve covers with gasket sealer and let dry for 2-3 days before applying a very thin coating of motor oil to the cork. I never had any leakage and it made removing them no problem when having to adjust for solid lifters. And, the gaskets never stuck to the heads and could be reused as they were. Maybe it will work for you.

Chuck






 
redflags 
Contributor
Posts: 130

Loc: Palmerton Pa.
Reg: 07-21-12
05-04-22 03:09 PM - Post#2840706    
    In response to IE 425

I've had some that seeped and others that didn't using various brands and compositions. One thing I always do on steel valve covers is flatten the bolt holes before installing new gaskets, seems to help.



 
jktucker92 
Silver Supporting Member
Posts: 520
jktucker92
Loc: West Richland, WA
Reg: 02-05-17
05-04-22 08:07 PM - Post#2840714    
    In response to redflags

I agree with redflags. The valve covers should have washers that try to spread the load out and not deform the valve covers, but they still seem to press in where the bolts are. I've always used a ball peen hammer and not only flattened the holes, but actually dimpled them slightly away from the head. When tightened, the dimpled area invariably pushes in. Also, pay attention to the torque of them. I broke one off in my '66 when I was in high school and it was a pain getting the broken bolt out.



 
Tony1963 
Frequent Contributor
Posts: 1289

Loc: Orlando Florida
Reg: 07-09-18
05-05-22 03:51 AM - Post#2840720    
    In response to IE 425

Those steel valve covers can get twisted due to overtightening the bolts.

My suggestion is to take them out, clean off all of the old gasket and RTV, then sit them on a flat surface. Notice whether the edges are square to the flat surface or have any type of twist, bend or raised areas.

As mentioned, if the bolt holes are drawn down due to over tightening, use a socket on one side and tap them back flat.

Finally, agreeing that using those special washers to spread the load is a great idea. It keeps from bending the valve covers.

They are leaking because they are most likely not flat.

Also, agreeing with using RTV to attach the gasket to the valve cover but no RTV against the head.



 
bobb 
Super Senior Member
Posts: 6003

Loc: paradise
Reg: 09-05-03
05-07-22 09:47 AM - Post#2840828    
    In response to IE 425

you cant make the bolts too tight. you must use some type of load spreader. put some blue loctite on the bolts.

70 L camino, grampa engine, g-force 5 spd, road rage suspension. Pray first before all else fails.


 
Chevrobert 
Valued Contributor
Posts: 3880

Loc: Braintree, Ma. USA
Reg: 06-14-08
05-13-22 05:51 PM - Post#2841172    
    In response to 62sedan

  • 62sedan Said:
Paul,

On the 327 that was in my Biscayne, I used the thicker version of cork gaskets (Fel-Pro I believe) and glued them to the valve covers with gasket sealer and let dry for 2-3 days before applying a very thin coating of motor oil to the cork. I never had any leakage and it made removing them no problem when having to adjust for solid lifters. And, the gaskets never stuck to the heads and could be reused as they were. Maybe it will work for you.


I 100% agree.



Bob
'64 Impala SS
'77 Pontiac Ventura SJ
'83 Lincoln Towncar
Ain't to proud to think out loud.


 
Tony1963 
Frequent Contributor
Posts: 1289

Loc: Orlando Florida
Reg: 07-09-18
05-14-22 12:16 PM - Post#2841202    
    In response to bobb

I do not recommend any type of Loctite on the bolts. The gasket compresses over time and having the Loctite will interfere with the ability to tighten those bolts say 1/4 of a turn.

Those bolts do not typically loosen over time.



 
grechevy 
"5th Year" Silver Supporting Member
Posts: 173
grechevy
Age: 71
Loc: delaware
Reg: 01-25-09
05-15-22 07:18 AM - Post#2841220    
    In response to Chevrobert

i love the style of the old 327 factory covers tried every possible way to seal on my 65 impala.2 different sets,straightened bolt holes different gaskets sealers,no sealers spreader bars,still leaks.drug a pair of old finned corvette cast covers out of storage and installed,couple years no leaks.problem solved good luck.



 
Tony1963 
Frequent Contributor
Posts: 1289

Loc: Orlando Florida
Reg: 07-09-18
05-15-22 12:59 PM - Post#2841228    
    In response to grechevy

Those old steel valve covers probably were not flat, thus, the leak.



 


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