Valve cover gaskets

[Mopar Mitch]

Rubber gaskets (die-cut neoprene, molded silicone) are always best installed dry... molded silicone MUST be installed DRY... any wet supplemental chemical will ONLY act as a "lubricant" that welcomes the gasket, upon being squeezed/compressed, to slide out of position, unless and only unless, it is additionally mechanically clinched into a fixed position.  Fiber or cork-rubber gaskets are best installed, again as well, DRY.   The gasket does the sealing.. NOT the chemical.  Do you see the common outside gasket tabs?.. they fit into the cut openings of the valve cover to mechanically clinch it into a fixed position... NO chemical needed.   Remember this: rubber is NOT compressable.. it distorts upon being squeezed and WILL SPLIT apart if squeezed too much.. typiocally rubber is best only squeezed to approx 30% maximum of its static thickness;  cork-rubber can be "compressed" up to 50% maximum before distortion and splittong can occur.   BEST BET -- ALWAYS INSTALL THESE GASKETS (DIE-CUT NEOPRENE RUBBER, MOLDED SILICONE OR CORK-RUBBER).. DRY WITHOUT ANY CHEMICALS.

[cudabob496]

Rubber gaskets (die-cut neoprene, molded silicone) are always best installed dry... molded silicone MUST be installed DRY... any wet supplemental chemical will ONLY act as a "lubricant" that welcomes the gasket, upon being squeezed/compressed, to slide out of position, unless and only unless, it is additionally mechanically clinched into a fixed position.  Fiber or cork-rubber gaskets are best installed, again as well, DRY.   The gasket does the sealing.. NOT the chemical.  Do you see the common outside gasket tabs?.. they fit into the cut openings of the valve cover to mechanically clinch it into a fixed position... NO chemical needed.   Remember this: rubber is NOT compressable.. it distorts upon being squeezed and WILL SPLIT apart if squeezed too much.. typiocally rubber is best only squeezed to approx 30% maximum of its static thickness;  cork-rubber can be "compressed" up to 50% maximum before distortion and splittong can occur.   BEST BET -- ALWAYS INSTALL THESE GASKETS (DIE-CUT NEOPRENE RUBBER, MOLDED SILICONE OR CORK-RUBBER).. DRY WITHOUT ANY CHEMICALS.

Makes sense, but the form-a-gasket, once applied to my cork gasket, is allowed to partially dry, before you torque the valve cover bolts.  What is your opinion on using this? It finally stopped a leak that the cork gasket alone could not.

[dodj]

You should consider the Fel-Pro VS50145R valve cover gasket set.  These are constructed of a rubber-coated high-temperature fiber and are designed specifically for the 6-bolt BB heads, in particular for extreme heat applications such as trucks and emergency vehicles.  The same gaskets are packaged in the Fel-Pro Performance Set #1612. 

Are they reusable?

[Mopar Mitch]

Using the "Form-A-Gasket" type of selaer and allowing it to partially dry...  better to allow it to completely dry, because, as it would still be "wet", it could act as a lubricant and allow the gasket to slip out of position.  Gasket instructions within the manufacturer's package will typically refer to use a "quick-drying contact adhesive/cement" for cork-rubber gaskets, or else the hi-temp rubber-coated fiber gaskets.... and rubber gaskets are best installed dry.  The critical point is to be certain whatever chemical used (IF used.. I never use any because I have flat flanges of the cover and head!), is that the chemical will be completely dried to the gasket BEFORE squeezing the gasket.  So, could someone safely/slightly squeeze the gasket now... and then later, say 20-60 minutes, fully tighten the gasket (with proper torque and cleaned threadings)?  It will likely work, BUT.. be careful with the RTV/silicones... they ALL require lengthy time (60 minutes minimum, 12 hours is best, pending humidity in the ar (RTV requires humidity to fully cure)).  PLUS... you don't want to let ANY RTV get inside the engine.. easily clogs various oil passages, oil pump screens, etc!!!


Can the Fel-Pro hi-temp gaskets (VS-50145R and related) be re-used?   Technically, no gasket should be reused because of the compressed state it will have taken... and IF re-used it would have to be re-installed in the same exact location using the same exact castings, etc.   However, you be the judge... I've re-used the valve cover gaskets for a few times (R/R the cover for valve train inspection and adjustments, etc), but eventually I'll replace the gaskets.... and having NO chemical adhering the gaskets is a huge plus since the gasket tabs fit securily into the valve covers (most covers will have the cut open side tabs for the gasket).   

For any die-cut rubber or molded rubber gaskets, always look over them carefully to assure that the gaskets haven't split at any area (due to over squeezing).  IF any splits are visible, be certain to replace the gasket.  Also, re-inspect the gasket mating surfaces (cover and head) as there may be signs of out-of-flatness that would contribute to the excessive gasket squeezing.

Another "tip" is to use wide/long load-spreading washers at each cap screw or stud ... this spreads the clamping force widely instead of within a narrow area.

[cudabob496]

good tip on the washers!

[dodj]

Thanks Mitch 

[Mopar Mitch]

When I worked for Fel-Pro as an Application Engineer throughout the 80s-90s, I gave hundreds of gasket seminars around the country.

[cudabob496]

http://www.summitracing.com/parts/dcc-4349620/overview/

[cv70chall]

I've read your entries and yes, I've been having the same issues. I've tried cork and the Moroso rubber/ steel core gaskets with no luck. I've had the Mopar Perf. Aluminum covers and now Chrome covers.
--- Passenger side still leaks- from the two lower areas where the oil pools during running.
I've sealed the gaskets to the inside of the valve cover with Permatex Ultra Grey and even the Ultra Black- and let the assemblies sit for over a day before installing- and still leaks. I'm sure this is leaking at the top of the head where it meets the valve cover- most likely.
I've heard because the stock head rails are uneven and sometimes porous- that applying a primer (Rustoleum 769 or Indian Head) works well to even out and seal the tops of the heads.
Is this true? If so, I would like to try Indian Head along the sides and bottom of the head rails.

I just want this to stop. I've now got steel/ chrome valve covers and a set of new Mr. Gasket Ultra Seal gaskets that I want to install this next- and hopefully LAST time.

[cudabob496]

I used the Moroso's, and had some leakage, so I went back, cleaned things up,
then used that black high tack stuff on the valve cover, before putting on the Morosos.
Then let it dry a day, while at the same time making sure the Morosos were properly positioned.
Then put valve covers on engine, and torqued the bolt not too tightly.
No leaks now. But you can't torque the Morosos down too much, or they can squeeze out
of position.

[tman]

Something about the passenger side likes to leak on the big blocks.  The HP manifold is so close, that it gets very hot there.  That is where my leaks occur.  Every other year, I have to change the passenger side.  The driver side, I have not had to re-do for many years.  I have the stamped steel valve covers.  A member used the Superperformance CarbonX with success.  Anyone else use them?

http://www.manciniracing.com/sucavacoset.html

[cudabob496]

I think in most cases the valve cover is not perfectly flat, or its flimsy,
or its not thick enough for the 6 bolts to provide adequate clamping force.

[Topcat]

I haven't seen anyone here mentioning about truing the valve cover sealing area.

New or used, I would think it's a good idea to go over the valve covers with a fine tooth comb (so to speak)
on any imperfections of highs/lows/unequal areas.

Even cast aluminum covers should be double checked as well.   

[Mopar Mitch]

Flatness and clamp load are the critical issues.  Many long years ago, Fel-Pro developed a hi-temp v/c gasket intended for trucks, emergency vehicles (ambulances, police cars, etc). etc... all those engines having the close raised cast iron mflds... VS-50145-R (I think is the set number) ... they have it for the LA s/b and the bb applications... proven (I was personally involved)... but again.. flatness and clamp load are critical.... stamped steel covers tend to easily distort when excessively clamped.  Adding chemical (adhesives, etc) does NOT help seal the gasket ... the chemical only holds it in position during installation.. the gasket does the sealing, not the chemical.

[cudabob496]

Flatness and clamp load are the critical issues.  Many long years ago, Fel-Pro developed a hi-temp v/c gasket intended for trucks, emergency vehicles (ambulances, police cars, etc). etc... all those engines having the close raised cast iron mflds... VS-50145-R (I think is the set number) ... they have it for the LA s/b and the bb applications... proven (I was personally involved)... but again.. flatness and clamp load are critical.... stamped steel covers tend to easily distort when excessively clamped.  Adding chemical (adhesives, etc) does NOT help seal the gasket ... the chemical only holds it in position during installation.. the gasket does the sealing, not the chemical.

yes, the high tack holds it in place. Its easy for the gasket to move on its own, to slip out of place, especially when the Morosos do not have those tabs that
stick out for positioning.