I read a lot of guys have problems with the rubber gaskets and ditch them in favor of RTV. Then I read a lot of guys tried RTV, even The Right stuff, and also had problems. Damn shame those china wall rubber gaskets are available and claimed not to work.

Anyone ever had success with these rubber gaskets?

 

Headgasket thickness variations and cylinder head resurfacing, block decking, etc ensure that the silly rubber gaskets are NEVER the correct thickness. They are either too thin to seal, or too thick and they squeeze out.

GD

 

Nice explanation of why they fail. I just happened to be on Fel-pro site reading Fel-pro recommendations, they stand behind their china wall seals as long as none of what you said has been done. Another thing I'm running across is a lot of guys use RTV on Felpros, Felpro's says dont do that. it will change the chemistry of their seals, and cause them to fail - only put the sealant where the china wall gasket meets the intake.

 

I Used GM Gasket Kit 10147994 20 Years Ago,Never Had Any Problems.

 

If you use a bead of the right RTV you don't need the rubber china wall gaskets. We prefer the ThreeBond 1271H. You can get this in mini caulk tubes from the Nissan dealers for about $16. It's has a higher initial viscosity than other RTV products and lends itself really well to areas like this SBC china wall.

GD

 

The Right Stuff is my sealant of choice. RTV can shrink and leak when it cures and doesn't always stick to partially oily metal.

 

Like GM? Cleaned up a take off ZZ4 intake a couple years ago. It was sealed with gray RTV.

 

Taken at a large car show here in Michigan in 2017, at a GM dealers tent selling GM Performance parts and crate engines. I just wanted to document for myself, for when I go through my SBC, that this is the way GM Powertrain is sealing these intakes, complete with a little of the grey stuff about one third of the way up the head on either side of the intake gasket. They have to warranty the thing, so if it's good enough for the General, it's good enough for me.

 

I can tell you from personal experience, that crap does NOT come off easily. It took some work to get that intake clean. A fresh razor blade barely touched it. Knowing GMPP just a little, I'd bet that stuff comes out of a Permatex Ultra Gray marked tube, or a tube that looks suspiciously like the Permatex tube, but with a GM logo printed on the side.

 

Thanks for feedback guys. Decided not to use the rubber gaskets, turned out nice. It probably is very difficult use rubber gaskets while engine in car. out of car may be a different story.