Piston to head clearance??

[jimmymack87gn]

piston 0.010 out of the hole, will double stacking the stainless shim RJC head gaskets yield enough clearance??

 

[charlief1]

Assemble the engine without gaskets and put some caly on the top of the piston. Roll it over by hand and see what happens. If the valve contact the piston you shouldn't be able to rotate it that far and you can pull the head to see how far the valve needs to go down.

 

[bison]

It will be close but should be ok. The piston rocking will be the
determining factor. I've run .010 out with a .040 gasket and had it clear. I ran .013 out and I
could start to see a light shadow on the head. Tight=power and efficiency

 

[jimmymack87gn]

Assemble the engine without gaskets and put some caly on the top of the piston. Roll it over by hand and see what happens. If the valve contact the piston you shouldn't be able to rotate it that far and you can pull the head to see how far the valve needs to go down.

not asking about piston to valve clearance...

 

[jimmymack87gn]

It will be close but should be ok. The piston rocking will be the
determining factor. I've run .010 out with a .040 gasket and had it clear. I ran .013 out and I
could start to see a light shadow on the head. Tight=power and efficiency

Thanks!!!

 

[Buickrat]

I would run a .050 head gasket with cast or steel rods, that will give you a .040 quench height. .040 with pistons out of the hole is to tight.

 

[turbofabricator]

Order Cometics in the thickness you need.

 

[jimmymack87gn]

Order Cometics in the thickness you need.

engine in my car has cometics & have leaked since day 1, building this one for a friend

 

[jimmymack87gn]

I guess what I mean to ask if anyone knows what the compressed thickness of 2 rjc stailess gaskets are???

 

[turbofabricator]

I spray copper coat on each layer of a Cometic and never have an issue with leakage. I've cracked a cylinder wall and the gasket is still in GREAT shape. To answer your question, though, stacking gaskets is going to double the thickness. If they are .020" then two will equal .040". Maybe slightly more depending on sealer used. Your deck and head surface MUST be smooth when using steel gaskets either MLS or single layer steel ones. Factory machined block and heads will not properly seal with a steel shim type gaket. The RHR finish of the factory machining creates small channels for fluid and compression to leak from.

 

[pacecarta]

stock gm were .017 ea . rjc uses 2 stacked per side so .033 , stacking two sets (4 shims) .066 ..same as a GM composition stock gaskets but more expensive , you can get cometics in various heights , .040/.050/ .060

from rjc site the gasket he has is .033 compressed
http://www.rjcracing.com/product/head-gasket/

 

[bison]

Check the compressed thickness with a feeler gauge after install. I've found stacking gaskets doesn't add up like it should. Usually results in more thickness than anticipated.

 

[jimmymack87gn]

Check the compressed thickness with a feeler gauge after install. I've found stacking gaskets doesn't add up like it should. Usually results in more thickness than anticipated.

Don't know why i didn't think of this, am going to try it this week. I greatly appreciate all the input.