Thicker Head gasket/Push rod length

I had to lower the compression on an engine I have and bought some .080 Cometic Gaskets. I am feeling I might have to get longer pushrods becuase this can throw the geometry off I have heard. ANy idea what increasing the thickness .040 will require?
I am going to try to get the heads bolted on Sunday.


Thanks Tore

Fit up and look at what you got, it may be acceptable as is.

dfree383 wrote:Fit up and look at what you got, it may be acceptable as is.

x2 .040 isnt much

I kind of wondered if I would be lucky and they would work. Just wanted a couple opinions.


Thanks Tore

Tore wrote:I had to lower the compression on an engine I have and bought some .080 Cometic Gaskets. I am feeling I might have to get longer pushrods becuase this can throw the geometry off I have heard. ANy idea what increasing the thickness .040 will require? I am going to try to get the heads bolted on Sunday. Thanks Tore

I just did a check on the engine I am building and changing the push rod length .050" moved the pattern on the valve tip from slightly off center on the intake side to slightly off center on the exhaust side. I do not know how this would equate to increasing the gasket thickness, but when changing the push rod the result is magnified by the rocker ratio. So I would not think you would get that much of a change with the gasket thickness.

Will be interesting to find the answer,because you are raising the head up .040 extra . Gonna kill the quench,but it's mainly a street engine so can't be too bad.

dfree383 wrote:Fit up and look at what you got, it may be acceptable as is.

As Dave has replied, do your homework! Pushrod length usually is offered in .050" increments. You just never know unless you check. The rocker tip/valve tip relation could be a bit off, changing the effective height of the cylinder head in relation to the block could make it better or worse. With light valve springs, component wear may not be accelerated as with stiffer springs. Although we always seek perfection, in the area we discuss, one may get by with a bit less perfection!

Dave.

shaft rockers takes the worry out of being close

Larry Williams wrote:shaft rockers takes the worry out of being close

As the head gasket gets thicker it will require running the adjuster out of the rockerarm more...at some point it'll make the rockerarm more prone to breakage. There is no free lunch with either style rockerarm.