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Discussion Starter #1
Is it "okay enough" to use two head gaskets to raise head and relieve too much compression on probably twice shaved head already installed?
:)

Appreciate any comments about potential of this simple maybe easy fix.
Please don't be shy.
 

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Discussion Starter #3
:D
Good answer.

Had read elsewhere about using copper shims to do same thing.
 

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My Spider has a measured CR of 10.6 and it runs fine on premium gas with 34-36 degrees of advance. Are 9 to 1 pistons going to give you more than that?
 

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Yeah with these engines the head gasket already has a lot of work to do so I think this would be asking for trouble.

You could ...

Machine the block say 9mm's off the top (you would need to do some maths here to obtain the right number for your desired compression ratio). Get somebody to make a 10mm alloy plate that locates the top of the liners and has all the water and oil access, and head stud holes. Install that with a small amount of gasket sealant on the block side then install a single head gasket on top and slap on the head.

You would have to machine the 10mm alloy plate and timing chain cover once the alloy plate was installed to ensure the assembly is dead level. Of course you might need to make a plate that goes on top of the timing chain cover to get the top surface level ...

You will then have restored your compression ratio AND improved the locating of your piston liners :)
Pete
 

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Or buy a good, used head.
 
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Discussion Starter #7 (Edited)
Like your idea PSk...

Already have an apparently stock spare head in disassembly to make it ready for exchanging with current which sits on 10.4:1 pistons.
(hehe)
 
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