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Discussion Starter #1
Is it possible to have the thickness of a cylinder head increased? I suspect the answer is no because I haven't seen it mentioned anywhere.

The head on my Guilia Sprint GT is below the minimum recommended thickness (between 110 and 111 mm) and I am getting a bit of pinging.

I use 95 octane fuel and I've retarded the ignition to the point where I'm having slight starting difficulties.

I gather that using thicker gaskets is not recommended, which only leaves having the pistons modified as far as I know.

Are there any other options?
 

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Is it possible to have the thickness of a cylinder head increased? I suspect the answer is no because I haven't seen it mentioned anywhere.

The head on my Guilia Sprint GT is below the minimum recommended thickness (between 110 and 111 mm) and I am getting a bit of pinging.

I use 95 octane fuel and I've retarded the ignition to the point where I'm having slight starting difficulties.

I gather that using thicker gaskets is not recommended, which only leaves having the pistons modified as far as I know.

Are there any other options?
You need to get or have made a Cylinder Head Shim.

The below link is just an example from a quick goggle search.

Innovative Machine & Supply

Dave
 

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Richard Jemison
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Head thickness

You dont need gimicks. The heads can be safly cut up to .070 less than original and if using standard (9,0 or 10.0 pistons, it shouldn`t ping with as much as .040 cut.
I suspect you have a distributor with the wrong advance curve for the engine build.
 

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Discussion Starter #4
Thanks guys,

Both of these suggestions are interesting.

A distributor with a different curve might get me out of my present difficulties and the shim option could come into play down the track
 

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You dont need gimicks. The heads can be safly cut up to .070 less than original and if using standard (9,0 or 10.0 pistons, it shouldn`t ping with as much as .040 cut.
I suspect you have a distributor with the wrong advance curve for the engine build.
Richard beat me to the same conclusion.
A quick check on the advance curve is to raise the engine RPM till the distributor stops advancing, then set the timing at the M mark (full advance). Then with the engine at idle see if the timing is retarded (to the right of the fixed pointer) or about 1/4 inch to the left of the fixed pointer. This will be about 5 degrees advance at idle which is close for a stock engine.
Also slowly raise the RPM and watch how quickly the timing advances. Full advance should arrive at about 3000 RPM.
Any thing different suggests that you should have the distributor advance checked on a test machine, or substitute one from a known good running engine.
Another thought is that a lean mixture could cause pinging, but there would be other complaints from you, such as popping back thru the carburators.
Hope this helps, George
 
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