Message text written by Graham McMicken
>I have a 1975 TR6, This winter I will be doing a couple of things to it,
including adding overdrive, tuning carbs (correctly), rings, valves, and
I need some advice on Raising the Compression Ratio. It is currently
at 7.5 (? 7.75 ?) and I want to know what I need to do to raise it, the
benifits, and if its worth while.
<
Graham, buy Kas Kastner's special tuning manual and show it to your
machinist. If you are pulling the head anyway, take your head to a machine
shop and have the valve guides replaced and the head shaved. Kas' manual
will also include some other minor details you can do to improve things.
It all depends on how much you want to spend.
I took an early head to a local head porting expert and he shaved .060 off
and replaced the valve guides and springs and it cost me $350 (US). He
also radiused the sharp edges in the combustion chamber to reduce pinging.
I figure I have about 9.5:1 (or so) compression ratio and It runs fine on
89 octane gas.
But start with the Kastner manual.
Cheers
Dave
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