On 12 Oct 1997, Joe Curry wrote:
> I am not sure what the compression should be in your particular engine,
> but 180 psi does not sound incredibly high. If you are running regular
> gasoline, you might try upgrading to premium or trying an octane
> booster to see it the "pinging" subsides.
I can only second that. Use the highest octane rating consistent with
removing pinging and detonation completely. One might even have to add
toluene to the gasoline to increase the octane rating.
Don't ignore pinging. If the engine pings at high RPM and high power
output (almost impossible to hear) it will quickly crush the compression
rings and destroy pistons.
The squish area, present in engines with "bath tub" heads like the
Triumph, creates special problems re. detonation. For anyone planning to
increase the compression, the #1 thing to do is to decrease the height of
the squish area. In practice, this can be done by removing material from
the top of the block. Enough material for the pistons to appear flush with
the block at TDC, ideally protruding a little (but not so much that the
pistons will actually hit the top when hot, of course).
Egil
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