One of my friends back in the USAF learned the compression lesson the hard way. He bought a set of custom-made 11:1 compression pistons for his Morgan Plus 4 sports car which ran the same engine as a Triumph TR-4. When I suggested he should also step up to a longer-duration cam, he told me he didn't like the lumpy idle. We ended up setting the static ignition timing a few degrees AFTER top dead center to avoid severe detonation on acceleration! Now, the Triumph engine was a "wet sleeve" design- - - - -the coolant is right against the back side of the replaceable cylinder sleeves. Within a month, he had cracked three sleeves top to bottom from detonation. The third time we tore the engine down, he decided to go back to running stock-compression pistons. High compression MUST be used with a radical cam grind, but it's destructive to an engine with a standard cam.
Jerry
