Re: A pop quiz on some engine tests

[Mark Pollan <Mark.POLLAN@mci.com>]

>Now the question: how come that after doing the head work and lapping
>the valves the compression figures have dropped while the leak down test
>shows a great improvement, meaning that the valves are lapped very well
>and that the rings seal very tight? Why is such contradiction? A damn
>mystery!

I'll take a shot.  Non-uniform carbon deposits causing non-uniform
albeit higher compression.

Mark Pollan, '86 5KCSTQ 250K Miles