20lbft torque is good, and yes it should be done cold. Did you follow the recommended head nut tightening sequence Bob?
Did it run at first then stop, or hasn't run at all?
Is there water in the bores?
Is the head warped? (alloy heads especially are prone) - may be worth laying it on a surface plate to check.
As Alan said, anything stopping the valves closing properly?
Have you used a HC head gasket? (I can't immediately think what would happen; but HC and LC gaskets are different shapes).
Changing your compression ratio theoretically could put your ignition timing out a bit, but I'd still expect it to fire.
Have you altered anything else?
Did it run at first then stop, or hasn't run at all?
Is there water in the bores?
Is the head warped? (alloy heads especially are prone) - may be worth laying it on a surface plate to check.
As Alan said, anything stopping the valves closing properly?
Have you used a HC head gasket? (I can't immediately think what would happen; but HC and LC gaskets are different shapes).
Changing your compression ratio theoretically could put your ignition timing out a bit, but I'd still expect it to fire.
Have you altered anything else?