Setting timing with high compression

[dseretakis]

I'd like to adjust the timing on my 71 280SL but my compression is 200psi.  I read in an old post that it is a pointless exercise to use a timing light in this case and that one must just set timing by ear.  Is this the case?

[hill]

I'd like to adjust the timing on my 71 280SL but my compression is 200psi.  I read in an old post that it is a pointless exercise to use a timing light in this case and that one must just set timing by ear.  Is this the case?

Try another compression gauge.  200 psi would be 12/1-13/1 compression ratio?

[ja17]

Hello,

Yes try another gauge.  However, I have seen heads over milled so much that the compression is this high. If so, use the highest octane gasoline you can find and turn the timing up as far as possible until some engine "pinging" is noticed (engine hot and under load) then turn it back just enoough, so absolutely no "pinging" can be noticed.

[dseretakis]

Yes, I will try another gauge, but in the meantime my car has started to re-exhibit the same problems as prior to replacing fuel pump.  It will start (hard start) but then not really idle.