'71 250C Timing

[SatRoc]

Could someone tell me what the OPTIMAL timing should be set at at both idle and 1500RPM? Haynes says 4 degrees ATDC @ 1500. I know this is for smog control, but I would be interested in optimal, for testing purposes only of course. Thanks in advance!

[t walgamuth]

at high rpm. so check your specs. and see what advance is built in to your distributor. there will be mechanical acvance and vacuum advance. total these up and subtract from 36 what is left is what you want to start with, so say you have 20 degrees mechanical advance and 10 degrees vacuum that is 30 total so you want to start with 6 degrees btdc at idle.

so check inside your distributor to see that your mechanical advance is in good shape. the weights and springs can break. also they can stick so a cleaning and oiling might be in order. then check your vac advance to be sure it is working. you can suck on it and watch it retract. if it leaks replace it.

good luck. if you need specs let me know. i have old books with them.

tom w

[SatRoc]

Thanks Tom! I'll give it a try tomorrow.