timing for an 81 sc engine at 6000?

[mb911]

Just as the title says what is the correct timing?? I forgot> I knew it a year ago and did a search but can't find anything now.. Anybody??

[mb911]

35 degrees ay 6000?? rings a bell

[emcon5]

SC timing specs per the Bentley manual are:

78-79, 5º ±2º BTDC@ 950 RPM, vacuum hose connected, with max advance 26º ±2º BTDC @6000rpm, vacuum hose disconnected

80-83. 5º ±2º BTDC@ 950 RPM, vacuum hose disconnected, with max advance 21º ±2º BTDC @6000rpm, vacuum hose disconnected

For best performance, John Walker (and others) advocate leaving everything hooked up and setting it so full advance is 35º, and not worry about the timing at idle.

Tom

[Vipergrün]

I thought the best was to disconnect the O2 sensor (if you have one) and richen the fuel mixture?? Be sure to back of the advance if you have ANY signs of detonation.

-B

[Superman]

Yes, many of us prefer to disconnect our O2 sensors. No need to lean out the mixture as much as the computer does, except for emissions reasons.

JW does like to time all these cars at 35 degrees BTDC at maximum advance (probably 5000 rpm is maxed out anyway), with everything hooked up. These engines are noisy so you have to listen for detonation. But you can hear it. It's not inaudible as some would suggest. You can hear it. And if you do, back off the timing.