I read Pal Yaw's article on ignition timing and it seemed a little fuzzy for me. For my SE, he quotes timing settings at 24L and 16T at 4K. What I am wondering is, what do these settings mean for me at idle? What should the timing at idle that will put me in this range?

Mike

 

Depends on your year, but for 80's, timing at idle is 0 and 20. I believe some of the later ones change the trailing a few degrees.

The mechanical and vacuum advance mechanisms dymanically change your timing based on RPM and load.

 

the distributor has two mechanisms in it. it has vacuum advance, and mechanical advance.

briefly, setting the timing at 4000+ rpms, with the vacuum advance disconnected gives you the maximum mechanical advance, and this is what your timing will be at wide open throttle.

the distributors have different amounts of mechanical and vacuum advance, the charts are in the FSM, remember the dizzy spins at half speed, so you need to double mazda's number.

 

The entire point of this is to optimize the timing at higher rpms. Kinda like saying "to hell with my timing at idle". I have not tried this method myself yet, but if Yaw advises it then it must be okay.


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its not a bad idea to make sure the timing is right @ high rpm, especially with MSD or aftermarket efi....

i think on a GSL-SE, 24L @4000rpms = -3BTDC at idle, which is 2 degrees advanced, but its a bad idea to change timing without really checking.