I am planning to get underdrive pulleys sometime, mostly because I do high RPMs a lot. But I don't want dim headlights for normal driving and whatever else happens when no power goes to the electrical system.

So just wanted to know how well they work with various member's setups. Is it simple and straight forward to replace the main pulley? I don't know how the timing crap works. And do you notice the amount of power they free up?

Yup thats a lot of questions.

 

I never found the Main pulley replacement to make much difference in power. The main reason to change it out is for the timing marks if you disconnect vacuumm advance and need to advance timing marks.
Also there is a huge risk that you can damage you the seal/bearing on the eccentric shaft if you don't follow specific instruction.
You can get more benefits by upgrading a pre'84 Rx-7 to a '84-85 unit, which does not use a exteral cooling fan.
The biggest bang for the buck is of course is installing a electric fan.

 

The design of the pulley is to reduce the revs of the alternator so it will not burn out the bearings at the high rpm of race engines.

If you use the car at low revs the charge made by the alternator is smaller. Thus the battery may go flat in typical street use due to the drain being higher than input. Remember the race cars require less electicity.

What will make the lights dim is a battery which is flat, the long term electrical use is not being met by the slow turning alternator.

 

Hey,

I have done RX7Carl's Rats Nest Removal, and I cannot get the leading and trailing timing marks to appear. I even went so far as to remove and reinstall the pulley 180 degrees, and it still has the same problem.

Does the Rats nest removal change the timing marks?>

HELP

 

did you hook up your timing advance vaccum lines

 

did you hook up your timing advance vaccum lines

 

did you hook up your timing advance vaccum lines

 

did you hook up your timing advance vaccum lines

 

Yes, I believe so.

Those are the ones that are connected to the dizzy, right?

 

You can say that again .

~T.J.