RickKlem

My car has a Bosch distributor, and I'm trying to set the timing. The problem is the distributor is turned all the way clockwise ( bottomed out) but I'm still about half an inch or so to the left of tdc or Z1 mark. I'm sorry I'm new to setting up the timing, done it twice on a Chevy, but I guess that would be BTDC.

This is a stock engine , so I guess I'm right by saying it should be set at 0% or the Z1 mark. They are the same marks , right? Why is it bottomed out but I'm not there yet? How do I fix my problem. It idles around 950rpm's once warm.

Thanks
Rick
1977 911 s

Bill Verburg

You may be a tooth(or more) off. Unlike many distributors the point type distributors can be installed in as many ways as there are teeth on the drive gears. If the timing light shows that you are to the left of the Z mark at idle speeds that means your timing is too far advanced(~1 degree/mm), If the distributor is all the way clockwise, Pull the distributor rotate the shaft 1 tooth clock wise, try it again.

There is an official procedure for getting the #1 cyl. to TDC on the intake stroke but its often ignored. Just keep in mind that the rotor should be pointing to the #1 sparkplug wire when the #1 cyl is at ~TDC on the intake stroke(both valves on #1 closed). Don't forget that Z1(TDC) occurs twice, once on the intake and once on the exhaust stroke(the rotor should point to #4 sparkplug wire at Z1 on the exhaust stroke, both #1 valves open)

Howard

Bill,

If the timing light shows the timing to be left of the Z1 mark wouldn't that be "retarded"? the light should show the proper timing at idle to be at 5 degrees BTDC which would be CW of the Z1 mark. And at 5000 rpm should show approximately 26 degrees BTDC or CW of the Z1 mark.
Rick, carefully lift the distributor and rotate it CCW one tooth, then re-seat it with the rotor pointing at cylinder number 1 at TDC, that should get you close.
Good luck !

Clark Griswald

Follow the above advice on re-indexing and set up the timing at idle.

Then check the operation of your advance mechanisms. You may have a seized distributer. That may be why you can't bring it into adjustment.

RickKlem

Thanks

I thought you could do that , I just wanted make sure.

I will try it tonight , and then post my results.

Thanks
Rick

Bill Verburg

I stand corrected, for some reason I remembered 5ATDC on the other side of TDC, Early onset of oldtimers I guess, now where did my glasses go.... <img src="graemlins/c.gif" border="0" alt="[ouch]" />

RickKlem

Update!

I moved the shaft ccw one tooth, then moved the dist. ccw all the way . Now the Z1 mark on the pulley is about half inch to the right of the mark on the housing. That is the only way to keep the car running. If I move the dist cw it moves the Z1 mark even further away to the right of the mark and the car stalls.

So I moved the shaft back to the orignal placement moved the dist cw all the way and i'm back to where I began. With the mark to the left of the mark on the housing.

Yes, I only moved the shaft 1 (ONE) tooth, Trust me, I did it four times, with the same outcome!

Is there anything else I can try? The car runs fine like this but I want it to be correct.

Thanks
Rick

Howard

Rick,

I just checked the book on timing for your application. The timing at idle should be at Z1 0-2 degrees BTDC.(to the right of the mark,cw) if you still have a problem then it must be the injection or carbs. We need more info !
Let us know..