yet another gap/dwell question.

[robmog]

1972 911 E MFI fresh rebuild.
I set the gap with distributor out, exactly .014" as spec.
the dwell is < 25.
i know to increase dwell you must decrease gap.
how low can i go with gap setting?
or is that dwell so far off my dwell meter is not correct?
thanks

[Paulporsche]

Well, it could be a number of things, but If you are sure your feeler gauge is correct, and you are correctly located on the cam of the distributor shaft, then I would suspect the dwell meter is incorrect. If your shaft or the points were worn or if you were not on the high point of the shaft you would get a higher than spec dwell number. You would get a lower number if the feeler was too thick.

Are you able to zero it before attaching to the distributor?

Are you able to check the dwell on some other vehicle?

You should only be 3 degrees +/- of your spec, which is 37 or 38 depending on what type of diz you have.

[robmog]

Thanks Paul, that info is what i needed. I suspect the meter is off. I'll try a different one.

[Driver_X]

Make sure you meter is set for 6 cyl & not 8 or 4.

[robmog]

It was, but thanks for the input. Sometimes it's the little things that get you.

[Eagledriver]

I don't think the dwell is important in this application. The points only act as a switch for the CDI. The dwell is not used to charge a coil like early non CDI systems.

-Andy

[robmog]

My OCD makes me want it to be right LOL.

[Driver_X]

Yeah, I'm kinda of an expert in that area

[Peter Zimmermann]

The point "gap" is only considered a rough setting to get the car started. The "dwell angle" is the accuracy component of a tune-up; the adjustment that takes away possibility for errors that can be made using a feeler gauge.

[Paulporsche]

Andy is right in that the gap isn't as important on CDI cars in that it doesn't affect the timing. I'd be concerned, though, if it were too out of spec that the thing may not be firing as well as it should.

In your case you may be just fine if it turns out it's just the meter.

How does the engine run?

[robmog]

It was the dwell meter.
Got a new one and it was perfect at 38 degrees.
Thanks all.

[Paulporsche]

Sounds good!

Just a thought--if you start out @ 38 you will eventually get to the wear limit of 41 of course, as the nub on the points wears down. If you are diligent you can adjust the points periodically and keep them @ or near 38. If you are lazy like me, you can start out @ 35, let them gradually go to 41 and then replace them. I have to admit, though, I've never gone back and reset them after they've gone to 41, so I don't know if there is enough meat left there to get back to 38.

[robmog]

I think I'm gonna enjoy it for awhile!