If points gap is correct, should dwell also be?

[jwakil]

I'm trying to adjust my distributor with points. If I get the gap correct, does that imply that the dwell angle should be fine? I'm trying to decide if I need a separate dwell meter.

[HarryD]

If you get the gap correct, the dwell "should" be within range. The dwell meter will serve to fine tune the setting.

[Superman]

Harry is correct. However, no matter how close you think the gap is, the dwell angle will almost certainly be incorrect. A dwell meter will tell you how close you got it when you set the point gap. Also.....dwell meters can be had for peanuts. Thrift stores, pawn shops, garage sales, etc. Better yet, do yourself a big favor and upgrade to an electronic ignition trigger.

[Bill Verburg]

Originally Posted by jwakil

I'm trying to adjust my distributor with points. If I get the gap correct, does that imply that the dwell angle should be fine? I'm trying to decide if I need a separate dwell meter.

point gap determines dwell, the wider the gap the lower the dwell.

The more precise measure is dwell.

Set the gap w/ feelers then zero it in w/ dwell.

since the primary issue w/ points as implemented in a Porsche CDI system is rubbing block wear and the resulting decrease in point gap over time, it's best to set up the gap on the high side, which is on the low side for a dwell measurement

[911pcars]

Originally Posted by Bill Verburg

point gap determines dwell, the wider the gap the lower the dwell.

The more precise measure is dwell.

Set the gap w/ feelers then zero it in w/ dwell.

since the primary issue w/ points as implemented in a Porsche CDI system is rubbing block wear and the resulting decrease in point gap over time, it's best to set up the gap on the high side, which is on the low side for a dwell measurement

To add to Bill's response: Every 1 degree of dwell change also changes the ignition timing by the same amount. Thus, as the rubbing block wears, the point gap becomes smaller and the ignition retards (e.g. 5ºBTDC > 4ºBTDC).

Sherwood

[rattlsnak]

yes, and dwell affects timing, but timing does not affect dwell...

[dan88911]

Originally Posted by Superman

Harry is correct. However, no matter how close you think the gap is, the dwell angle will almost certainly be incorrect. A dwell meter will tell you how close you got it when you set the point gap. Also.....dwell meters can be had for peanuts. Thrift stores, pawn shops, garage sales, etc. Better yet, do yourself a big favor and upgrade to an electronic ignition trigger.

Don't mean to high jack. However, what is this electronic ignition trigger you speak of ?

[HarryD]

Originally Posted by dan88911

Don't mean to high jack. However, what is this electronic ignition trigger you speak of ?

Good question. I presume we mean someting like Pertronix (Pelican Parts.com - Pertronix Ignitor) or other electrical item to replace the points with an electronic triggering device.

[dan88911]

Thanks HarryD. I remember something like this in the 70's for muscle cars.

[Joe Bob]

Pertronix while a good idea, are failure prone, hence the recommendation to carry points with you on the road.....