Problem Setting Dwell Angle

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Dec 20, 2015 | 01:45 PM

Griff2002

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From: Timnath, CO

Problem Setting Dwell Angle

My car was running well, but I decided it was time for annual check on dwell and timing. Was surprised to find dwell angle was about 20 degrees. I tried to set it back to spec of 28-32, but car would start to surge and I had to back off. Car runs very poorly now.

I changed the points to a new heavy duty set in case that was the problem (I did not change the condenser). Getting the same problem - have to leave the dwell in low 20's for the car to run, and it drives poorly.

A couple of other observations. I had the car professionally tuned a few years ago. I checked the dwell about nine months later and it was about 20 degrees (why?). I was able to adjust it to spec then and car ran well. Why did it change back to 20 degrees over the next year?

When I was poking around to get the allen wrench in the points adjuster I saw a spark. don't know if I briefly shorted something out.

When I drive the car now, It hesitates from a stop which it did not used to do. It also feels like it is hesitating while cruising at low speeds.

Any ideas on this?

Thanks

Dec 20, 2015 | 01:52 PM

toddalin

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From: Santa Ana CA

IIRC, it makes a difference in the reading if you set your meter on the pos or neg of the coil. Did you do it correctly?

Dec 20, 2015 | 01:52 PM

BBCorv70

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From: Tolland CT

Have you checked your timing since you adjusted the dwell?

Dec 20, 2015 | 02:10 PM

Griff2002

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From: Timnath, CO

Quote:

Originally Posted by toddalin

IIRC, it makes a difference in the reading if you set your meter on the pos or neg of the coil. Did you do it correctly?

Wow, I feel really stupid. Thought I remembered how to do this but I had it hooked up to the wrong side of the coil. When I hooked it up properly, the actual dwell was at 40 degrees.

I may feel stupid but relieved this was an easy fix. Thanks for your help.

Dec 20, 2015 | 02:11 PM

Griff2002

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From: Timnath, CO

Quote:

Originally Posted by BBCorv70

Have you checked your timing since you adjusted the dwell?

It was ~17 degrees initial but per my other response, I'll need to readjust it now that I've got the dwell corrected. Thanks

Dec 20, 2015 | 03:08 PM

toobroketoretire

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From: Great Plains Iowa

Quote:

Originally Posted by Griff2002

It was ~17 degrees initial but per my other response, I'll need to readjust it now that I've got the dwell corrected. Thanks

My old Marquette dwell meter has to be "zeroed" first to compensate for reduced battery voltage (uses a 9-volt battery). I suggest upgrading your ignition to a Pertronix to get rid of the points because points slowly destroy the upper shaft bushing because of the side load they impart on it. Or better yet go with an HEI.

Dec 20, 2015 | 04:33 PM

Griff2002

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From: Timnath, CO

Quote:

Originally Posted by toobroketoretire

When I was hooking it up incorrectly it was interesting that I got different results on my 35 year old Sear's dwell meter and the new timing light / dwell meter I got last year. Hopefully they will read the same hooked up correctly.

I only drive less than 1,000 miles a year so plan to stick with the points for now.

Dec 20, 2015 | 04:41 PM

427Hotrod

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From: Corsicana, Tx

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Yep...ck timing.

If you increase gap....you decrease the dwell....which increases the timing.

In your case...the rubbing block on points has worn...so you decreased the gap....increased the dwell...and decreased the timing.

Set dwell and then verify the timing.

A good set of points will last a long time. I used Accel's for years on the street with no issues at 7500 RPM and 800+ HP.

JIM