Dwell to set points

[Doug&Deb]

When using a dwell meter to set points how does the dwell angle correspond to the points gap? For example I think my dwell angle is 38 degrees. If it’s 30 do I increase or decrease the gap? I’ve always used a feeler gauge but I’m always willing to learn a better way.

[Sniper]

Dwell is the amount of time, expressed in degrees, that the points are closed.  Increasing the gap decreases the dwell.  Unfortunately, I do not have a rule of thumb that correlates gap to dwell time.

[busycoupe]

I also do not have a rule for correlating point gap with dwell angle, but I think that it would depend on the shape of the distributer  cam.  

[keithb7]

Best bet is to seek out a used old dwell meter on your local on-line classifieds. Perhaps a swap meet some day in the distant future when they can have them again. They are cheap, (majority of people have no clue how to use one anymore) and in low demand. A great tool to have to keep your old Mopar well tuned up! I'm am quite pleased with my old 70's dwell meter.

[desoto1939]

1 hour ago, Sniper said:

Dwell is the amount of time, expressed in degrees, that the points are closed.  Increasing the gap decreases the dwell.  Unfortunately, I do not have a rule of thumb that correlates gap to dwell time.

Sniper: So here is how I understand what you are saying.  If the correct gap is 20 and if we assume you can get a perfect 20 gap then the dwell meter on my 39 Desoto would read 38 onthe dwell meter.  But if I gap the points at 18 this would mean that the points are closing sooner and then the dwell metter should read higher than the 38 possibley 40+.  So if you undergap the point then the dwell will be higher and if you over gap the dwell will be lower.

 

This is how I understand the dwell number with a dwell meter.

 

Rich HArtung

desoto1939@aol.com 

[greg g]

Think of it like theater seats.  Points gap gets you to the row, dwell puts your fanny in the right chair.

[Sharps40]

To answer your question directly.   Large gap equals small dwell.  

 

To set points ignore the points gap/feeler gauge method.   Set dwell to lower limit.....(large gap) and the tune will last the longest as the gap closes up and dwell increases with miles driven.

[Sniper]

10 hours ago, desoto1939 said:

Sniper: So here is how I understand what you are saying.  If the correct gap is 20 and if we assume you can get a perfect 20 gap then the dwell meter on my 39 Desoto would read 38 onthe dwell meter.  But if I gap the points at 18 this would mean that the points are closing sooner and then the dwell metter should read higher than the 38 possibley 40+.  So if you undergap the point then the dwell will be higher and if you over gap the dwell will be lower.

 

This is how I understand the dwell number with a dwell meter.

 

Rich HArtung

desoto1939@aol.com 

 

If by undergap you mean a smaller gap and by overgap you mean a larger gap, then yes.

[DJK]

I "eyeballed" my point gap and timing one time after a break down on the road, car ran but wasn't happy. With dwell set at 38 degrees and timing at 6 degrees, runs great. I attempted to set dwell while cranking engine, more accurate if dwell is read while engine is running.