Quick question about dwell on my dual point distributor. First off the motor (hemi) fires right up and runs great. I changed plugs last night and opened up the distributor to check gap/condition of my points. One was at .016" and the other was about .013" so I set them both to be at .016" (FSM calls for .014"-.019")Point contacts look good. Afterwards when I checked the dwell with a meter it read 35.5, FSM calls for 37-42 when checking both. I did not check each set individual. Before I start changing things around is my .016" gap reasonable for the dwell? Do I need to open up the gap to optain the dwell numbers per the FSM or is what I have acceptable?

Jim

it's the dwell time that affects the points, longer dwell gives more coil saturation/but lower point life from more time that the current is passing thru them. less dwell gives less saturation/but longer point life. more gap gives less dwell. There's alot of leeway there for experimentation and I'd say you're good. Ma upped the gap so as to lower the dwell time so the points would last a reasonable amt of time. For max power (& shorter point life) you can decrease the point gap (more dwell). bottom line is how often are you willing to change points. Also a large gap MAY contribute to point bounce at higher rpms and point spring tension is a factor also

Thanks for the response. I've had this motor to 6K plenty of times already and never an issue with ignition so far. Sounds like the .016" is a good measurement to keep, seeing that it falls pretty much in the middle of the .014-.019 spec. I have aquired plenty of point sets over the years and should be good with those for the life of the car especially since it sees 1-3K mileage per year...

Jim

As usual, RapidRobert is on the money with his expertise.

Yes, your dwell decreased because of the increase in the gap. Dual point distributors came into being as a way to get more dwell (coil saturation) without doing it via a small point gap. Often, the "make" set can get by with a slightly closer gap and not show abnormal deterioration. If you see symptoms of weaker spark at the high RPMs, consider closing up the gap on the "make" set to get some dwell back (while leaving the gap on the "break" set alone).

At 35.5 dwell I would most likely leave it alone. Its close enough and as the rubbing block wears the gap will close up and give it more dwell. Its been a long time since I messed with points as I ran an Acell dual point up to 1982 and it ran very good with that dist. Dont forget to reset the timing when done setting the dwell. Ron

all good, except it's less gap=more dwell, more gap=less dwell...
Single points are usually set at .017-.019", and all points have to obey the same laws of physics, so you should be fine at 16. It's a bit tight, but I doubt this is a daily driver that gets tuned once a year @ 12,000 miles.
The 3 things you simply need to watch are point wear, misfire, and coil temps.

At some point I will get it to a drag strip for "official" times but the closest strip is almost 100 miles away. With the factory 6" steel rims and 225 red line radials behind a Dana 4:10, getting traction from a stop can be tricky. When I take my car buddies out for a ride I'll run it up to 25-30 MPH and then stab it. I still spin but not as bad from a stop. A few of them race pretty regular and have said it "feels" like a low/mid-13 ride. Typical response after a ride and mention of the points ignition is something like "Really??, no efn way...cool!". I know I can get better performance/less maintenance with an electronic version, but I won't get stranded when the orange box fails... I made the effort with this car to make it stock/functional as when new to see what the experience would have been like back in the day. Most every other Mopar I had was cold-blooded and difficult to start because I modified too much. This one has the carbs and choke set up correctly and all I do is give it two pumps with the gas pedal and then turn the key only to start it up. It goes to fast idle for a bit then tap the pedal and it settles down to normal idle. Brings a smile to my face every time...

Jim