Dwell Angle???

[55 Fargo]

Hi all, a few weeks back after discovering my engine was starting harder than usual I discovered thath the points were only at .010, and they should be,.020. This dwell angle point gap must have affected the timing of my engine, although it seemed to run well at this setting once started.

Last summer my engine was running warmer than I think it should have been, if my points were at .010, would thi affect timing enough to create the engine to run hotter............Fred

[greg g]

not likely, running th timing to far advanced can cause the running temp to raise a bit. The mopar cooling system is really an oversized unit, with a lot of fluid capacity. And because it is unpressurized its efficiency can be influenced by atmosheric conditions other than temperature, I wouldn;t be to concerned about your operating temp until you are driving the car more frequently and for longer distances. Plus you have a good 30 degree range which is condidered normal 160 to 190. So thee is really no need for concern unless you are running coniderably cooler ar hotter.

Wait till spring or summer drive it about 50 miles and see where it settles in.

[Dodgeb4ya]

Too small of point gap means large dwell angle which then causes slow ignition timing which then can cause more gas pedal application to get the rig going and this also causes combustion pressures/temeratures to be higher which loads up the compression rings and of course somewhat poorer gas economy and......................Well,,

probably good idea to check points and timing to eliminate all of the above!!

Bob

[55 Fargo]

Late last summer, it would settle in at about 175 or so, the aftermarket gauge would read 185,the temp in the top of the rad would be about 170, so somewhere in between that I would imagine.........Fred

[55 Fargo]

Thanx guys for the reply

[grey beard]

Free,

I noticed no one answered your original question, so I'll give it a try. Yes, dwell does affect timing quite a bit. Onan makes a pretty good fractional hp engine (18 tp 30 hp range) that is used a lot on gen sets and larger riding mowers. Their point setting is done with an allen wrench and a timing light - when the timing is correct and on the mark at idle, the point gap is correct., It is for this reason that tune up specs for most older cars with ignition points always tell you to set the points before the timing, because dwell does affect timing.

Having said all this, it is also my firm belief that there are more MoPar flathead engine problems caused by faulty centrifugal advance mechanisms than there are poorly adjusted points/timing issues. That centrifugal advance lies just beneath the breaker plate in your distributor, and is very subject to wear. To get to it, remove your distributor and the breaker plate asseembly. Then you can visually check the advance unit for slop and wear, There are two centrifugal weights and two springs. These must be in good shape if your engine is going to perform correctly.

Now, when you time your engine, make sure your idle speed is low enough that the centrifugal advance has not begun to operate, or your timing marks will be off. A good timing light has an advance meter built in - Pep Boys sells one for less than $100 that works well and has a digital dwell meter built in, as well as a tach. Using the advance meter, you can check out your centrufugal and vacuum advance curves. When both of these items are within spec, the difference has to be felt to be believed. JMHO:)