Case VAC Dwell

Does any one know what the dwell is supposed to be set at for a vac. I've read 60 for a 4 cylinder engine, but I was wondering if that varied any model to model. I left the ignition on on my VAC a few weeks ago and have since replaced every part of the ignition, but it doesn't run right. I'm thinking its the points. Any advice would be appreciated.

Thanks,
Lee

Didya replace the coil? The coil will get very hot and may overheat
if it happened to quit with the points closed & left with ignition on for hours.
Also, pull the wire off the coil that goes to the dist. and with the points OPEN
check continuity to ground. Should not be any continuity. On my VAC, the terminal thru the body of the Dist. ended up at the bottom, any moisture (condensation) would flow down around the insulated terminal, eventually creating a rust path to ground.
Sorry, haven't ever checked DWELL on these ole 4Bangers, just set points to .020 and go. I suppose there is an optimum setting but with only 4 lobes on the cam, there's plenty of time for the coil to saturate, at these RPM's.

how can you replace every part of the ignition, when the points is the first thing to look at? they probably burnt if they were in the closed position. install a new set and use a feeler guage to set them to factory spec and your good. spec is probably .020 as with most of these old engines. the dwell is checked after points are set, as we used to verify with the engine scope years ago. if the point gap is set correctly the dwell is also good. I remember .018 was 30 degrees of dwell.

I left the switch on, and came back a few hours later, no spark. I replaced the points (came with new rotor and condenser so I replaced those too) still no spark. I then replaced the coil with one off a 283 Chevrolet. It then had spark and ran but not well. A few days later I determined it was getting spark to the cap but not at the spark plugs, so I ordered a new cap. In the mean time I replaced the plugs and wires since I could get those locally. And I wanted to do that any way due to a mismatch of wires that were on it since I bought it. One note on this is that I replaced the plugs with D21 per the book, but it had D16. Yesterday after putting the new cap in it would run good for a while, then not. I would check/set the points again, then it would run for a bit then run like crap. Today same thing, I set the points, set the timing, it ran perfect for a minute then back to the same major misfire. Ive got a few other things to try, but Im running out of Ideas.

sounds like you are just throwing parts at it,, I am betting you have a bad connection between the breaker plate and the distributor, see it often,, anymore if they have Any corrosion/rust ect inside them I pull the plate and clean it all thoroughly, I have also seen the isolator on the distributor power post be bad and they will ground intermittently and drop spark, also see IGN switches be intermittent,, I learned 40 years ago how to test one with a test light to see where power is getting to and where its not on them,, saves a lot of headaches like you are fighting now, never was one to just start changing parts to fix a problem, I can say 100% you have not found your problem yet even with all you have changed even though it feels like you are gaining when you are not. Hope this helps as it can drive one Crazy when thye do not know where to look next,, seen it many dozens of times when I ran my shop,,
cnt

I did throw a lot of parts at it, but I was wanting to replace most of them any way. This morning I set the valves (something else I wanted to do since I got it in January) and set the points and it ran better than ever, probably mostly due to the valves being way off. However, the longer it ran the worse it ran. Eventually it was back to the misfire it had before. I played with the timing even tried setting the points intentionally off one way then the other, but no help. Sometimes it seems like it will idle ok but misses like crazy when I give it throttle. I checked continuity to ground with an ohm meter, with points open and closed both were as expected. I even tried putting the old plugs back in but no help. I used a timing light to "watch" the spark and it does seems to be a spark induced problem. The light doesn't flash when the tractor misses.

When I replaced the coil I added a resistor, 1.5 ohms per a discussion here. One odd thing I noticed, when I short the resistor it will sputter and die. This makes no since to me. Shorting from the battery to the resistor made no difference.


Sorry to be so long winded, but I'm at a loss. I may try putting the old points back in since it turned out the be the coil on the initial problem. The only other thing I would know to try is a new or different coil.

Thanks,
Lee

It can be a real challenge to get a good condenser any more.

I put the old condenser in today and it ran like a top. Thanks for the advise.

Lee