How do you test a coil??
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
You can do a continuity check on both windings using a simple VOM. If that fails, don't bother going any futher.
If it does seem OK, the only way to full test it is to install and go for a good long drive. Bring a spare as a back up.
Static checks done at room temp frequently do not flush out weak coils.
If it does seem OK, the only way to full test it is to install and go for a good long drive. Bring a spare as a back up.
Static checks done at room temp frequently do not flush out weak coils.
Burning Brakes
Joined: May 2004
Posts: 1,100
Likes: 3
From: belle plaine ks
tester
I have a tester out in my garage that done it. It would heat the coil up for a few minutes and then it had an air gap between two posts with a *** on one post. You screwed the air gap farther apart until the spark failed. Then you read on the face of the tester under where the screw stopped to see if your coil was good. It worked fairly well as it could eliminate a coil pretty quickly as being good or bad. I don't think they make the thing anymore as coils are almost non existant as points are eliminated. The coils they use today on electronic ignitions are not like the oil filled ones from the 50's and 60's. The modern day ones are probably checked using a multimeter and no physical "load" is tested like the tester I have.
Drifting
Joined: Jan 2006
Posts: 1,944
Likes: 22
From: Yooperville MI
The typical method to bench test it is using an ohm meter. With the coil disconnected, measure resistance between (+) & (-) terminals; the reading for a points type coil should be about 1.5 ohms. To test the secondary; measure between the tower and the (-) terminal and you should have between 4,000 & 20,000 ohms. An infinite reading on either indicates an open in the windings and readings beyond those parameters indicate a faulty coil. There should be no reading between any termainal and the case. A coil could have a heat related problem and still pass the tests.
