c2 coil and ballast resistor tests

[Larry Boden]

Hello All,
my 63 L84 is crapping out around 5g. I have just had the iginition and injector gone over by a pro, however off the car. He tells me it is either my coil (091) or my ballast resistor (black dot) Does anyone know a proper bench test that I can do with perhaps a volt/am meter? Seems to me there should be suggested specks on such things. Thanks in advance. Larry Boden

[Mike Cobine]

Re: c2 coil and ballast resistor tests

About the easiest and most reliable way is to change to a spare coil and see if that one works at above 5000 rpm. If it does, then your coil may be bad. If it doesn't, then you could have the condenser breaking down or the points bad.

The problem with most tests is if you are not running voltage and high RPM, then you could be missing when it breaks down.

And the coil could be failing from the engine heat, which you wouldn't see on a bench test.

[Mike Cobine]

Re: c2 coil and ballast resistor tests

About the easiest and most reliable way is to change to a spare coil and see if that one works at above 5000 rpm. If it does, then your coil may be bad. If it doesn't, then you could have the condenser breaking down or the points bad.

The problem with most tests is if you are not running voltage and high RPM, then you could be missing when it breaks down.

And the coil could be failing from the engine heat, which you wouldn't see on a bench test.

[William V.]

Re: c2 coil and ballast resistor tests

I have yet to see a ballast resistor cause a problem as described. I have always found them to be ok or open (engine will not run). I would be interested if anyone experiencing a ballast resistor that caused this type of problem. As mike said, I would suspect a point/condenser problem first and coil second.

[William V.]

Re: c2 coil and ballast resistor tests

I have yet to see a ballast resistor cause a problem as described. I have always found them to be ok or open (engine will not run). I would be interested if anyone experiencing a ballast resistor that caused this type of problem. As mike said, I would suspect a point/condenser problem first and coil second.

[Mike Cobine]

Re: c2 coil and ballast resistor tests

Bill is right, the points are the first place to go. Typically lack of high RPM is from burned points, wrong gap, or poor spring pressure. Corvettes ran a different set than the standard Chevy with a bit more pressure.

then condensers cause lots of problems, but usually only when they are relatively new or extremely old. I've seen ones used a couple of days to a week or two suddenly go bad. But if they make it longer, they seem to run forever. I hit a spot in the '70s that I wouldn't replace a condenser in a tune up becaue the likelihood of the new one failing.

Check that the points are gapped right and that they are not burnt. Once that is done, see if you can get more than 5000 RPM. Then a trick is to cut a piece of windshield washer hose about a quarter inch long, and set it behind the points to help keep them closed. If it runs above 5000, then your points have too weak of a spring. If not, keep looking.

You could even have fuel pump problems or fuel filter restricting flow.

[Mike Cobine]

Re: c2 coil and ballast resistor tests

Bill is right, the points are the first place to go. Typically lack of high RPM is from burned points, wrong gap, or poor spring pressure. Corvettes ran a different set than the standard Chevy with a bit more pressure.

then condensers cause lots of problems, but usually only when they are relatively new or extremely old. I've seen ones used a couple of days to a week or two suddenly go bad. But if they make it longer, they seem to run forever. I hit a spot in the '70s that I wouldn't replace a condenser in a tune up becaue the likelihood of the new one failing.

Check that the points are gapped right and that they are not burnt. Once that is done, see if you can get more than 5000 RPM. Then a trick is to cut a piece of windshield washer hose about a quarter inch long, and set it behind the points to help keep them closed. If it runs above 5000, then your points have too weak of a spring. If not, keep looking.

You could even have fuel pump problems or fuel filter restricting flow.

[William V.]

[William V.]

[Mike Cobine]

All you need is a matchbook cover

Geez, I thought everyone knew that!

[Mike Cobine]

All you need is a matchbook cover

Geez, I thought everyone knew that!

[Larry Boden]

c2 coil and ballast resistor tests

Thanks for the replys. The distributor just came off a machine and was teched to over 6K. I haven't tried a dwell meter assuming the dist was rebuilt properly. As I said all this was looked at by a very reliable engine tuner. If noone knows the bench test procedure I'll try another coil. ( i have a 60 fuelie as well but I know it has a different #. I'm assuming the 283 coil has a different config than the 327. Am I wrong?)
Best regards Larry Boden

[Larry Boden]

c2 coil and ballast resistor tests

Thanks for the replys. The distributor just came off a machine and was teched to over 6K. I haven't tried a dwell meter assuming the dist was rebuilt properly. As I said all this was looked at by a very reliable engine tuner. If noone knows the bench test procedure I'll try another coil. ( i have a 60 fuelie as well but I know it has a different #. I'm assuming the 283 coil has a different config than the 327. Am I wrong?)
Best regards Larry Boden

[Duke W.]

Re: c2 coil and ballast resistor tests

Are you running the high breaker arm tension points? How much shaft end play? Side play? How old is the breaker plate? Is it nice and snug or does it wobble?

"Bench test" - free rev the engine to 6000 with a dwell meter attached. If the dwell varies by more than 2 degrees the distributor needs work.

What did the "pro" do to the distributor?

I would thoroughly check out distributor operation before you suspect the coil or ballast.

091 coil primary and secondary resistance is in the specifications section of your'63 Corvette Shop Manual. Ballast should be about 0.3 ohm at room temp.

Duke

[Duke W.]

Re: c2 coil and ballast resistor tests

Are you running the high breaker arm tension points? How much shaft end play? Side play? How old is the breaker plate? Is it nice and snug or does it wobble?

"Bench test" - free rev the engine to 6000 with a dwell meter attached. If the dwell varies by more than 2 degrees the distributor needs work.

What did the "pro" do to the distributor?

I would thoroughly check out distributor operation before you suspect the coil or ballast.

091 coil primary and secondary resistance is in the specifications section of your'63 Corvette Shop Manual. Ballast should be about 0.3 ohm at room temp.

Duke