2 Sets of burned points in less than 300 miles

[Jeff C.]

Hi,
1963 340 HP
Several months ago car started missing in normal driving.
Reset dwell and timing no improvement.
Pulled distributor saw burned points but everything else looked good except points. Finally found bottom shaft bearing was oblong with lots of movement.
Replaced with new rebuilt distributor with new, points, condenser, spark plugs, coil and spark plug wires.
Car ran best it ever has for about 100 miles then back to serious missing. Burnt points again.
Pulled distributor double checked everything including coil. spark plug wires etc.
The amp gauge has not reading high but I am replacing the regulator, horn relay and of course the points with new ones. The altenator was rebuilt 2 years ago by John Pirkle and has work fine.
Before I start the car again am I missing anything?Thanks,
Jeff

[Bruce B.]

Re: 2 Sets of burned points in less than 300 miles

Is the ballast resistor OK?
Sounds like the points are getting full voltage after starting.

[Tom K.]

Re: 2 Sets of burned points in less than 300 miles

Have you replaced the condenser? If they go bad they will burn the points. Also is there voltage to the points after the key is turned off or have you left the key on without the engine running? This will also burn points. Running voltage to the points should be about 8-9 volts if I remember right. Hope this helps
Tom

[Dan P.]

Re: 2 Sets of burned points in less than 300 miles

check make ground connections are good

[Duke W.]

Re: 2 Sets of burned points in less than 300 miles

Burned points happened once to my '63 340 HP. That's why GM ended use of the 0.3 ohm ballast. Check yours and if it's the original type replace it with the standard 1.8 ohm ballast.

Checking wiring/coil voltage as previously recommended should be done.

Also, what about the coil? The original 0.3 ohm ballast was used in conjunction with the 091 coil. When the 1.8 ohm ballast replaced the 0.3 ohm ballast as a running change to 250/300 HP engines during '63 production they also changed the coil to the 087. I'm not sure what the difference is, but they may have different primary resistance values.

Duke

[Ray C.]

Re: 2 Sets of burned points in less than 300 miles

I had the same problem using a reproduction black dot 0.3 ohm resistor, I changed to the 1.8 ohm and have not had a problem since. Good post Duke!

[Jeff C.]

Re: 2 Sets of burned points in less than 300 miles

The ballast resistor is marked .2ohms and tests to that. Had not caused problem before this. Where can get a 1.8ohms one?
Thanks
Jeff

[Frank D.]

Re: 2 Sets of burned points in less than 300 miles

The ballast resistor is marked .2ohms and tests to that. Had not caused problem before this. Where can get a 1.8ohms one?
Thanks
Jeff

IIRC there is a TSB on this topic in the back of the latest 63 Judging Guide...specifically for burned points.
Long Island Corvette part 37-25A is the repro 1.8 ohm, blue stripe, ballast resistor..

There is a "supposed" NOS one on ebay:

https://www.ebay.com/itm/1963-67-Corvette-NOS-Ballast-resistor-Delco-D-1110-in-GM-box/263428580854?hash=item3d559125f6:g:9VcAAOSwS~FaVaAy

[Duke W.]

Re: 2 Sets of burned points in less than 300 miles

You can buy a generic, functionally correct 1.8 ohm ballast at any parts store, but, of course, it won't judge as original because of different appearance. If you go for NOS or used, it will probably be more expensive, but remember this part was used on virtually all GM cars with single point ignition so you shouldn't have to pay a "Corvette" price.

Duke

[Jeff C.]

Re: 2 Sets of burned points in less than 300 miles

So I finally saw why I paid almost twice as much for the 63/64 judging manual. I'm getting a 1.8 resister however the tech bulletin said the fix was for cold weather and if applied to the high performance engine's it would not deliver the best performance. OK, so I am just being a s__t.

Sorry
Jeff

[Duke W.]

Re: 2 Sets of burned points in less than 300 miles

The lower ohm ballast delivers more spark energy, which means less with the high ohm ballast, so it might not be able to fire a fouled plug as well as the low ohm. Burned points were more common in cold weather, but could happen in mild weather, too.

For '65 all engines with single point ignition used the 1.8 ohm ballast and ...202 coil including L-79.

Suggest you buy an inexpensive generic replacement 1.8 ohm ballast and see if it solves the problem. If so and you want NOS or good used original so as to not take any points deduction, that's your choice.

Duke

[Jeff C.]

Re: 2 Sets of burned points in less than 300 miles

Thanks,
jeff