The Stovebolt Site Forums The Shop Area Engine Shop 302 GMC AC Delco duel point distributor

I am in the process of installing a 302 GMC in my 1952 Chevy truck and just noticed that it has an AC Delco duel point distributor in it. Is this distributor stock or was it a high performance option you could get at the time. The distributor has an AC Delco metal tag on just like the distributor on the 235 Chevy engine that I took out of the truck but with a different part number. The distributor cap is also different (taller) and so is the rotor from the 235 distributor. What are the part numbers for the points, distributor cap and rotor if they need to be replaced? Also what is a dwell for a duel point distributor? Thanks for your help.

John

I'm guessing it has one of the dual point conversion plates in it that fit both the 235 and the 302 distributor. These do not use the same points as original, and they have to move the condenser to the outside of the distributor. It would be easiest to take the points out and take them to a parts counter to match them. The other possibility is that it is a corvette 235 distributor.

I have one of these plates in my 261. I usually set it so it has 10 more degrees of dwell than stock, and the way to set it is to first block the leading points (the ones that open& close first) open with a piece of paper, then set the timing and dwell to stock using the trailing points. Then remove the paper and adjust the gap of the leading points to make the dwell come out to around 43-45. The ignition fires whenever both the points are open.

4ontheFloor,
Thanks for the reply.
John

4ontheFloor,

I was just thinking. Would the box like covers over the points on my distributor be for radio suppression that would be required on a Corvette?

John

C195, I don't see any reason for extra shielding with an external ignition condensor. Corvettes needed the ignition shielding because of the fiberglass body. You have plenty of ferrous metal in your truck to provide radio noise suppression. Just keep the hood closed when you are listening to the radio with the engine running. If you have ignition noise in the radio, you might have to use resistor spark plug wires, or resistor spark plugs, but not both. I don't recall any particular radio trouble in the old vehicles that had metallic spark plug wires. I think resistor wire/resistor spark plug use was more to prevent interference with radio receivers located away from the vehicle.

Harvester

The stock radios shipped with a ignition capacitor and one for the generator. Make sure there is a points condenser either inside the distributor or outside before you go assuming the one on the coil is for the radio- you need one in the circuit somewhere, and with two sets of points there isn't enough room in the dist. body for a condenser.

Could you post a picture? Mine doesn't have covers over the points. You may indeed have a vette distributor.

I will try to post a photo this weekend. The distributor has a points condenser mounted on the put side common to the distributor cap spring clamp fastener.

C195, the additional ignition capacitor for radio noise supression goes on the coil positive terminal- and one on the generator armature terminal, as 4onthefloor mentioned. Those capacitors are slightly larger than the igniton capacitor at the points. I think the noise supressor capacitors are in the range of .47-.5 mfd. Delco igniton capacitors/condensors are .18-.23 mfd, more or less matched to the ignition coil. Don't connect a second radio capacitor at the points/coil negative terminal, or you will have an over-capacity condition for the ignition system that will cause severe metal transfer on the points- from the breaker arm contact to the fixed contact.

Harvester

Harvester,
The points condenser that I am talking about is attached to the outside of the distributor and the lead is attached to the input terminal where the wire from the neg. side of the coil is attached to that in turn goes to the points. There is no room for the condenser inside the distributor under the distributor cap.

John

No self respecting hot rodder could miss a Mallory dual point distributor setup. I had one in '64.

http://www.speedwaymotors.com/pl/393,6905_Chevy-6-Cylinder-Dual-Point-Distributor.html

Stuart

C195,
Ok, that capacitor is the ignition condensor. It may be larger (higher capacity) than the original ignition condensor, depending on the coil. Don't connect any capacitors to that side of the coil.

Harvester

I now know what kind of distributor I have. I have a AC Delco distributor with a Mallory duel point kit in it. The points have a number 25042 and the disributor plate has 2503 number on it. It also says to set the points with a .029 gap Are the points rotor and cap the same as the Mallory duel point distributor that they now sell? Attaches are some photos. I hope this works.

http://www.geocities.com/johnn1243/dist-2-s.jpg
http://www.geocities.com/johnn1243/dist-1-s.jpg

John

I would like to thank everybody who replied.

John

Looks like a good setup. Looks like you are off and running.

Harvester

That looks like you just need the regular cap and rotor. As long as both of them are either tall or short it will work. There are two heights available that fit the Delco distributor, as long as they are both one or the other no problem.