distributor help.. rebuild or get a new one??

[green1970]

my 302 on my 1970 truck is midly built and i rebuilt the distributor a few years ago along with the motor. i recently had pulled out the motor to repaint and to paint my firewall because the master leaked and peeled off my paint. when i washed the motor, i covered up the dizzy. put the motor back in, and it missed. cleaned the pluggs and two of them didnt look like they were firing well. after i cleaned the plugs, i drove it for a day and it started missing again. i think i may have gotten water in the dizzy. should i just rebuild this one or just go ahead and get a new one. i was thinking a mallory or MSD dual point, or going electronic. what do you guys think?

[averagef250]

There isn't much to a dizzy. Couple bushings and some washers/shims. You don't need a new one unless the shaft is sloppy. There should be some up and down play, side to side should be very minimal though.

If by rebuild you mean replacing points/condensor/cap/rotor that's just tune up stuff. If you're running points do your truck a favor and swap to duraspark from a newer carbed 302 truck.

[FORDification]

Is your present distributor electronic or with points? It really doesn't matter, I guess, since a little water isn't going to kill a distributor...it just won't run well until it dries out. Once it's dried, it's just fine. If the distributor is electronic, I suppose there's a very slight possibility of a tiny hole in the pickup, allowing some water to get inside and shorting something out, but I've never heard of that happening before. Even so, you'd simply need to replace the pickup. If you rebuilt the distributor only a couple years ago, there's still plenty of miles left on it, so unless you're looking for some serious upgrading, I don't see it as cost-effective to completely replace it now....especially since I doubt the distributor is causing your problem.

You didn't mention what two cylinders were going bad....how correct would I be by guessing that on your FE, it's cylinders 7 and 8 (the back two on the driver's side)? If so, then the problem is likely caused from the engine "cross-firing". Certain plug wires touching each other on adjacent cylinders in the firing order will cause a no-fire (or cross-fire) condition in that cylinder, and create the fouled plugs. Cross-firing results from the magnetic field produced when an electrical current passes through a spark plug wire, causing two cylinders to fire at the same time. If cross-firing is allowed to occur, one cylinder has the spark plug firing ADVANCED 90° from the proper time. With that amount of ignition advance, it is only a matter of time until a component will fail. This is a known problem, and many service bulletins from all car manufacturers have been issued regarding this problem on various engines, depending on the firing order. Here are the Ford engines mentioned that have been identified as being susceptible to this condition:

Ford Engines (221-302, 332-348, 370-460) - 1-5-4-2-6-3-7-8
Ford Engines (302 HO, 351-C, 351-W) - 1-3-7-2-6-5-4-8

Try adding some additional plug wire separators and routing them through the separators as in the graphic below, which I just scanned from a Ford Training manual.

[green1970]

thanks keith!! i really have never though about the wires touching and cross firing.. i cant remember which two cylinders it was but i will check on that this weekend! sounds like it could be the problem because im running points and they should be dried out by now..