Join Date: Dec 2001
Location: Belleville, Illinois
Thanked 22 Times in 17 Posts
Use good-quality coil and plug wires. Clean them thoroughly with alcohol, spray them with silicone spray. When it dries as much as it's going to, spray them again. Make sure the boots have no cracks. When you install them make sure the wires are fully into the cap and onto the plugs. THEN push the boots on.
Make sure the cap and coil have no cracks or carbon tracks. Clean them with alcohol and spray the outside with silicone.
Check for any pathways for water to enter the distributor. The late-70's Autolite distributors had an exposed slot in the side for the linkage from the vacuum advance to enter. You need to make a cover and fasten it in a waterproof way. That's one place where a small amount of silicone caulk is OK since it should never need to be removed. Just let it cure for a day or two before installing it.
Some distributors have a vent hole in the bottom. That's a good idea for any distributor, but it needs a small nipple and a hose run to a dry place.
Silicone grease or dielectric grease is a good idea for the cap-to-housing seal. I use a Blackburn putty that an electrical lineman gave me, and it's never let me down.
I had a problem once when the vacuum advance diaphragm developed a leak. That let low pressure into the distributor housing, which sucked blow-by up from the crankcase past the seal. NOTHING I did helped kept the moisture out of the cap until I found the leak and replaced the diaphragm.