distributor cap moisture

[dcasalena]

I recently started covering the truck with a high quality cover to keep the spring sap from dripping all over her (or it, I haven't given a name yet).
After the first rain with the cover, the engine was soaked with condensation (and the body was dry). Cover worked great, but now it won't start, cranks but no fire.
I like to start with the easiest and cheapest solution first, so I'm guessing that condensation got inside the distributor cap. I've read some posts that recommend using a solvent/spray to remove the moisture from inside the cap. What do you guys recommend I use. My local Napa guys might not have a recommendation when it comes to a 40 year old system with points and a cap so I'd like to go in with an exact solvent/spray I can ask for.
Also, anything I need to do to insure everything sparks in the right sequence if I remove the cap, dry it out, and put it back on?

[geezer#99]

WD40 works the best.

[Autoblueprint]

Originally Posted by dcasalena

Also, anything I need to do to insure everything sparks in the right sequence if I remove the cap, dry it out, and put it back on?

Should be able to pull distributor cap off far enough to expose inside of cap and distributor body to dry it out with compressed air at 40 psi max...if you are not sure of firing order then mark your wires with tape and the mark #1 cyl spark tower on cap if you have to remove the wires.

BTW : good time to install a new cap and rotor if you do take wires off or go all out and replace with HEI set-up.

Originally Posted by geezer#99

WD40 works the best.

Externally.

[geezer#99]

Wd 40. Used internally. WD stands for water despersant. It's not for loosening rusty bolts and nuts or for penetrating fluid even though some use it for that.

[BLACK AND BLUE 67-72]

Yes spray WD 40 inside your cap wipe off the excess and our good to go!!! I use it all the time and have had no problems!

[dcasalena]

WD-40 is water displacement, but it's also a lubricant which I would tend to think means it leaves a film of something behind. Maybe this film of lubricant burns off? It's worked for you guys for years so I'll go with it.

Follow-up, if I replace the cap AND rotor, what do I have to do to insure timing is correct? Do I have to rotate the engine to tdc and position the rotor correctly?, or is that not necessary, or is there a shortcut like marking where the old rotor was positioned and putting the new at the same spot?

[geezer#99]

Why add more problems. Pop each plug wire off gently one at a time, spray it and put it back on. Move the cap enough to spray wd40 inside, put it back in place and see if it runs.
You can change the rotor and cap later if needed.
What kind of distributor you got. Points or HEI.

[NoNeck]

Replacing the cap and rotor are pretty straight forward.

Leave the spark plug wires on the cap. Loosen your old cap, and pull it up and forward enough to get to rotor.

Make note of the direction the metal tip on the old rotor is pointing. Remove the two screws holding the rotor button. Pull it straight up. You will notice that there are alignment tabs under the rotor that fit only one way. Point the metal tip in the same direction as the old rotor and the alignment tabs should match. Push the rotor down in the tabs, and replace those two screws. Your rotor is now on.

The cap will also only go on one way. If you have the metal window in your cap for adjusting points, that is the front. If not, all caps have a little square tab that positions the cap correctly on the dizzy. There is a notch on the base of the housing that this tab fits into. Install the new cap and spin the hold down ears under the housing.

Hold your old cap in the same positon of the new cap, and move one wire at a time to the corresponding terminal on your new cap.

You should be good to go.

[Lippyp]

Yep, WD40 works well, my 4x4's always had a good dousing of the stuff over any electricals under the bonnet (hood) once its dry I also like a thin smear of grease (vaseline works well) around the bottom edge of the cap before it goes back on, stops moisture getting in. You used to be able to by aerosol sprays of ignition sealer, it was kind of like a flexible soft varnish that you spryed over the whole distributor etc and it sealed any small cracks. I had a MK1 Vauxhall Cavalier that was a pig for spluttering to a stop if you went through a deep puddle due largely to the stupid positioning of the dizzy, a good spray with the stuff stopped it happening for good. Probably no longer available now as most modern ignitoon systems don't seem damp prone, that was back in the mid 80's.

[dcasalena]

Thanks NoNeck, makes it sound easy.
Thanks Lippyp I'll use the vaseline tip too.

[68gmsee]

I wish you luck but if it doesn't help you may need to do what I did on a 76 Dodge van I had.

Every time it rained or we had a very foggy night, condensation got trapped inside and I had to yank the inside cover off and dry it off. I tried a new cap and rotor and solvents and didn't help. I finally got a small tube of sealant (don't remember which kind) and laid a thin bead along the edge of the dis and cap and never had trouble again.

[Eddie H.]

I used to have an old 69 ford that wouldn't even start on a humid day. (Heck, a dog could pee on the wheel and it wouldn't start.) I carried a can of wd 40 with me all the time to dry out the distributor cap. It works better than anything else I've ever used.