moisture in cap again

[flatmotor40]

Went for a ride yesterday to the store and to my Mom's house and when I got back in the 40 It started funny and started to pop so I stopped at Ingles parking lot to dry the dizzy out again seems everytime I let it sit a while it does this.It has a 2 bolt crab Mallory electronic dist in it.I think that I'm building up heat in engine compartment and when I shut it down it creates moisture in it because my electric fan never comes on.Is there anything that I can spray in cap or rub dielectric grease in it tired of this.Wil change the cap this week as I have a spare one see if that will help. Thanks for help

[Vic Piano]

You can use WD-40 on the cap. Is there a gasket that goes between the distributor housing and the cap that might be missing?

[fortyfords]

Sounds like you might have a crack in the dist. cap, it will be a fine crack

[ken ct]

Is the gasket on there under the cap and do you have the small rubber boots on the cap end plug wires. Or like someone said possible crack in the cap.ken ct.

[DICK SPADARO]

My advise is to drill a small 1/16" hole in the bottom( 6 o'clock point) of the cap just above the index ring line and allow the cap to breath.

[BUBBAS IGNITION]

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Spray WD40 inside and outside the cap ,,,,,,wipe excess off with rag , should fix it .....

[Torchie]

Originally Posted by BUBBAS IGNITION

Spray WD40 inside and outside the cap ,,,,,,wipe excess off with rag , should fix it .....

Exactly what this stuff is for.
WD40- Water Displacer. 40th formula revision.

[ken ct]

Thanks for the help on the shrink tubing Jim,much appreciated. Send an invoice with them. ken ct.

[flatmotor40]

I've tried with gasket and no gasket still does same.This is the dist that I sent you Bubba for the advance spring rusted into.I'll spray it down with WD40.Thought about rubbing diaelectric grease in cap but don't know if that will work.Have extra cap will put on this week.Car stays in garage covered up most of time with car cover.I thought that when it runs first time the heat from engine after shut down causes the moisture to build up since fan doesn't run.Thanks for help WD40 time

[Motorhead6]

Moisture getting into the cap indicates that it is coming from somewhere. Profound statement I know. Check to be sure that you don't have seepage coming from one of the thermostat housings, a radiator hose, a heater hose, or possibly a water pump slinging coolant up while turning at high speed. Re-tighten all of your hose clamps.

By the fact that you had a rusted spring inside the Dist., it seems that this has been going on for a while. Of course coolant with anti-freeze shouldn't cause rust, so maybe it's not that. Living in Ga where it is often very humid could mean that the cap "breathes" when it heats and cools, so look for a crack, hole, or opening in the spark plug cable receptacles. When the thing heats up, air escapes the inside of the dist., when it cools, it inhales moist air that then condenses the moisture out in the form of droplets that over time can become significant in quantity.

Working with hermetically sealed jet engine containers taught me that a slight leak over time can lead to large amounts of water accumulating in the bottom of the steel containers. I once saw a situation where there was maybe 30 gallons of water in a container that had sat for many years. It had only a slight defect in the seal and led to this.

[ken ct]

You never answered my question about the rubber boots theres 9 of them on there. 1 is for the coil wire.These have stopped many a water problem. ken ct.

[flatmotor40]

Yes the dist cap had MSD wires on it so all the boots do cover the cap.I'm thinking that when I first drive it it builds up heat in engine bay and as it cools down after sitting for a few minutes the cap was cold from sitting and it may have a small crack I think I may still have some die check that I used to use on aircraft parts left.But I'm going to change cap and soak the other cap with WD40.When I pull cap to wipe out the moisture is on the lugs inside cap.Thinks like this drives you crazy.But GM dist caps does not have a gasket and never a problem.I guess it is up on top not in frt of motor.Thanks again for talking about it Flatmotor40

[ken ct]

Dosen't seem to be a problem with the caps I use. USA made. Have 1 in Brown and the rest in black.?? ken ct. At least ive never had any complaints from anybody?

[koates]

Motorhead6 is correct, water/moisture is getting in from outside. Its a Mallory dist but I think it still should have a gasket between cap and dist housing and fit perfectly. I presume this dist is mounted horizontal in front of your flathead that's why it needs the gasket. It should also have a gasket between dist and engine. Does it have a vacuum connection, maybe the Mallory does not, but if it has check that moisture is not coming inside this connection from the inlet manifold. Possible, maybe. Remove dist from engine and check behind it for moisture. WD-40 is good but only a stopgap fix. Also because its an electronic dist it will have a small wiring condute wiring loom coming out the housing and going to the coil etc. Check that water is not getting in along this wiring to dist. Good luck, Regards, Kevin.

[Pete pa]

I have the same problem with my 40 coupe. It also has the Mallory dist. on a 59a motor. I tried using some silicone to seal the cap and also replaced the cap with a new one but the same thing happens when I drive it. I carry a roll of paper towels and when I stop I take off the cap and wipe it out or it will start to backfire or it will spark lock the engine when I try to start it. My springs for the advance were also rusted. I'm going to try the WD-40 fix and hope it works.

[flatjack9]

Seems odd as I've had my electronic Mallory in my 39 coupe for almost 20 years now with no problem except for an occasional cracked cap which I pretty much solved when I went back to a .025 spark plug gap.

[Bill OH]

I have Chrysler 360 ci marine engine with autolite distributor, cap has a seal, no vent, covers on wires and notwithstanding, moisture collects in the cap and makes the engine stumble after about two years of usage - remedy is to replace cap and rotor with a tan cap. I also oil the advance springs every year. Others have disclosed to me the same problem with marine distributors. I have sprayed the inside of the cap with brake clean - moisture returns - have not tried WD40.

But I have have had and also now have the 37 - 41 distributor that I can use a running garden hose on and no moisture problems - even had the side panels removed and rain got to the distributor and the engine started and ran fine.

[Rich Overton]

No one has mentioned CRC Marine ( green can ) I've had numerous boats used in salt water. Always sprayed ignition and all electronic connections with CRC, that is what it is designed for. Never had a wet or corrosion problem. You don't have to wipe it off either. Spray it on and go.
Rich o.

[Old Henry]

Sometimes when I've got some moisture in my upper distributor cap (it's the crazy double cap that's a nightmare to remove and replace) I just put a light bulb against it all night (turned on, of course) and it dries it out.

[flatmotor40]

I made new gasket yesterday and soaked the other cap in WD40 and it does have a drain or vent hole in bottom of cap so to me that said a gasket would not really be a issue since it has a hole in it as far as sealing it up tight.Maybe I just have a grimlin in this car but will spray it down with Crc if I can find it Thanks Flatmotor.I see I'm not the only one with this problem