Condensation in distubator cap

Started by Learpilot, February 17, 2008, 10:29:05 AM

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Learpilot

This morning we had our weekly meeting of the Hot Rods for breakfast. We had our usual great time. When we were ready to leave the guy with the 34 Ford 3-window coupe's  engine would not start. It would turnover real good but not fire. He got out and said I know what the trouble is, it is water in the top of my distubutor cap. He got out his WD-40 like spray. He  took off the cap dried it out , then sprayed and it fired right up.  
He has had the problem a long time. He has a new dist. cap and rotor button.    
So it is not cracked.  
I think it is his plane side hood. No louvers to let out all the hot air. There is a lot of humidity here in Georgia. I think that hot air is trapped and when it cools down it forms moisture under the hood as well as under the cap.
What do you guys think about this ?
Thanks in advance for your answers !!!
Rick Harris

GPster

How does his engine run? I wonder if his vacuum advance diaphram is cracked and it's sucking outside air in. Can't believe thee's that much of an air change under the cap for moisture co condense. Maybe he should be checking to se4e if a Marine distributor cap is any different. GPster

UGLY OLDS

If it is a Gm dist look at the "base plate" for two small area's about 3/8" in diameter that should look like "screens"...  these are vents to resolve the issue you're talking about..The "screens" get a white "corrosion" looking substance on them that stops the air flow or "venting" of the dist cap...Some caps will have an 1/8" hole near the bottom for the same purpose....GM actually had a "bulletin" explaining how to resolve the "plugged" screens ...( You took a small screwdriver & poked a hole in them..Problem solved !) .. We saw that as being on the same level as the famous Chrysler "field fix" on lockup convertor "hunting" ..."Disconnect the convertor lockup switch & advise the customer that function no longer works on that vehicle" .....Incredible.... :shock:

Bob...
1940 Oldsmobile- The "Ugly Olds"
1931 Ford sedan- Retirement project

***** First Member of Team Smart*****

Bruce Dorsi

Does he wash his engine often?

We see this problem often at our carwash when people decide to wash their engines.

Drying the cap and spraying some WD-40 will get the engine running again, but unless ALL the water is removed from the distributor housing, it will condense on the cap again after the next cooling cycle.  (We use compressed air to dry everything inside the distributor.)

Engine heat will evaporate the remaining water, but if it is trapped, it will re-condense on the cap when the engine cools.  

As Ugly Olds said, the best prevention is VENTILATION of the distributor housing.  ....The moisture need a way to escape!
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If being smart means knowing what I am dumb at,  I must be a genius!

Dave

And if its an after market that doesnt have a vent hole then get the drill out or take out the dizzy then drill it..
Dave :wink:  :arrow:

Learpilot

His 34 runs great, no vacuum leaks or other problems. No car washing in the state of Georgia until we get out of  the current drought. He and the rest of us use a quick detailer to clean our cars until we can wash again.
He is using the big cap HEI dist. I am not sure about the vent holes you are talking about. I have them on my small cap HEI.
Thanks, Rick Harris

C9

I've seen new points type distributor caps right out of the box with a 3/16" hole drilled in them.

Usually between coil tower and the middle of two spark plug towers equidistant between all three.
C9

Sailing the turquoise canyons of the Arizona desert.

enjenjo

One other thing. If it's an older distributor, the bushings can wear enough that vapor comes up the shaft to contaminate the cap. There is also a felt seal that can be missing or dried out.
Welcome to hell. Here's your accordion.

Anonymous

Back in the day we would drill a 1/8 hole in cap at top.

Mikej

Quote from: "enjenjo"One other thing. If it's an older distributor, the bushings can wear enough that vapor comes up the shaft to contaminate the cap. There is also a felt seal that can be missing or dried out.


Might want to take a valve cover off to see it milky on the head or the inside of the valve cover. PVC valve? Not getting the engine warmed up enough to evaporate the moisture.

Learpilot

Quote from: "Mikej"
Quote from: "enjenjo"One other thing. If it's an older distributor, the bushings can wear enough that vapor comes up the shaft to contaminate the cap. There is also a felt seal that can be missing or dried out.


Might want to take a valve cover off to see it milky on the head or the inside of the valve cover. PVC valve? Not getting the engine warmed up enough to evaporate the moisture.
THANKS for all the suggestions !!! I will pass them along.