Opened the hood on our 76 yesterday to recharge the battery and noticed the engine was soaking wet due to condensation. There was a pool of water where the distributor sits and all the wiring was dripping. Has anyone found a good source for under-hood insulation? Cheap? How would you attach the insulation?

 

So, is the topic the soaking wet engine or the insulation ?

 

If it's truely condensation then insulation or rubber sealers around the hood (I assume that's what you mean) isn't going to stop it. Condensation is water vapor that settles on solid objects and cools into liquid water (most often after a storm, or in highly humid areas. It will come up from under the truck, through the grill, from anywhere. Not much you can do about it.

 

Thank you Gentlemen, let me rephrase. Why do we have a soaking wet engine in our 76 F250 when two other family vehicles have almost no water in, on and around their engines? The two other vehicles both have thick under-hood mats. All three vehicles are sitting outside in the same climate (rain, fog, 100% humidity). One of the other vehicles is driven daily but the other one sits just like the F250. When you open the hood on the Ford, a huge amount of condensation is hanging from the underside of the hood (not so in the other 2 vehicles). My experience with condensation tells me that it forms on the warmer side of a barrier - for example the inside of single pane windows. So insulating the underside of the hood should reduce the condensation. Is my logic bad?

 

Your logic is not incorrect, but your premise is.
You are assuming condensation forms on the warmer side, when if fact it forms on the cooler side of an object. In your example of the window, the warm moist air contacts the cool glass, and cools down. Cool air cannot hold as much water as warm air, so the water must leave - rain in the case of clouds, condensate in the case of cooler objects.
Condensation forming on the insides of these old trucks is due to several things. Those old motors are very large compared to smaller ones; the much heavier mass does not adjust to ambient temperatures as fast as the lesser mass in smaller ones. Second, they are much more open to the atmosphere than smaller cars, the air flows freely aroound under the truck and up into the engine bay. In this respect, smaller cars don't have the same airflow because so much is packed into the engine compartment.
The condensate does not form on the sheet metal because it is able to quickly gain or lose heat due to the smaller mass. (Although, this can happen if the weather change is rapid and dramatic enough.)
Be aware that the condensate is forming directly on the engine, wires, etc. It is most likely NOT forming on the underside of the hood and dripping down.

This phenomenon most often occurs when an extended period of cool or cold weather is rapidly followed by very warm (comparitively) and very moist weather. I used to experience this a lot with my '66 when I lived in Tacoma, WA, and occasionally experienced back home in SC, especially in the mountains.

Hope this helps.

 

Just a theory; if the moisture from the ground was drawn to the cold hood and formed ice, then the sun hit the hood and melted the ice you would get a wet engine. If the hood were insulated then the ice would take longer to melt and the air may take the moisture away before it formed drops and dripped on the engine.

end of theory

 

Banjopicker66 is right on the money. The more air that can flow around the engine allows more moisture to collect. In the past I have had rebuilt engines on the stand which sweated. The weather had been very cold and then a warm front would come through and the engines got wet. Just like the cold beer you pull out of the refrigerator sweats.

Anyway, on the same days that my rebuilt engines sweated, the engines in my cars and truck were sweaty. My 76 F100 has an FE which is not in an insulated engine compartment. All of my cars set outside while my rebuilt engines were inside my storage building.

Another possibility is that an engine that is used more frequently is less likely to develop moisture over a period of days like another which is not used much.

 

Vancouver BC is a humid climate.

People don't get suntans there ....they rust !

Insulation on a Hood promotes rusted hoods.

The more air circulating around the engine compartment the better.


I don't know where in Van you live but,
Has this truck been parked in a shady, sheltered from the wind spot ?

If so, point the grill West so air can circulate under the hood.
Popping the hood a few inches should help as well.

 

Wow, thank you Mil1ion, Polkat, Purely Ford, EricJ & banjopicker66, I really learned some applied science here. Yes, the F250 has a (monster) big block with enormous mass and the engine compartment, as you all know, is big enough to have a Polish wedding inside! Yes, the truck is parked up against and into a blackberry patch and is standing on wet gravel. The drier vehicles are standing on concrete - I didn't think of that difference. So, I won't try to insulate the hood and will move the old girl to a draftier spot on concrete. Maybe she can face into the wind too. Once again thanks, this was useful! By the way Mil1ion, I did get a minor sunburn once in the summer of 68, we had 20 minutes of uninterrupted sunshine on July 19th just after lunch - people still talk about it around here.

 

The 73-79's are also famous for rain water running between the cowl and hood, running down the underside of the hood, and dripping on the engine. This is the most likely cause of water on an engine where I live.(Texas) I bought the cowl weather strip from LMC to fix the problem... JUNK!!! It fits poorly, won't un-wrinkle, and does not seal. I'd suggest some self adheasive rubberized weatherstripping from a home improvement place. Cheap, easily replaceable, and effective.

 

Yes good idea DerrHerr65, my hood/cowl weather strip is nonexistant. The problem is the hood doesn't fit properly - got pranged on the right front - so the hood doesn't come down to meet the cowl right. Just another 30 minute job that will take me forever to fix.