I have a pair of repro Thickstun Head covers on my 35 (French Flathead, 48 trans and Columbia rear.) I don't always run them, particularly on long trips, the Columbia gives me a good top end, but it seems to run hotter with them on. I have always wondered about the possible heat build up, even thought about venting them front and back, but before I do this, anyone had any experience of the covers causing increased temperature? Thanks, Gordon.
They're kinda like wearing a ski parka in the Sahara Desert, don't you think? I have always loved parts that had no practical value!! LOL!!
Except maybe for a hoodless car that doest want to drown the spark plugs. These were initially designer for marine applications correct? I would think that if the heads were aluminum and the covers were as well they would get rid of the heat as quick if not quicker then cast iron heads alone. But who knows.... Maybe the originals had some trick up their sleeve.
I've been running the reproduction covers in my 39 coupe for almost 20 years now. Absolutely no overheating problems. I've probably got close to 50,000 miles with them on and they are always on.
Thanks for replies. I know they are kind of useless, they do spiff up the engine, I am running stock iron heads so maybe they are just vanity, under a full hood it probably does not help. Flatjack, do you have iron heads under them? Thanks.
Yes they are iron, a set of 81A's. I didn't want to put finned heads on and then cover them up. They do look cool and confuse a lot of people unfamiliar with them.
I ran a flathead in a boat (Crackerbox class) for a couple of years. The biggest problem wasn't getting the spark plugs wet, but the distributor!! We cut an old piece of inner tube to put over the distributor and never did cover the spark plugs. Not pretty (LOL), but it worked.
One of the best insulators in the world is a dead air space between whatever it is you're trying to insulate and the atmosphere. In this case, the cylinder heads have an air space between them and these covers. There is no doubt in my mind they are contributing to your heating issues. The only way you could eliminate it is to somehow make the covers have FULL contact with the iron cylinder head - then they would function as a heat sink, instead of an insulating device. E.G. Double pane windows.
Thickstun head covers are supposed to fit over Thickstun heads. And Thickstun heads have little round pads in the corners for the covers to sit on. But there is a gap all the way around the edge between these small pads. Maybe when guys put the covers over their Ford heads they fit too tightly. No gap to allow any airflow.
Thanks Guys, Some food for thought. I had not realised Thickstun heads had pads so I can see how that would make a difference. Good point about the insulating properties of that trapped hot air. I have a plan to maybe vent the rear edge to allow hot air out, perhaps even matching that at the front. I know these things are just a bit of an indulgence and venting them kind of defeats the idea of the intended function, but under a full hood protecting the spark plugs from rain is not a problem, even in Scotland! 19Fordy, thanks for compliment on spark plug wire tubes, can't take credit for them, my friend Pete made them for me. Thanks for input everyone.
Don't mean to brag, but I've got two flatheads that run so cool here in south Texas that I have to use 180* thermostats to keep them up in a good operating temperature zone. So, what I'm trying to say is that if your cooling system on the f/h is all good, you would not see any detriment from these covers. Wish I could find a pair 'cause they are really neat.
I wish. Our winter has been so cold that I'm afraid the summer might try to average out the temp for the year.
You must be kidding. There is no way that the repro covers seal off the head. I've driven the car many times in 90+ weather without a problem. Any cooling problems are not being caused by his head covers.
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