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Technical Thickstun Head Covers

Discussion in 'Traditional Hot Rods' started by 35cab, Mar 16, 2014.

  1. 35cab
    Joined: Jan 5, 2011
    Posts: 243

    35cab
    Member

    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.
     

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  2. 35cab
    Joined: Jan 5, 2011
    Posts: 243

    35cab
    Member

    . . . . anyone ? . . . .
     
  3. JeffreyJames
    Joined: Jun 13, 2007
    Posts: 16,598

    JeffreyJames
    Member
    from SUGAR CITY

    Are the actual heads underneath cast iron or Aluminum?
     
  4. 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!!
     
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  5. JeffreyJames
    Joined: Jun 13, 2007
    Posts: 16,598

    JeffreyJames
    Member
    from SUGAR CITY

    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.
     
  6. flatjack
    Joined: Feb 13, 2007
    Posts: 876

    flatjack
    Member

    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.
     
  7. 35cab
    Joined: Jan 5, 2011
    Posts: 243

    35cab
    Member

    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.
     
  8. flatjack
    Joined: Feb 13, 2007
    Posts: 876

    flatjack
    Member

    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.
     
  9. tommy
    Joined: Mar 3, 2001
    Posts: 14,758

    tommy
    Member Emeritus

    They were made for boat racing so that the spray would not short out the plugs.
     
  10. 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.
     
  11. Never gets hot enough in Oshkosh to be a problem....LOL :eek:
     
  12. 19Fordy
    Joined: May 17, 2003
    Posts: 6,557

    19Fordy
    Member

    35cab, I like your spark plug wire looms.
     
  13. mechanic58
    Joined: Mar 21, 2010
    Posts: 681

    mechanic58
    Member

    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.
     
  14. alchemy
    Joined: Sep 27, 2002
    Posts: 14,732

    alchemy
    ALLIANCE MEMBER

    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.
     
  15. 35cab
    Joined: Jan 5, 2011
    Posts: 243

    35cab
    Member

    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.
     

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  16. 36tbird
    Joined: Feb 1, 2005
    Posts: 1,083

    36tbird
    Member

    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.
     
  17. flatjack
    Joined: Feb 13, 2007
    Posts: 876

    flatjack
    Member

    I wish. Our winter has been so cold that I'm afraid the summer might try to average out the temp for the year.
     
  18. flatjack
    Joined: Feb 13, 2007
    Posts: 876

    flatjack
    Member

    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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