Nailhead Heat Tube

Discussion in 'Carter' started by Briz, Nov 28, 2019.

  1. Briz

    Briz Platinum Level Contributor

    On the 66 Cat w/ 401 I need a heat tube that runs from the choke through a tube in the R exhaust manifold. The sleeve in the manifold is clear and not compromised. If I cannot get a new tube a good picture of a complete one should be enough for me to see how to make my own. Have been unable to find a replacement through the usual vendors
  2. cobravii

    cobravii Well-Known Member

    I used brake line and bent it fit with a compression nut on the choke end. I also purchased the fabric covering for it (from I think) Buick restore 114.JPG
  3. Briz

    Briz Platinum Level Contributor

    Thanks for that. For now I have the single carb. Also noticed in one of the online pictures while researching a line that was plumbed into the intake below and to the rear of the carb pad that looked like it was running straight down and behind the exhaust manifold. My thinking was that it was a vac line but I'd have no idea what it was for.
  4. wkillgs

    wkillgs Gold Level Contributor

    Here's my '66 GS with Q-jet. The lines are a duplicate of the originals. Note the other line above the choke. That runs to the same exhaust manifold heat pipe. It's purpose is to supply filtered air to the rear of that pipe, then the front end gets plumbed up to the choke where the warm air gets pulled into the engine via vacuum port.
    The steel vac line you saw at the rear of the intake likely goes to the vacuum modulator on the trans.
  5. Briz

    Briz Platinum Level Contributor

    Looks nothing like what I envisioned the set upon my 401 car would look like. Maybe different for the 401 and carter carb. The places for the hot air tube to attach is in the rear of the exhaust manifold just above the down pipe mounting flange. I'll probably;y just have to wing it
  6. SpecialWagon65

    SpecialWagon65 Ted Nagel

    I can get a picture together Sunday when I get to the garage... carter carb clean air comes from the fitting @ rear corner of the carb.
  7. Wildcat GS

    Wildcat GS Wildcat GS

    Vacuum line for the trans modulator. There is a dedicated nipple for the modulator vacuum line on the intake manifold in `66
    Briz likes this.
  8. Wildcat GS

    Wildcat GS Wildcat GS

    Did you look for an illustration in the shop manual?
  9. telriv

    telriv Founders Club Member


    On the right side rear on top of carb. on an angle to the right is the fresh air connection for the choke. This has a brass looking piece of pipe coming from it. It goes under the exhaust manifold below the bottom in the center. You connect the pipe with a piece of 1/4" vacuum hose. As this part does not get hot as it only supplies fresh clean air for the choke.
    On the right rear of the manifold is the hot air supply connection that goes to the choke housing. This is what supplies hot air for the choke to operate. When you start the car there should be vacuum sucking on the nipple from the choke housing. IF it is not you need to remove the choke housing from the carb. & reseal the vacuum port or clean the gunk out of it.
    To remove the broken/rotted piece of tubing from the rear & bottom of the exhaust manifold use a drill smaller than 1/4", or slightly larger than 3/16ths. & drill the broken/rotted part out. DON'T drill any deeper than about 1/2"or you will damage the stainless steel packing in the tube to slow the fresh air coming in to properly heat the choke housing. This will leave a little piece in there that can be snaked out with a pair of pliers or the end of a screwdriver. Insert the 1/4" OD tubing in the bottom & top holes. You can use aluminum, steel or copper plumbing line for this purpose. Copper is easy to bend & won't rot out. On the hot air supply use the covering used on the Corvettes available from various suppliers which is mostly the proper length & original looking material.

    Tom T.
  10. Briz

    Briz Platinum Level Contributor

    Opps. to late. drilled through end to end. I have some stainless screens I can roll up and stick back in there. Had no idea it was important. Thanks for the info!
  11. Wildcat GS

    Wildcat GS Wildcat GS

    Lol...yes, I made the same mistake many moons ago...if my recall is correct the insert inside the tube is like a twisted dipstick, makes perfect sense to slow down the traveling air column to transfer more heat.
    Did you find a diagram of the original routing? Thought that is what you were asking originally...
    Tom Mooney
  12. Briz

    Briz Platinum Level Contributor

    That was the question and as of yet no. I did get the heat riser free'd up and functioning. heat the spring with hot air and it opens. cool it with compressed air and it closes.
  13. Bigpig455

    Bigpig455 Fastest of the slow....

    The choke air tube will send hot air to the carb without a functioning heat riser..
  14. Briz

    Briz Platinum Level Contributor

    I guessed it would but if Im in there why not make it work. Just waiting on the exhaust locks to come in to swap the manifolds
  15. Briz

    Briz Platinum Level Contributor

    I found one in the last place I'd ever think of looking for one, in my shop. Replaced the exhaust manifolds and once all the really loud leaks were sealed up I heard another. The disk in the bottom of the intake manifold was rusted out. No problem, I have the parts engine that the exhaust manifolds came off of! Pulled it down from the shelf and started unbolting the manifold and found the tube as well as another oddly shaped pre-bent tube on the valley pan buried in dirt and mouse nest. Its complete except for where it rusted off the R ex manifold. I think I'll remake it in either stainless or copper. Might even make a few extras to list in my store.

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