Register now to get rid of these ads!

Technical Exhaust Manifold Leak

Discussion in 'The Hokey Ass Message Board' started by Truck64, Jun 6, 2017.

  1. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547

    stimpy

    those are the ones that I ran across . we annealed them with a torch ( have to a oxy with a rosebud tip ) the old timers showed me how to do it . you soot them up with the carbon , then use the flame to burn the soot off and let them sit in a draft free area .
     
    Truck64 likes this.
  2. Truck64
    Joined: Oct 18, 2015
    Posts: 3,854

    Truck64
    Member
    from Ioway

    Well I have a pretty good straight edge I guess, one of those big steel carpenter L deals. I use it to make sure the relief is correct on guitars. I sort of checked the manifold the last time But I don't know what I'm doin'. I'll call around and check and see if there's anybody left.

    One thing. A tick under load would be the manifold itself right? The connection at the exhaust tube to manifold might be a little sketchy, I sealed that up as well as possible. I figure it would sound different. I'll see if I can't find evidence of the leak. Some suggest stuffing a rag in the exhaust and they are easier to find, that seems like that would be a two man job to work best.
     
  3. Truck64
    Joined: Oct 18, 2015
    Posts: 3,854

    Truck64
    Member
    from Ioway

    Propane torch wouldn't work?
     
  4. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547

    stimpy

    not hot enough also the soot burning off tells you its temp . it takes around 650-700 degrees . a tempique marker possibly be used but to get the heat even s the trick .
     
    Truck64 likes this.
  5. squirrel
    Joined: Sep 23, 2004
    Posts: 44,287

    squirrel
    Member

    I use a few feet of heater hose as a stethoscope to pinpoint sounds like that.

    The heat shield looks like the style they had on some of the Dodge LA engines around 1970, it's embossed sheet steel. When a bolt gets loose, it burns the gasket area. And they are not real good for multiple uses, either.

    But yeah, listen for the sound, you should be able to figure out right where it's coming from
     
    Truck64 likes this.
  6. Gene Boul
    Joined: Feb 9, 2006
    Posts: 807

    Gene Boul

    Obviously (as above) sum ting wong. Manifold is not flat soo take the thing and get it surfaced. I use copper gaskets on my flathead motor projects...just sayin!
     
    Truck64 likes this.
  7. BigDogSS
    Joined: Jan 8, 2009
    Posts: 814

    BigDogSS
    Member
    from SoCal

    I think squirrel nailed it: Yes, Chevrolet did use locking tabs:[​IMG]

    Get REAL exhaust manifold bolts and the locking tabs shown above and be done with this issue.
    Of course, this is my opinion... :)
     
    Truck64 likes this.
  8. BigDogSS
    Joined: Jan 8, 2009
    Posts: 814

    BigDogSS
    Member
    from SoCal

    I just looked at the OP's original picture enlarged --> I was looking at the thumbnail size at first. --> that is a Y-block, correct? I thought we were talking about SBC ram horns. So, nevermind...
    I still I think you need to get better bolts and lock washers.
     
    Truck64 likes this.
  9. That heat shield has a crush rib around the ports, and that rib provided the seal and It looks new. Your used shields were probably pre crushed to fit the other engine and manifolds.

    It is a giant gasket that is a heat shield too. Used heat shield is a used gasket.
     
    Truck64 likes this.
  10. "Drug store bolts",,,
    Are they stretching?

    " crack the ears",,,
    Are the ears not setting flat? There is an air gap on some ears? You can see the ears move when tightening?
    That means something isn't flat.
     
    Truck64 likes this.
  11. Truck64
    Joined: Oct 18, 2015
    Posts: 3,854

    Truck64
    Member
    from Ioway

    Just means the bolts aren't anything special. All I meant by that is that I torqued them to spec hot and cold. Didn't want to gorilla torque 'em down trying to stop the leak and end up breaking something.
     
  12. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,459

    sunbeam
    Member

    A little high in the center is OK the ends will pull down low in the center they won't pull down I assume no problem with the other style manifolds?
     
  13. Truck64
    Joined: Oct 18, 2015
    Posts: 3,854

    Truck64
    Member
    from Ioway

    The stock manifolds (w/crossover) never had a problem, no.
     
  14. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,459

    sunbeam
    Member

    I guess that pretty much rules out the head side. I'd try the Yale muffler cement I've used it on FEs that I could no keep from leaking and it worked Just apply it to the gasket like any sealer and let it cure. If you get it at Napa don't let them give you the stuff from Walker.
     
    Truck64 likes this.
  15. Does your used heat shields have that raised crush rib around the ports and bolts?
    If they are used thet were crushed to fit the original engine and manifold mateing surfaces.
    Sorry it's not too clear I Cropped your photo
    image.jpeg
     
    Truck64 likes this.
  16. Truck64
    Joined: Oct 18, 2015
    Posts: 3,854

    Truck64
    Member
    from Ioway

    Yep, and I wondered about that. Figured maybe they would seal well enough if careful. Maybe not. I don't think anybody repops those shields either, like to use them. I'll try a few things and see what happens. Lots of good ideas to here! Much appreciated.
     
  17. Truck64
    Joined: Oct 18, 2015
    Posts: 3,854

    Truck64
    Member
    from Ioway

    They're pretty proud of that stuff! My NAPA had one tube left, $19.90 + tax. Thanks for the part #, the other stuff pops up in a search. It's 1 lb tube so should be good to go for a while.
     
  18. Blake 27
    Joined: Apr 10, 2016
    Posts: 555

    Blake 27

    Before I had my ram horns coated, I trued the gasket surface by gluing a strip of 80 grit sandpaper (longer than the manifold ) onto a large piece of plate glass. By rubbing it back and forth you will easily see the HPIM0206.JPG high and low spots. Keep sanding till the surfaces are completely trued. It actually sands pretty quick.
     
    Truck64 likes this.
  19. Truck64
    Joined: Oct 18, 2015
    Posts: 3,854

    Truck64
    Member
    from Ioway

    I knew I forgot something at NAPA today. A big enough piece of sandpaper! 80 grit you say? That's pretty stout stuff.
     
  20. HellsHotRods
    Joined: Jul 24, 2009
    Posts: 1,317

    HellsHotRods
    Member

    I agree, get some good copper Fel Pro that will crush seal
     
  21. So if gaskets are going to be used with the flatted heat shield- there ought to be a gasket on each side of heat shield.

    Head-gasket-heat shield-gasket-manifold.
     
  22. Truck64
    Joined: Oct 18, 2015
    Posts: 3,854

    Truck64
    Member
    from Ioway

    That sounds like it would be leak-city, not even workable?
     
  23. Well since the heat shield is supposed to pull double duty and be the gasket- but it cant, won't or isn't ,,, right?

    Where would the use of a single gasket go??? Between the head and heat shield allowing the heat shield to manifold go without ??? Or should the single gasket go between the manifold and heat shield allowing the head to heat shield go without ???

    That's my point-

    Which of the scenarios sounds less leak prone? Use of one gasket allowing the other surface to be without Any gasket? Or the use of a gasket sandwich utilizing 1 gasket on either side of the heat shield. Clearly using new heat shields that can still seal is the best option. If using gaskets Id guess it is much more leak prone for any one side of the shield to be with out a gasket, more than a gasket on either side which also sounds like a trip to leak city
     
    Last edited: Jun 11, 2017
    Truck64 likes this.
  24. Truck64
    Joined: Oct 18, 2015
    Posts: 3,854

    Truck64
    Member
    from Ioway

    OK... That's why you guys get paid the big bucks, to explain this stuff to guys like me.
     
  25. BJR
    Joined: Mar 11, 2005
    Posts: 5,994

    BJR
    Member

    I have used the top cast iron surface of my table saw and big sheets of sandpaper to true flat surfaces that are warped. Works great on large cast items.
     
    Truck64 likes this.
  26. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,459

    sunbeam
    Member

    Try the stuff you got from Napa use your heat shields apply it to both sides. The stuff truly sets up like cement filling up imperfections. I used it on a tractor manifold that had a place that was eroded and it stopped the leak.
     
    Truck64 likes this.
  27. Truck64
    Joined: Oct 18, 2015
    Posts: 3,854

    Truck64
    Member
    from Ioway

    That's the plan. Have some tree trimming to do this week sometime, not sure when exactly using truck to take away to the "yard waste site" with the old gal so it's gonna have to wait a bit. It needs to cure 24 hours or so right?
     
  28. HellsHotRods
    Joined: Jul 24, 2009
    Posts: 1,317

    HellsHotRods
    Member

    Get rid of the heat shield
     

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.