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leaky headers

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by Blazer-Boy, Jun 6, 2002.

  1. Blazer-Boy

    Blazer-Boy Registered Member

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    my 72 blazer is equiped with a rebuilt 350 engine that has less than 7,000 miles on it. when i bought it, it had an exhaust leak coming from the headers, where they bolt onto the engine. when i took the headers off, the gaskets were thrashed. i replaced them with Mr. Gasket's premium gaskets. this solved the problem...for about a week. now they sound the same, and it sounds like its just getting worse. they are hooker headers and they are pretty old, judging by the rust and and caked on dirt. is there anything i can do to salvage these? if not, what would be the best headers for the money?
     
  2. lukefalls

    lukefalls 1/2 ton status

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    Its hard to say the exact problem. I would start easy and cheap and then move on to more expensive items. I had the same problem that you're having with my Summit headers. I tried the preimum gaskets and they actually NEVER worked. I went to Kragen Auto and bought the basic FelPro gaskets and that solved the problem. Now if that doens't fix the problem for you, then the header flanges may be bent. If this is the case, it will be almost impossible to get it to seal. As for a replacement...I have the cheapy Summit headers and I am quite happy. I have not had exhaust leaks since the FelPro gaskets. If you spend big money on headers, you buy technology in tube demensions (i.e. equal length primaries or Try Y headres), not the sealing surface. I may be wrong about that though. Hopefully a new inexpensive gasket will work for you. Good Luck.
     
  3. chulisohombre

    chulisohombre 1/2 ton status

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    my headers had trouble sealing also.i went to national auto parts and picked up a set of the rol racing header gaskets.the header still leaked and i asked a friend of mine.he said to get anether set of the same gaskets and longer header bolts with lockwashers to keep it held down better.just put them on till you barely start to see the gasket crush.then run the engine to heat up the gasket and make them expand.then tighten the bolts the rest of the way.i havent had a exhaust leak yet.except what comes back in from the tailgate.seal replacement would probably fix that someday
     
  4. Racefreak

    Racefreak Registered Member

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    I'm thinking of doing these Summit Headers myself. They are the Ceramic Coated ones, supposedly made by Dynomax. Part #SUM-G9006-9
    I'm not sure I get the "for off road & racing use only" disclaimer. Should these be good? It won't let me post a link.


    Click to view image

    $174.39


    Overview
    --------------------------------------------------------------------------------
    Material Steel
    Finish Ceramic

    --------------------------------------------------------------------------------

    More power for less money

    Chevrolet/GMC: 1967-87 265-400, 1/2 ton, 3/4 ton, 1 ton truck, 2/4WD, 1 1/2 in. primary tubes, 3 in. collectors, ceramic coated, headers

    Our Summit performance headers are manufactured in the U.S.A. from heavy gauge .049 in. tubing for superior flow and greater horsepower. The headers feature a pressure-formed collector for better flow rate, 1/4 in. thick collector flanges with O-ring seal, and mandrel-bent, jig-welded tube-to-flange plate for perfect fit. Gaskets, mounting hardware, and reducers included. For off-road and racing use only.



    Sold as a kit.

    Specifications:
    * Primary tube diameter: 1 1/2 in.
    * Collector diameter: 3 in.
    * Finish: Ceramic coated
    * Will not fit angle plug heads.
    * Pre-1979 requires A/C bracket, BIG-10042
    * exhaust mount alternator requires, BIG-10031

    CHEVROLET K5 BLAZER 283 1969 -1991
    CHEVROLET K5 BLAZER 302 1969 -1991
    CHEVROLET K5 BLAZER 305 1969 -1991
    CHEVROLET K5 BLAZER 307 1969 -1991
    CHEVROLET K5 BLAZER 327 1969 -1991
    CHEVROLET K5 BLAZER 350 1969 -1991
    CHEVROLET K5 BLAZER 400 1969 -1991
     
  5. JoshA

    JoshA 1/2 ton status

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    I have hooker headers on my blazer and I had leaking problems as well. what solved it for me was gasket sealer. I can't remember the manufacturer, but they now make a gasket sealer for high temp (like exhaust manifolds). I believe it is called copper seal, it is copper in color anyway. you should be able to get it at any parts store.

    I bought the cheapest gasket they had (I'm broke /forums/images/icons/frown.gif ) put the gasket sealer on both sides of the gasket and I haven't had a problem since.
     
  6. Steve_Chin

    Steve_Chin 1/2 ton status

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    Forget any other header gasket than the Earl's Pressure Master gasket. It is hands-down the *best* header gasket. I don't use any locking garbage or anything on my ARP header bolts (other than anti-seize) and they don't back off and the gaskets don't leak. The gasket set is much more expensive than the garden variety stuff, but they are the best.

    Oh, FWIW, a friend was convinced that the SCE copper gaskets would fix his leaky header problems and he developed a leak about 6 months into the life of those gaskets. He took my advice to get the Earl's gaskets and he hasn't had a leak since (and has even had the headers off and on a few times without changing the gaskets).
     
  7. Blazer-Boy

    Blazer-Boy Registered Member

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    well...i think i'm gonna check out these ceramic headers from summit...along with some other brands of gaskets.
    those Earl gaskets sound like a miracle cure though.
     
  8. 70~K5

    70~K5 1/2 ton status

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    I had good luck with the OLD Mr Gasket header gaskets on my'69 Mustang. I never used anti sieze on the bolts they would lossen once or twice after bolting it all up but tighten them up and it'd save the gaskets. and after tightening them twice they'd stay tight till removed again. But then the ford didn't share the middle bolts like a SBC does. That's my biggest gripe with the design of the SBC.
     
  9. Racefreak

    Racefreak Registered Member

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    IF you buy those Summit Headers, you need the AC bracket. Summits' website is wrong. Pre 79 needs it, according to Flowtechs' tech line, as well as Summits' tech line. The bracket is a BLG10042. What's a little weird is Flowtechs' site says;
    4) Not legal for use on pollution controlled motor vehicles. Legal only for racing vehicles that will never be driven upon a highway. If you have any questions please contact your FLOWTECH dealer.

    32) Pre-70 vehicles with exhaust manifold mounted Alternator/Generator use bracket #10031.

    58) Will not fit angle plug heads.

    Now I'm a little confused! Do we need a bracket or not?
     
  10. lizard

    lizard 1/2 ton status

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    Ok Dont laugh (or go ahead, WTF) but I bought the complete exhaust system from JC Whitney mainly for the mandrel bent tubing. The headers that shipped were Hedman's IIRC and I used Felpro performance gaskets not the el cheapo ones that came with the headers. After 1 week the header bolts were loose and I tightened them up while the engins was still hot (warm). I did it again 2 months later. The collector gaskets were tightened once during installation. I have 8000 miles on it now and no leaks.

    I think the reason for the success was that I paid lots of attention to the alignment of the collector and exhaust pipe flanges, I have several hangers securly holding the exhaust system and I didn't over tighten the collector flanges (no flange distortion!!). Once the header was retorqued a couple of times the gasket seated fine.

    BTW: Was not happy with the JCW tubing - I had to do lots of customization to get it in the truck. Kinda worth it for the mandrel bends but I was expecting true bolt in and didn't get it. Of course this may be my fault because I ordered the headers one week and then the exhaust the next...
     
  11. chevyracing

    chevyracing 1/2 ton status

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    something else to consider on headers is the mounting surface of the header. Some headers have a flat surface like stock manifolds and some have the surface around the header port itself raised with a weld bead or something similar. I have had better luck with the raised bead type than the flat surface type as far as leaks are concerned.

    John
     
  12. BlazerGuy

    BlazerGuy 3/4 ton status

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    Actually the real expensive headers usually have a real thick mounting flange so it doesn't bend or warp....
     
  13. Racefreak

    Racefreak Registered Member

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    Someone's got the same damn headers I ordered from Summit in the 4 sale section here. They are asking $100, scratched but new. Flowtech. DAMN!
     
  14. 1HIHUM

    1HIHUM 1/2 ton status

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    i can't remember the brand, but I bought a set of aluminum gaskets for my headers as a last resort, before hurling them through my windshield. I could never get them to seal for more than a couple of weeks until I put these babies on. They are like 3-4 layers of aluminum sanwiched together. they have stayed leak free for 2 years now.They cost me around $40 but they were well worth it!
     

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