Head gasket sealant

Discussion in '40- & 55-Series Tech' started by IdahoDoug, Nov 9, 2005.

  1. IdahoDoug

    IdahoDoug

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    I'll be putting the head back on my 80 tomorrow, and am thinking of using a head gasket sealant just for insurance. The head's flat, the block's flat but there is a slight texture here and there on the block sealing surface from the old gasket after cleaning. The machine shop doing the head work (cracked head) tells me that a quality anaerobic sealant such as "Gasket Cinch" or NAPA's house brand is excellent, but they would not use anything else such as "The Right Stuff" which is silicone base. They say it won't harm anything and can only help longevity.

    They tell me there is no need, but I'd like to use something as assurance. What do you guys think? What would you use? I'm using a factory Toyota gasket - metal laminate with a clear slightly gummy layer that actually contacts the head/block sealing surfaces.

    DougM
     
  2. CruisinGA

    CruisinGA

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    I'd listen to the man...


    Seems like the kind of guy I would trust in these matters...

    :cheers:
     
  3. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

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    Glorified contact cement....


    Stuff works great to hold a gasket in place.
     
  4. Rich

    Rich

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    When you say that the Toyota head gasket has a clear, slightly gummy layer that makes me think the factory has already got you covered. That's what I think, which in this case, is more than I know. Has the head man seen your gasket? And are you going to post a pic of the repair job?
     
  5. IdahoDoug

    IdahoDoug

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    Rich,

    Yeah, the clear layer seems to have adhered to the block a bit as well. Seems like it's supposed to heat cure and grip. But I'm looking for a bit of insurance, and if it won't negatively impact things it is something I"ll consider applying.

    Yeah, I'll take a pic of the repaired area tomorrow (Th) before installing it.

    DougM
     
  6. Rice

    Rice

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    The chances of an added sealant creating a high spot in on your sealing surface are pretty significant. If there is any residual material on the block and head get it off and get the metal dead clean, then use the head gasget only.
     
  7. brian

    brian SILVER Star

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    nothing you put in there is going to make the gasket last longer than it would on it's own. high temp and high pressure, the oem replacment gasket has you covered.
     
  8. honk

    honk

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    Yep, the risks are too high and the benefit questionable at best.

    You want assurances so you add doubts. Does that make sense to you, Doug?
     
  9. 4rnr

    4rnr

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    Good luck my buddy cracked the head on his 2F and im putting it back togeather now (thanks to Gumby's head) Now I just need to con some people into comin over and physically putting this monster back on!!
     
  10. krzyabncanuck

    krzyabncanuck USFS HOTSHOT

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    On chevy V-8's i use regular paint on the block before i put the gasket on. I learned this from an old man and i have done over 50 of them and never had one return, infact have done it to the shop truck about 15 years ago and no problems.

    On Toyota's i just use a Oem gasket though.

    HTH
     
  11. HawkDriver

    HawkDriver

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    I do mine clean.

    Did they come from the factory with sealant? No...
     
  12. IdahoDoug

    IdahoDoug

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    I understand the logic of using just the gasket - it's the way the engine came. But when I checked my block's flatness there's a measurable deviation using a gigantic guage that spans the entire block. It's minor. It's easily within tolerance and every 80 engine, indeed every production engine out there has deviations. But it's there and I know that using a product like this will provide more even pressure across the entire gasket than without it.

    I can't see it adding high spots because it goes on as a viscous fluid that will easily flow under the pressure of a head's clamping force. This isn't a product that goes on and dries, then is finished flat before applying the gasket. I saw those and would be concerned about that issue. It is also the good stuff that is anaerobic so it will cure in the absence of air.

    By providing more even pressure, it helps the head, gasket, and block behave more as one unit. Without it, the block will have greater clamping pressure at the front and rear and the block's measurable lower center (no "spot", but more an even curve) surface will have less pressure. What does this mean? Dunno. Would the new gasket I'm installing last 250,000 miles without the adhesive and 400,000 with it? Dunno.

    I'm not the slightest concerned about the block being acceptably flat - this is well within tolerance but once you measure it your mind won't put it away. The head has also been measured by a pro and it's extremely flat. I just want this work to last as long as is possible and there's considerable evidence a quality sealant will help. I don't see a downside.

    If one of you had cited some work where a sealant was used and it failed or reacted chemically with the gasket, etc - done. Not going to use it.

    Another consideration is that the block surface does have some very minor surface imperfections uniformly on its surface. These are the faint impressions of the 'tits' on the metal component of the original factory gasket that apparently are designed to grip the head and block. Over time, the movement of the head/block caused these tits to make faint impressions that fairly heavy sanding took most out. But they're still faintly there and I'm not going to pull the block and invest another $300 in having the block decked (not to mention the work to pull and reinstall it) over something that's normal. These marks are normal and I'm told the new gasket sealing material will handle it no problem.

    When the engine was built at the factory they weren't there and so the gasket was more than adequate. So now that these imperfections are there, is the factory gasket less than adequate and is it common in the 'replace a head gasket on an engine with 140,000' way of thinking that the engine will need a rebuild anyhow when the gasket fails earlier due to this normal aspect of block wear/aging? Maybe that's a good way of looking at it on a domestic V8, but on a Cruiser the engine STILL won't need a rebuild at 300,000 (I know several untouched 80 engines over 300k). On this one, I can still see the undisturbed pattern of cross hatching on the cylinder walls from when it was built. So, if I can assist the sealing and have the gasket last until the engine's got 400k on it or more, why not?

    I'm starting to get very long winded on this, but I don't see a downside. The race shop says it helps sealing and there's no downside. They don't use it on their engines because they strictly deal in brand new open checkbook stuff that's going to be used at max HP. You can't get in the door to buy an engine unless you've got a check for about $30,000. But the owner says he'd definitely use it for an ordinary engine being fitted with a new head gasket. He nodded his head more vigorously when I told him we tow heavy and there are times I'm going to be at wide open throttle for up to 3 minutes. So based upon all that new information what do you guys think? Gimme a downside here.

    Thanks,

    DougM
     
  13. honk

    honk

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    I think that you have a habit of thinking yourself crazy.

    By all means, Doug, USE THE STUFF!! Your engine WILL fail without it.

    If you don't use it you'll continually suspect that there must be a problem and you will pester yourself with it until you manage to convince yourself that you smell coolant out your tailpipe (if not out your own) again and will then remove the head all over again, probably managing to crack something else in the process.

    (The paragraph above, which begins "If you don't use it", applies equally if you do use it.)

    Now go back to the 80 forum where you and this sort of niggling belongs.
     
  14. IdahoDoug

    IdahoDoug

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    Honk,

    Why I oughtta...(Jackie Gleason in a boxing pose)....

    Yeah, there is that tendancy by my alternate personality. Just that I really whale on my rigs in summer when we tow and it happens that this one is the one we'll be using from now on since it's got air bags. I appreciate the abuse - I really do.

    I'm not as worried about having a problem and feeling the urge to tear it down again (gets old fast in a cold garage), as I am about buttoning this thing up with as many advantages to durability as I can provide so I can continue using it hard.

    So, now that I've talked you into agreeing with my POV, I'll feel better about doing what I want to do - use the stuff. Heh....

    DougM
     
  15. honk

    honk

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    Heat the garage, Doug.
     
  16. fcgadget

    fcgadget

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    I have been asking gasket questions everywhere lately. One of the consistent replies from the old time on-the-job mechanics runs like this:
    -Use the factory suggested/supplied gasket
    -don't add silicone
    -to stick it in place just run a light film of grease on it. This 'sticks'it and makes it a little easier
    to get it off next time.
     
  17. IdahoDoug

    IdahoDoug

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    Heated garages are for wimps... Bring a thermos of coffee out, and finish up as soon as possible.


    DougM
     
  18. VTFJ40

    VTFJ40

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    Depending on the "thickness" of the sealant, unless you can get a consistant even amount everywhere on the block and/or head, I think it will cause more problems than help.

    Do what you want, but I'd do it dry.
     
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