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Discussion Starter · #1 ·
I bought a 0.38mm thick COPPER head gasket for my motor. I have never used one before; I always used the paper/metal/paper type with the metal ring around the bore part. Well, anyway, do I need to use any sort of sealant on the gasket? Silicone sealants always say on the tube not to use where it might contact gas and specifically say don't use it for head gaskets. The only reason I ask is that paper gaskets compress and shape themselves to seal between the head and cylinder deck, but I don't think a copper gasket will compress much at all. So basically, do I need sealer and if so what kind?



 

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arlindsay1992 said:
I bought a 0.38mm thick COPPER head gasket for my motor. I have never used one before; I always used the paper/metal/paper type with the metal ring around the bore part. Well, anyway, do I need to use any sort of sealant on the gasket? Silicone sealants always say on the tube not to use where it might contact gas and specifically say don't use it for head gaskets. The only reason I ask is that paper gaskets compress and shape themselves to seal between the head and cylinder deck, but I don't think a copper gasket will compress much at all. So basically, do I need sealer and if so what kind?







Use this...just let it tack up before u put it together



 

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I don't know if I'd use any kind of silicon sealer (rvt sealant, or yamabond or what not)



as I'm sure none of them types of sealants will be good enough to handle combustion temperatures or combustion pressures..
 

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Like stated above use the Copper Coat spray. Put a liberal coat on both sides let it tack up and slap it together. The stuff works great. I have been using it for years and have put a few engines together re using the gaskets with just a coat of it and never any problems.
 

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I don't use any sealant on my copper gasket motors. Make sure all surfaces are clean, no oil/etc, torque properly, retorque after the first heat cycle. On the 2nd, 3rd and 4th use of the gasket, I anneal it first. After that, it gets tossed.
 

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Discussion Starter · #9 ·
Well, I trust Kurlon being the outstanding engine builder guy but he is the only person opposing many others who suggest using the copper gasket stuff. So Kurlon, is there any real disadvantage or some reason not to use the copper stuff? I have to admit it does seem like a good idea. I'm leaning towards picking up some of that gasket stuff.
 

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I haven't used copper spray gasket before, so I can't comment on it directly. On copper head gaskets, if you're going to reuse them, you need to be able to clean them without working the metal any more than you have to. No bending, scraping or hard work with a scrubbie, etc. You then need to anneal it by heating it up till it just glows a dull red, which is not going to be pleasant if you're burning off old gasket compound.



I avoid gasket compounds in general if they weren't called for in in the design (Newer motors machined to better tolerances now use Yamabond and the like in place of gaskets for example.) to avoid throwing the tolerances off (gasket compound takes up space) and even more importantly, avoid little bits of it in my crankcases trying to clog an oil passage.



That said, I know many who do use gasket compounds without issue. TB even calls for it with their 60mm skirtless bore kit for Jialing style 125 motors. If you're not planning on taking that top end off any time soon, and understand that if you do, you'll need a new gasket, cote it up and and report back how it works.



Also, because the gasket is thinner than a stock gasket, you can't use the metal washer/spacer with the o-ring that goes between the head and cylinder to seal the oil return passage. You might not be able to use the o-ring either. It may be too thick and cause an oil leak by preventing the head from sealing on the bottom. I've been using thinner green units from Ducati's parts bin, or you could have someone flycut the recess on the cylinder face to make up for the reduced gasket thickness?
 

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We used copper gaskets without spray sealer on 1400hp 632" nitrous engines, with just silicone around the water passages.



Like Kurley said, just anneal and reuse. My RD400 got the gaskets cooked on the gas stove and re-ran a few times, when it would stick a piston. No biggie.



I do use a light coat on steel stock gaskets when reusing them, but just because they aren't made to reuse.
 

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Discussion Starter · #12 ·
Thanks for all the info guys. I think I'll end up not using any sort of sealant. Kurlon's explanation made pretty good sense. I think I'll look through my ziplock of o-rings and seals and see if I can find an oil return o-ring that is softer than the other ones so it will squish better, and I'll use a bit of silicone around the oil passages only. Thanks for the advise everybody.
 
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