Head Gasket Tips - Road Star Warrior Forum : Yamaha Star Warrior Forums

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Old 05-24-2007, 08:20 PM   #1 (permalink)
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Default Head Gasket Tips

Just wanted to share with you my experience with head gaskets. As most of you know, I've been racing my Warrior with up to 100 horsepower of nitrous added to the 95 horse engine combo. In my earlier life, I spent a lot of time in automotive racing applications, both as a builder and as tech support through my old oil company's racing efforts. To make a long story short, I'm running the same head gaskets after three teardowns with absolutely no leakage or other problems. Here's how....

Use only tri metal type gaskets. I use the Yamaha ones. I believe the oversize Cometic gaskets are also tri metal. The tri-metal gaskets act like a kind of spring and cushion combo, so they are constantly "adjusting" to expansion, contraction, etc. The best method I've found to achieve successful sealing, especially after many reinstalls(not only with these, but also all the other metal gaskets) is to:

1. Clean head and cylinder mating surfaces thoroughly with acetone and a grey scotchbrite pad. Use acetone and white paper towel before final assembly. Don't be lazy, remove the locating dowels to make sure you can clean the whole mating surface. Re-install dowels using non-hardening sealer lightly to insure they'll stay in position when dissasembled later. Don't overdo it and goop it on the surfaces. These need to be spotless and dry.
2. Regardless whether gaskets are new or used, wipe them down with acetone and then, give them about three coats of Rust-O-Leum barbecue paint. Let them dry for around an hour. The following cleaning and assembly steps should give them enough time. What the paint does is heat set after the engine warms up. This increases the sealing capabilities of the gaskets and prevents blowout. This is particularly important if the engine is detonating. One of the areas particularly sensitive to detonation erosion is the interface at the initial quench area and cylinder. Detonation chisels at the gasket here and can eventually burn through causing leaks.
3. Clean studs and nuts, washers THOROUGHLY. Rinse with acetone or brake cleaner. Lubricate only the nut flanges and washers before assembly. I even go so far as to use Permatex or equivalent red engine assembly lube under the nut flanges and washers. This prveents microwelding and insures smooth torque/stretch of the fastener. Don't lubricate the nut threads themselves, instead, dribble a little engine oil on the cylinder studs before assembling the gasket and cylinder head. This prevents oil seeping onto the gasket from the nuts when they are turned over to install. If you find a loose stud, unthread it, clean the threads and re-install FINGER tight with red loctite. This is mainly to prevent it from coming partially loose during teardowns, but also provides some additional oil sealing capabilities.
4. Install the gasket and head carefully. Make sure it is going on smoothly and correctly. Tap gently around the head with a block of wood or rubber mallet until the head is fairly flush with the cylinder and gasket. Try not to be tempted into using the nuts to pull the head down if it doesnt seem to mate. What could be happening is that the head is somewhat cocked and/or one of the dowel holes has some crud. Either way, forcing the head down with the nuts will cause it to warp and at the very least, cause a minor leak. Worst, major blowby, oil leaks, and possible cracking. Remember, the cylinder studs clamping force also maintains the geometry and alignment of crankcase, cylinder barrel, and cylinder head. Get the picture? Take your time before assembling the components to clean, and also to practice dry fitting them before commiting to the gasket and oiling process.

5. Finally, install the bolts finger tight. Torque them in many stages. I use 4. Divide the total torque by 4 and approximate each step. For instance, the center small studs are torqued to 28. I start at seven, then 14, 21, and finally 28. Same with the outers. I torque them starting at 11, then 22, 33, 43. Remember that the order of removal and installation of the nuts is critical to prevent warping and insure equal clamping force on the head. Make sure that you get the pattern from a manual. If you don't have access, someone on this site, including me can get it for you.

That's it. This is what works for me. Oh, and one final thing, I'm not so cheap that I won't buy gaskets. Since I'm racing, I often have to tear down and rebuild the top of the engine regularly. Mainly, because with all the retarded timing and nitrous, I tend to stick the exhaust valves. Unfortunately, my Yamaha dealer does not adhere to the strict schedule I do. I'm lucky if he has ANY parts I need, especially in emergency. I reused them out of necessity, crossing my fingers and praying, and it worked out. Now I do it just to save me time, and to see how long I can really push it.

Hope this helps. Even if you're not trying to reuse gaskets, the above procedure will guarantee success.

Let me know if you have any questions.

Sam Vallas
Orange City, FL
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Old 05-25-2007, 02:15 PM   #2 (permalink)
 
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Default Re: Head Gasket Tips

Man, that is an awesome description. Thanks so much for the detailed tips!
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Old 05-25-2007, 02:58 PM   #3 (permalink)
 
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Default Re: Head Gasket Tips

I will have to try the option 2 sometime. Usually have been using the copper gasket spray.

Good points!
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Old 05-25-2007, 05:07 PM   #4 (permalink)
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Default Re: Head Gasket Tips

I just gotta ask, Rustoleum BBQ Paint????? How did you ever come up with that?
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Old 05-28-2007, 10:13 AM   #5 (permalink)
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Default Re: Head Gasket Tips

I have been using it on my exhaust system for quite awhile. I noticed that it seemed to set up really nicely when heat cycled. I tried using it on various less critical gaskets. Again, my stealer never stocks any of these consumables, so I was forced to reuse them. The paint seemed to mimic the factory coating perfectly in handling imperfections, so I expanded its use to the other gaskets, including head gaskets. Believe me, if anybody should have been blowing head gaskets, I should have. Until I got the nitrous dialed in, I was getting some excursions that should have blown them out like tissue paper, but no problem. Remember that in the old days when they used copper gaskets, they always painted them with aluminum paint before reusing them. The copper is not a stretch. I just think that the BBQ paint, besides looking cool on the pipes and other hot parts, seems to set up and seal better at high temperature (obviously) Remember, though, it's important to make sure that all the old paint is removed from the headgaskets before cleaning thoroughly, repainting and reinstalling. The other gaskets only need a wipedown with acetone and repaint and you're good to go.

Sam
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