I usually use grey permatex (with a gasket) and red permatex (w/o gasket). Old timers swear by the shellac (indian head- also by permatex) My old flathead was 100% leak free (except for the popped freezeplug) and upon disassembly I see it was all done with gasket shellac. Anyone have any pro/con or rules for use for shellac? Its cheap 2.49, stickey as hell, and you don't get the colored rubber oozing out of your mating surfaces (personally I think that looks kinda trashy) so Im kinda thinking about going all shellac. Anybody know a reason not to?
The best shit in the world is Yamabond, sold at Yamaha dealers, it works better than anything I've ever used, 'spensive but worth it. I like Indian Head too, but this shit's the shit.
Best thread I've seen on the matter. Personally I am a big fan of the shellac over the RTV. http://www.jalopyjournal.com/forum/showthread.php?t=247570&highlight=gasket+sealer
Cork gaskets are best used when fresh. We typically glue the gaskets to the tins with rubber cement and leave the otherside of the cork dry. Gaskets need to be compressed slightly to work. Any kind of silicone or RTV is going to allow the gasket to squirm out of position before it gets properly crushed. Covers, tins and pans all need to be pre-fitted and fit correctly before you assemble them. No Permatex anywhere except the inner corners of many oil pans and the ends of the intake manifold. Nothing says 'hammer mechanic' more than colored ooze coming out from under valve covers, fuel pump bosses and water pump flanges. That being said, there is a time and place for everthing. The crutch.....errr RTV is useful if you have pitted or slightly damaged sealing surfaces you can't fix (like around water passage ports on heads and intakes - although we'll blast the area, epoxy the pits/damage then refinish the surface instead of using silicone) and is quite nice to have for road side repairs. I vote for the shellac/rubber cement over RTV/Silicone any day. -Bigchief.
The shellac lost popularity to "Gorilla snot" for holding gaskets in place. I was always told that gaskets make the seal. Cement holds them in place during assembly. Gorilla snot (3M trim adhesive) works for me. I use the black stuff for aesthetics. Without a gasket, silicone takes up the gaps. I always thought it was stupid to use silicone with a gasket. "Blue Goo" squeezing out of gaskets was a sure sign of a hack mechanic. JMO
If you must use sillycone, Permatex's "right stuff" is the best I've found and is remarkably close to Gm's own, that they insist on when replacing intake gaskets and such, however they won't say it's the same thing. Use it sparingly, globs of it squished out the side of mating surfaces is just plain wrong.
I agree with the purpose of the sealer or adhesive. I have used numerous permatex products, with only a few that work well. I use Permatex HI TACK for oil pan and transmission pan gaskets, and only use it on the block or transmission to hold the gasket in place. I do not use any of it on the pan side. On valve covers, I use Permatex weatherstrip adhesive and only put it on the gasket and valve cover. No adhesive goes on the other side of gasket or heads. The other product I use is form a gasket #1 for fuel line fittings. Does a good job of sealing. On copper head gaskets I use coppercoat spray. Never have tried shellac. RTV for gasketless surfaces and between rear main cap and block where the two halves of the rear main seal come together. Hydramatic flywheel to crankshaft: PLIOBOND. The Yamaha stuff sounds like it will work well too. I used to use GASKA-CINCH for motorcycle cases.
If you need to use silicone, gray is the color you want. I worked at a Honda store, their sealer, Hondabond, is remarkable similar to parts store gray RTV, even smells the same. Now at a Chrysler store and their gear/engine RTV seems to be the same stuff in different packaging. Maybe these OEM guys have it figured out when it comes to sealer, gray seems to be their favorite. Best advice is to follow the directions on the tube before you squeeze all the goo out and have to unroll it to read 'em!
You can read my posts on this subject. I don't think RTV has any place in gasket-sealed surfaces (except in an emergency road-side repair). It is a band-aid for poor assembly techniques. I rarely use anything other than plain old grease to seal most gaskets. For cork, I'm a fan of contact cementing them to one side & greasing the other. For water, I think it's OK to use a very, very thin skim of RTV if you can't get it to seal with grease due to pitting or something like that. RTV is the devil's work...I don't care what the OEMs use it for (they use it because it's cheap, not because it's better)
I have to agree with nads with the yamabond.Another co makes it if you dont want to get it from yamaha.Three bond sells it allong with some other quality sealents.Hylomar in the right place works well also.There is some real good sealig tech out there,the biggest fault i have seen is people missuse the product for its orig intention.Read the tube or can before oozing it out.
i have seen engines that where death by silicone, it oozes out and gets into the oil and plugs the oil pickup screen, starving the engine for oil...i guess its how you use it.
How do you clean up parts that have had shellac applied to them? That stuff is really gummy. Will carb cleaner or Brakleen cut it?
Laquer thinner cleans up the shellac very well. I agree about the no silicone to a point. If you use the proper end gaskets for a Ford intake, it will almost always leak. I use a bead of silicone for the end gaskets, but if it oozes out, I take the time to trim it and make it look right. I have found the Stihl uses a light grey sealer in place of many gaskets on thier 2 cycle equipment, I have never used Yamabond, but the stuff from Stihl is Awesome. It is a little pricey, so you will be more likely to use it sparingly.
Then you're doing it wrong. I've never used RTV on end gaskets on any of my Fords & never had them leak. I use the supplied cork gaskets too. You need to stick the cork to the block with something - I like Permatex #2. Then grease the top of the cork. This allows the cork to expand & move along the intake surface without grabbing & pulling. The permatex keeps the gasket from squeezing out. 30+ years building Fords of all flavors - never an intake leak. How do you trim the crap that oozes out inside your intake? You can't - those little dingleberries can and will break off & plug oil passages. RTV will degrade when exposed to oil. For some "oil resistant" types (notice they don't say "oil proof"), it takes a long time, but it does. Drop some RTV in gasoline & watch how it jellies up - the same thing happens when RTV is exposed to any petroleum product, including oil, it just takes longer based on the volatility of the petroleum product in question...
RTV is the devil, it's only good for repairing hobo shoes, and even then it's pretty worthless. PS, I'm fucking sick of sanding this Capri of mine.
The end intake gaskets for my 460 were rubber and when I dry fit the manifold it didn't look like they were even making contact. I (for the first time in my life) used NO gasket but put two beads of RTV, allowed them to skim over, then installed the manifold. There was no "ooze" to trim. The 460 is in my old motorhome and there is no way I wanted to fuck with leaks after it was all put back together. Aside from that I've always used indian head with 100% success.
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