teflon coatings

lyonsy

Well-known member
hey
what is possible to have teflon coated i herd bores can be done as well but whouldent sealing be a big isue?
also does anyone do tflon coatings for 250 pistons i think acl may with the 4l au/ba pistons.
drift
 
Mant years ago there was an outfit offering 2-stroke motorcycle pistons with Teflon coated skirts.

Much more common are moly-disulfide coatings, sprayed on and heat-cured. The best ones are done by specialists like Swain-Tech. But in the heyday of 2-stroke motorcycle roadracing, a lot of amateur tuners did their own moly-coating with supplies from Kal-Gard. I did pistons, rotary-valve cases, aluminum bearing cages, Bing and Amal carburetor slides, possibly other things. Very carefully clean and prep the parts, spray on the moly with an airbrush, let flash-dry, bake at 300F for an hour. You can build up the skirts as much as .004", which lets you save old pistons (I had them knurled first). The coating will quickly get half-a-thousandth burnished off, but will then last a long time. You could do the pistons (easy) or the bores (difficult), but not both. Some guys coated plain bearings, but I only tried this on one antique outboard.

Google KG Industries.
 
I'm still thinking of having coated my lifters, the camshaft, timing set and oil pump internals.

I have been advised that coated pistons on a race motor that will be torn down and rebuild completely after a number of runs are the way to go, but may have certain disadvantage on street engines that are simply built to last.
the machine turned grooves on the piston skirts hold oil well; coating will fill the tiny grooves and make it much harder for oil to stick there.

While the coating would still take care of the dry lubrication of the skirts to a point, it can't help heat dissipation like oil does.

I'm still thinking about a solution to have a friction-reducing coating, but keeping the turned grooves intact. Maybe both can be accomplished by a partial coating on the skirt outlines, leaving the center part of the skirts bare.
 
Kal-Gard claimed the product improved heat dissipation, and even had a coating which you sprayed on air-cooled heads and cylinders to improve heat transfer. I never tried it. I understand your thinking, which is that the heat transfer from aluminum piston to oil to iron cylinder wall may be impeded, not abetted, by a moly coating. I don't know. All I know is that it worked well on 2-stroke race motors, and didn't seem to cause any more seizures than usual. If used to build up used pistons to restore the correct clearance, it would prevent seizures. I can't say for a fact that the coated surface "wets" (holds oil) any better or worse than bare aluminum.
 
hey
ok now here's a problem i cant buy 35thou piston's and if i coat them and bore it out a little extra the pistons around the ring lands ant tight losing comp along with the rings.
how do you get around that as all the pistons i have are broken.
also whould it be possible to coat cams and lifters and valve's (stems) in this stuff and not have it fall off?
drift
 
Hate to give you a hard time, Drift, but you need to read your posts out loud to see that they make sense, and fix the spelling and grammar before you enter them. I can't figure out what you're saying; sounds like you want to coat broken pistons . . . .
 
speeling no can help generaly to tired to do a spelling and gramer check.
when you coat a piston you coat the skirt
since all my old pistons that will have wear are broken i cant use them.
i cant buy a 40thou piston with a 35 thou skirt to be built up.
maching down the skirt on a piston to 35 thou is going to be expansive so proply cheaper to do the bore's instead.
also does is have a habit of breaking off as ive seen and herd bad story's about coating's in combustion chambers and flaking off and taking pistons nd rings with it.
so whould it be suitable to use with cams lifter's (together or must be seperate) and valve stems.
sorry if it dident make sense just trying to keep it short
drift
 
Hmmm, well I'll take a stab at it.

The stories you've heard about coatings flaking off and wrecking pistons are not the skirt-coatings I was talking about. Racers and others who are willing to spend a lot of money for max performance are getting the tops of the pistons ceramic-coated as a heat barrier. Some of these coatings are better than others, but detonation can break bits of ceramic off even a good coating, and ceramic will gouge aluminum something awful.

The moly-coatings on pistons are very reliable if done right, and several piston companys will now sell you brand new pistons that are already coated. Home-shop coating depends on how meticulously you clean the parts and apply the coating.

I can't answer your particular dilemma.
 
yep thats what i seen and herd with the cermaic coatings
so there hasent been any troble really with molly coatings on pistons
what about with cams lifters and valve stems
drift
 
I know at least one shop was doing valve stems for a while in the '60s. How it worked, or whether it is done now, I don't know. Google Swain-Tech.

There are other surface treatments of camshafts (not coatings), such as Parkerizing. Also, any good modern oil has additives that stick to the cam to protect it from a dry start; you can feel it by rubbing your thumb on a cam when you pull it out of a motor. A new addition to the market is the ceramic-base lifter. These have very low friction against the cam lobe, so low-drag and very low wear, and they have no moving parts, an advantage over roller-tappets.

Also, if wear-reduction is your aim, install an electric engine-heater that you plug in at night. These are commonly used in cold winter conditions, but have numerous advantages in almost any climate. If Detroit wanted to build cars that last a lot longer than the warranty, they would have engine-heaters built in.

That's all I've got to say to you, Drift, and I'm getting myself de-listed from this thread. I can't even figure out some of your stuff, and even when I can, I don't like your attitude. You're either too lazy to edit yourself, or you think there's something cute about writing like an immigrant fresh off the boat. It shows a basic disrespect for the rest of us.
 
Okay, Y'all, since my last post, Drift sent me a friendly P-M appologizing for not being more readable. And I expected he would flame me and that would be the end of it!! Now I feel bad about getting on his case!

I had a boyhood friend who had a terrible time in school, and people assumed maybe he was just dumb that way. Turns out he had dyslexia, which was very little understood at that time, and his brain was hard-wired a little differently than mine. The sad thing is that he had internalized the assumption that he was dumb, and that made his problems worse, but in fact he was an inherently bright, creative guy.

Drift didn't say anything about dyslexia, and from reading his message to me, I would say he doesn't make excuses for himself. Well, given my experience with my friend, I don't have an excuse for belaboring Drift in my last post!! At least I could have done it privately (which I didn't think of until later).

So, sorry about that, Drift!! I can see now that you are trying. If you don't mind me sometimes asking you to explain your posts in different words, we surely can communicate.

--Smitty
 
hey
thanks mate but you needent worry about offending me iam fairly easy going and dont take much to heart.
as i said i have the upmost respect for everyone here and will try harder in the futer? to be better understood and use less slang ive picked up which i tend to use a lot also.
its good to see there are still people who help others i try where i can but like you from what ive gatherd shake my head and say been there done that that way it wont work as well as this way.
but all you can do is advise and i thank you for it.
drift
 
drift cortina":2yc7phpg said:
hey
thanks mate but you needent worry about offending me iam fairly easy going and dont take much to heart.
as i said i have the upmost respect for everyone here and will try harder in the futer? to be better understood and use less slang ive picked up which i tend to use a lot also.
its good to see there are still people who help others i try where i can but like you from what ive gatherd shake my head and say been there done that that way it wont work as well as this way.
but all you can do is advise and i thank you for it.
drift

Google toolbar has spell check...makes it easier. I have to say, if a post isn't easy to read I tend to ignore it.
 
I had a chuckle here. Smitty is evidently a skilled machinist - he knew exactly how much heat to use, and where to apply it. :wink:

Well-phrased questions probably get better answers; it's that old thing of meeting people halfway - and they're more appealing when Googling for something.

Cheers, Adam.
 
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