engine coatings
12-08-2006, 09:56 AM
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engine coatings
Does anyone use coatings, thermal barriers or anti friction coatings in their engines. I'm thinking about raising the compression ratio in my engines to 10.2 to 1 and I would use the coatings on valve faces, combustion chambers, piston tops to help control detonation. I trailer and fill up at gas stations so premium gas is not much of a problem. Does this stuff work? Will it increase hp by itself?
12-08-2006, 11:02 AM
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Re: engine coatings
Originally Posted by PatriYacht
Does anyone use coatings, thermal barriers or anti friction coatings in their engines. I'm thinking about raising the compression ratio in my engines to 10.2 to 1 and I would use the coatings on valve faces, combustion chambers, piston tops to help control detonation. I trailer and fill up at gas stations so premium gas is not much of a problem. Does this stuff work? Will it increase hp by itself?
Most seem to favor coatings, however I remember Raylar had something to say about them in my thread back then.
Originally Posted by Raylar
You might want to be careful with the ceramic top coat on the pistons with iron heads. Its been our expierence that the coating can raise the cylinder temperature in a big block iron head motor much higher than it will be in an aluminum head bbc motor. Your piston detonation point and damage is in the quench area not in the combustion chamber indicating you had possible pre-ignition in that area. You could be having a detonation issue with 34 to 36 degree timing and high cylinder temperatures with todays rot gut fuel. I would suggest not using the ceramic top coat in this motor. Just my opinion.
Ray @ Raylar
Ray @ Raylar
12-08-2006, 02:27 PM
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Re: engine coatings
Originally Posted by eliminatethis
i send all my coating work to calico coatings (bearings,pistons,heads inc. valves and pipes ) never a flaw
Here is some interesting reading that I came across while researching this project. http://www.popularhotrodding.com/tec...ion_ratio_tech
Last edited by PatriYacht; 12-08-2006 at 02:36 PM.
12-08-2006, 02:43 PM
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Re: engine coatings
Originally Posted by Wobble
I use Polydyne, piston top and side coatings, the motor torched a piston after 170 hours due to a vacuum plug on the carb base plate coming off. The other pistons were in very good shape.
Most seem to favor coatings, however I remember Raylar had something to say about them in my thread back then.
Most seem to favor coatings, however I remember Raylar had something to say about them in my thread back then.
Chamber cavities between the piston and the cylinder head between about .060-inch - .0120-inch appear most likely to be the site of detonation. Speeding up combustion mixture motion/agitation is vital. This means maximizing the quench action. On a small-block Chevy with a stock block height, a stock compression height piston is typically .025-inch down the bore. With a .040-inch gasket this makes the static quench clearance .065-inch, which is way too wide. By cutting the quench clearance the burn rate and quality improve to the point where the motor gains compression and is less likely to detonate even at the higher ratio involved.
So how closely can the pistons approach the head face? Although it comes under the heading of "don't do this at home" I have run the static piston/head clearance down to as little as .024-inch in a 350 with stock rods and close-fitting hypereutectic pistons. The pistons just kissed the head at about 7,000 rpm. As far as power is concerned, an associate of mine ran some tests in a nominally 450-horse 350 and found that each 10 thousandths of quench reduction was worth approximately 7hp.
12-08-2006, 04:03 PM
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Re: engine coatings
i mostly send them new heads or fresh heads they told me i could send them heads just cleaned up and apart i use calico from there reputation nothing but top notch there is a guy in your area that has a machine shop that has done a couple of blower eng. for a close freind of mine ron foster in waterford his name is scott carter 248-240-4265 used to work for wilson eng.
12-09-2006, 12:39 AM
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Re: engine coatings
Ian,when I upgraded my 540 2 years ago I sent my new afr heads and pistons to swain tech and had the valves,chambers,poston crowns and skirts coated. My old pistons had burn't oil on the bottom fro running slightly lean. I stuck with fairly tight clearences even though I'm running 10 psi of boost,I haven't torn motor down yet but I never stuck any pistons yet. I will give you a call when I tear the motor down and see how everything looks,Smitty
