Ceramic Coated Pistons?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
If I read that correctly, it sounds like we agree. You were doing great until the last sentence.
RACE ON!!!
Originally Posted by SWCDuke
Detonation increases the heat transfer rate to the boundaries by up to an order of magnitiude.
Duke
Duke
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,264
Don't know where you get your information, but if you read SAE papers over the years and other research on the physics of shock waves, that's the result. An order of magnitude is "times 10". It's not the mechanical pounding they take, but pistons and valves can fail in a detonation environment because the materials get hot enough to loose considerable mechanical strength. Most aluminum piston alloys loose strength rapidly at over 400F, and most valve materials are working within a 100 degrees of the point where material strength degrades rapidly, so it doesn't take much sustained detonation to cause failure.
Duke
Duke
Melting Slicks
Joined: Sep 2004
Posts: 3,153
Likes: 114
coatings are starting to get big over here in the UK. the theory definatly seams to work, especialy if you are running FI. they say you can run higher boost with less det, a very important thing for FI. also the theory would say that coatings would keep the heat where it should be thus reducing thernal stress and reducing the strain on the cooling system. there will allways be two sides to the argument though. some say "what if the stuff comes off" and this is a valid responce. but i think you have to way up the possiable down sides to the garanted plus points. also, over here at least, coat tech is improving all the time.
i personaly would def get the pistons done. i would also get the whole bottom end nittrided just to help out.
just my opinions but thats what we are here for.
thanks Chris.
i personaly would def get the pistons done. i would also get the whole bottom end nittrided just to help out.
just my opinions but thats what we are here for.
thanks Chris.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by SWCDuke
Don't know where you get your information, but if you read SAE papers over the years and other research on the physics of shock waves, that's the result. An order of magnitude is "times 10". It's not the mechanical pounding they take, but pistons and valves can fail in a detonation environment because the materials get hot enough to loose considerable mechanical strength. Most aluminum piston alloys loose strength rapidly at over 400F, and most valve materials are working within a 100 degrees of the point where material strength degrades rapidly, so it doesn't take much sustained detonation to cause failure.
Duke
Duke
RACE ON!!!
Melting Slicks
Joined: Mar 2002
Posts: 3,108
Likes: 126
From: S.L.C. UT
I am a firm beleiver in coatings. A couple years ago I tore my engine back down, and the only thing that I changed was doing coatings. I had HPC Coatings do the piston skirts with a dry film coating, the piston crowns with ceramic coatings. Then I had the chambers, valves, exhaust ports all ceramic coated, and did the valve stems with a dry film coating. I also did the valve springs while I was at it. When I got the car running again, I was amazed how much more fuel this thing wanted. I had to add 7% more fuel to the engine to get the A/F ratio back in line. It had to have picked up at least 25 hp. I never did dyno it, because a while later I made some other changes. But it was very noticable, and the engine requiring more fuel speaks for itself.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Homie
So by wanting more fuel does that mean it decreased gas mileage?
:RACE ON!!!
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,264
[QUOTE=CFI-EFI]Thanks for the, "times 10", explanation. If you had written, "by up to an order of magnitude of 10.", I would have "got it".
QUOTE]
Yes, "order of magnitude" is common engineering/scientific jargon meaning "times 10". Two orders of magnitude is 100 times, three is 1000, etc.
Duke
QUOTE]
Yes, "order of magnitude" is common engineering/scientific jargon meaning "times 10". Two orders of magnitude is 100 times, three is 1000, etc.
Duke
Burning Brakes
Joined: Aug 2001
Posts: 857
Likes: 0
From: York Pa.
I won't profess to know diddly about thermal dynamics and such, because I don't. The only issue I have is with using any type of moly coating in an engine. Moly and moisture do not mix at all. My experience with moly is limited to firearm barrels, but the same principles apply. Few of the top shooters are using it anymore. When moisture comes in contact with moly coated metal, it pits in a big darn hurry. Some shooters clean moly coated barrels between as few as ten shots, when they are going to fire a hundred or more in a day. I wouldn't be comfortable with an engine that was coated sitting all winter. Classic
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by SWCDuke
Originally Posted by CFI-EFI
Thanks for the, "times 10", explanation. If you had written, "by up to an order of magnitude of 10.", I would have "got it".
Duke
RACE ON!!!
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Classic63 - your talking about apples and oranges. I have a "Moly" barreled target rifle. that is short for "Chromemoly" it's a steel mixture that doesn't have near the ability of stainless steel to resist rust.
Moly coated piston skirts like mine are molendium (sp?) It's and additive to things like wheel bearing grease because of it's friction fighting ability.
I had my roller cam go while out road racing. I had nearly 20,000 bad street and track miles. The ceramic coating was covered in light carbon, but intact. My exhaust valves were nearly devoid of coating on the back and lower stem. I would attribute this to heat and erosion from hot gas roaring out the port. The chamber side face was probably 80%.
The chamber it's self was @95% intact. I did have a bad day with preignition once and it might have been damaged by this.
I had my crank nitrided and coated with oil repellant.
Moly coated piston skirts like mine are molendium (sp?) It's and additive to things like wheel bearing grease because of it's friction fighting ability.
I had my roller cam go while out road racing. I had nearly 20,000 bad street and track miles. The ceramic coating was covered in light carbon, but intact. My exhaust valves were nearly devoid of coating on the back and lower stem. I would attribute this to heat and erosion from hot gas roaring out the port. The chamber side face was probably 80%.
The chamber it's self was @95% intact. I did have a bad day with preignition once and it might have been damaged by this.
I had my crank nitrided and coated with oil repellant.
Burning Brakes
Joined: Aug 2001
Posts: 857
Likes: 0
From: York Pa.
gkull, I was talking about molybendium. It can be applied to bullets and barrels a few differnet ways. It was all the rage for awhile in the shooting world but has lost it's luster in a big way. I cannot say with definetive proof that moly is bad in an engine, because I have not tested it in that application. However, moly's tendence to draw moisture and the results of it coming in contact with moisture would make me shy away from it. Other than the moisture issue, moly is a great substance.Classic
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,264
Molybdenum is a basic element - a metal. The additive added to high temperature EP grease is molybdenum disulfide - MoS2. It's about as different from pure molybdenum as water is from it's consituent basic elements - hydrogen and oxygen.
"Moly" dry film coatings are based on MoS2, which is a solid. Piston skirt coatings are gaining popularity with OEs. GM began using "polymer" coated pistons on LS6 engines in late '01. The purpose was to run tighter clearance to reduce customer complaints of cold piston slap, and the polymer coatings allow the use of tighter clearances without increasing the chances of piston scuffing, so it really has nothing to do with "reducing friction".
Duke
"Moly" dry film coatings are based on MoS2, which is a solid. Piston skirt coatings are gaining popularity with OEs. GM began using "polymer" coated pistons on LS6 engines in late '01. The purpose was to run tighter clearance to reduce customer complaints of cold piston slap, and the polymer coatings allow the use of tighter clearances without increasing the chances of piston scuffing, so it really has nothing to do with "reducing friction".
Duke
Racer
Joined: Apr 2003
Posts: 286
Likes: 2
From: Suffolk VA
Hey guys sounds like we ventured away from the ceramic coating and jumped to the DFL coatings used on some hi-pro pistons. I think the orginal post wanted to know more about some of the TBC's that alot of the race teams have started using.
Here is a great site to check out if you are into coatings of this nature: http://www.cermakrome.com/
Here is a great site to check out if you are into coatings of this nature: http://www.cermakrome.com/
Pro
Joined: Jan 2004
Posts: 535
Likes: 1
From: Darwin, Australia NT
Quote off that website
"In fact certain thermal barrier coatings will move an engine into detonation"
Tech line coatings are also into Thermal Disperants, the exact opposite of Thermal Barrier Coatings.
"In fact certain thermal barrier coatings will move an engine into detonation"
Tech line coatings are also into Thermal Disperants, the exact opposite of Thermal Barrier Coatings.
