Dumb question...

Where's the friction? I thought it was just the rings that came in contact with the cylinder walls...

 

Ya most of the friction comes from ring drag. The pistons also add a significant amount of friction the cylinder walls. Also, bearings add friction.

Most friction coatings are molybednum based, the stuff that the popular 'moly' rings use. This reduces friction between the rings and the cylinder walls. To further reduce this friction, coating the piston skirts with this anit-friction coating will help.

Reducing ring thickness and oil ring tension to reduce friciton, should only be used by serious drag racers. And reducing ring thickness is a risky thing when using large amount of nitrous or in forced induction apps. Using low tension oil rings on the street will reduce friction, yes, but unless you are running either a dry sump system or vacum pump to help reduce oil blowby into the combustion chamber. Most street cars dont have these so I wouldn't put low tension oil rings on them, but to each his own. If you can handle some extra oil cunsumpsion then go for.

But try the thing rings on the street, if they work, then sweet.
Always try new things.

Hunter

 

Thanks. I always thought the rings kept the piston itself from making contact with the cylinder wall.

 

I don't do a blown motor without the barrier coating anymore. Once the benefits were explained to me by Scott at SD Concept Engineering and how much boost and compression I could run SAFELY with the coatings I gave it a try. 9.7:1 (Scott wanted me to run 10:1 but I chickened out!) EFI 468 big block, 14 psi of boost on 91 octane with no intercooler, no detonation even at 28 degrees of timing (most I tried). No way that would have lived without the coatings. To me $300 is not expensive for the enormous safety factor it gives. And not having to take all the timing out of the motor makes a big difference in power.

I've used Swain and Techline, both have worked flawlessly.

Jody

 

I was curious about this.. I sent my intake manifold to be coated top and bottom but after reading this article should I coat it with a thermal barrier on the top?

http://www.techlinecoatings.com/art...old_Article.htm

It says that you want a thermal barrier on the bottom and a thermal dispersant on the top for the air to cool down faster the intake manifold..

WHat you guys think?

 

You only want to use a barrier on the bottom b/c any heat that does get into the intake you want to pull out. The ambient temp under the hood is not enough to put a barrier on. The dispersant will pull the heat alot better than trying to block it. Plus any heat that would get in the intake couldn't get out. Another advantage to Techline coatings is that the thermal barrier has oil shedding properties as well. So any hot oil from the valley will not stick to the bottom and absorb the heat. In addition to what everyone else has said about coating the entire engine is well worth the $. The differences in the tune that you can run can result in big gains. And the friction that is cut down by coating the bearings as well as the CYC walls is awesome. The differnce you can feel just by touch is very noticable.

 

Swain offers two different coatings, one for the bottom of the intake (a thermal barrier) and one for the top which is an emitter.

"Intake Manifolds. Black body emitter on top and TBC on bottom maintains the mixture's temperature at the optimum for the desired performance characteristics."

http://www.swaintech.com/autolc.html

Rich Krause

 

Sounds to me like the ring might be the wrong setup. Which JE lightweight piston? Was the motor running anything other than NA? Alot of this will have to do with it.

BTW a low tension setup can work on a street car BUT IT HAS TO BE DONE RIGHT! In total it can be worth 2-3% average power, which is alot to get a constant jump across the RPM range. That's almost like free cubes. There are a few ways to get crankcase pressure down in a street motor w/out a vaccum pump and w/o a dry sump. Cylinder wall finish needs to be good also. Only good way to check that is with the right equipment. Piston rings are very important in a engine. I work with companies that other people do not like (i.e. Total Seal) and I like what they do and how they work with people. Funny thing is there are alot of other really high end people that do too. Gaerte, Automotive Specialists (both big in the circle track ranks) Joe Gibbs, F1, WRC just to name a few others. Piston ring science is some interesting ****. How much should you play with it on a street car? On the sealing side alot. On the friction side? some. I would play more with the right oil rings, put the top ring in the right spot on the piston and make sure that the crankcase is not running extra high pressure.

Skirts also make alot of friction, not as much as the rings do. One more reason a long rod is good is because it adds piston stability, which means smaller shorter skirts. Piston design is also a little area to find some interesting things in.

One of the things that makes a $40K engine that vs a $6K engine is the little things. Custom pistons, custom rings, custom, custom, custom. Going into the details is a big thing in terms of the most bang you can get, but that costs mucho money.


Highlander, On a $6000+ intake manifold I would do the TBC and heat dispersing coating too. TBC on the bottom and HDC on the top. You wonder what a $6K+ manfiold consists off? About 120+hours of work. Just ask Wilson Manifolds. I don't know how much it's worth, but it can't hurt at that price level. Something like a air gap intake is probably going to do more for you. Keeping the engine running is also one way to keep it cool by constantly moving air thru the runners, that will easily take about 30+ degs out of the intake.

Bret

 

And all that heat going to the pistons...

 

Nope. The heat emitted from the top of the manifold is heat lost from the intake charge, which is a good thing. The heat rejected by the TBC is prevented reaching the intake charge. It is retained in oil and to a letter extend in the block, both of which are preferable to the intake charge.

Rich Krause

 

I know the heat emmited from the top is heat lost from the intake...

My answered was to this:
That is heat that is being pulled from the manifold from the cold air INSIDE the manifold.. not outside. Where does that air go? outside??? If you shut down the car... and touch the manifold it'll be hotter.. now why is that? because there is no cold air blowing inside and removing the heat.. Now is taking and taking and taking heat from the heads and not being removed by the cold air...

Actually I have my SS hood for it to cool inside.

 

As far as the intake manifold is concerned, the TBC on the bottom will reflect the heat that would be picked up from the lifter valley. Unfortunately there is still a huge amount of heat conducted through the connections to the head.... (TBC the gaskets? ). Putting a TBC on the exterior of the intake would seem to keep that heat in the metal, and allow it to be picked up by the incoming air. It would also increase the time it takes for the intake to "cool down" between passes.

 

Interestingly enough, we decided to coat my pistons, but not my heads or my Hogan's intake with a ceramic heat barrier coating, although I asked about all three.

I can't remember Mark's justification for not doing it off the top of my head, but as far as the intake is concerned, the design separates the plenum from the lifter valley plate, allowing a significant amount of air to circulate beneath the plenum. It'll still heat soak with the car sitting stationary (like anything metal under the hood) but once the car is in motion, I don't believe that there will be much of an issue, especially since the sheet metal doesn't have much mass to retain heat. Sound reasonable?

http://home.gci.net/~jimlab/images/Intake/PC050027.jpg
http://home.gci.net/~jimlab/images/Intake/PC050028.jpg
http://home.gci.net/~jimlab/images/Intake/PC050048.jpg

If we'd gone with an LT-style intake, though, at the very least we would have coated the underside of the intake. I don't know how much a "heat shedding" coating on the exterior surfaces of the intake would have helped, but we probably would have tried that too. It's a damn shame that no one has successfully developed a composite intake for the LTx yet.

 

Air circulation is not going to cool the intake enough in a "air gap" design like a Super Vic, RPM Air Gap or a Sheetmetal. The sheetmetal will heat and cool faster than a cast peice. It's still aluminum so it's still going to heat soak.

Jim, you had a $25K+ motor, so TBC is the right thing to do there. I know the intake wasn't $6K but it was alot. My $ values are there because I feel that there is more $ per HP elsewhere in the system. Then you go to coatings.

Compostite is the answer to most of these questions. Just like the LS6 intake.

Injuneer was dead nuts right in his post.

Think about a spacer Fred, phenolic is going to work better than TBC coated gaskets. Or a insulating spacer there.

All of this is just minor extra stuff. It's most likely not going to be worth alot (effort and $ per HP is low) but it can't hurt. Engines are not one thing, or a magic cam, they are alot of little things. Which ones make it the most powerfull for the budget.

Bret

 

Another take: It might also increase the time it takes for the intake to externally heat up from exhaust header heat during a dyno test which consists of a warmup pull then three consecutive pulls which are averaged. Cool-down afterward isn't important here.

At the strip, if you can delay the warming from underhood heat during burnout and staging, that is the same condition. Ya' gotta win the first round before you need to worry about cooling between rounds.

My $.02