How about friction coatings....anybody try em? - Page 2

afterburn 549 · 10-03-2005, 07:03 PM

I dont do it all but send them to my vendor on E.coast, as far as ports and heads it will depend on aplication of how much and where you need it.
And yes ceramic the tops

ttAmRoadsterAWD · 10-03-2005, 07:04 PM

Oh, BTW, anybody ever have a turbo damaged from pieces of coated piston tops/combustion chamber peeling off and exhausted down to the turbos impellers? Sounds risky if you have turbos down there waiting to "filter" those ceramic chunks!!

How 'bout it Mr. Navarro or anybody

Jaime

afterburn 549 · 10-03-2005, 07:52 PM

NO,this is proven stuff guys,not snake oil, do some home work you will see the light

cnavarro · 10-04-2005, 05:02 AM

Never have I heard of the coating flaking off unless the parts are not prepped properly. I had a small outfit out of oregon do my personal heads on a 914 engine and they didn't prep them right and all the coatings could be removed with just a fingernail- it was that bad. That's why I don't recommend doing them at home, although I have tried stuff like the techline thermal disperants and done them myself with excellent results. But again, that's an external coating that won't hurt anything if it does fall off. Inside the engine, that's a totally different story. I'd leave it to the pros- Calico or Swaintech. There are others, but I like the comfort that these two companies do the majority of race components regardless of industry. I've also spoken to them personally at the PRI show and have faith in their processes and services. Never have I had a problem with either.

ttAmRoadsterAWD · 10-06-2005, 11:39 AM

Hold the press!! I just got back my headers from Swain. They did a great job of applying the ceramic on the exterior......BUT, unfortunately (?) they also purposely sprayed the inside of each header as well as the collector at the other end, prior to the turbos! I spend a good amount of time cleaning up welding material and sanding the interior of the headers only to get them back coated. They have effectively decreased the diameter of my headers...should I send them off to get them extrude honed? Do you think it matters on a turbo engine?

Jaime

cnavarro · 10-06-2005, 12:18 PM

I personally think that the coating on the inside should help the headers last longer and won't decrease the flow. If anything, the coating should be fairly slick. As long as they didn't coat any sealing surfaces. Those I would have bear metal unless someone thinks otherwise. Suggestions?

jluetjen · jluetjen's Garage

How thick is the coating that we're talking about? What % of the total cross-sectional area did you lose? I've heard of people purposely using smaller cross-sectional headers to decrease the total volume upstream of the turbo. This was supposed to decrease turbo-lag since the engine doesn't have to pump up as large of a plenum volume prior to the turbo spinning up.

ANTONIO · 10-06-2005, 02:17 PM

For a turbo aplication, I never coat the headers inside, the material (mild steel,stainless,etc.)expands and contracts too much, and it is prone to flake out ,plus if it get striked by an object it may crack inside,imho it is a no-go.,cheers,Antonio.

afterburn 549 · 10-06-2005, 02:29 PM

as to how thick....will very from vender to vender and "where it is being applied. Pistons will be very small (so you do not have to add multiply and subtract for the bore)

cnavarro · 10-06-2005, 02:33 PM

Antonio made a good point on coating the insides for a turbo application being a minus if flaking were to occur. I always forget when we switch our discussions between n/a and forced induction that I have to change my way of thinking, since I deal mostly with normally aspirated where it really doesn't matter if it were to flake off.

I typically never coat skirts on the pistons if the proper clearance has already been set up. In most cases, we're running .0015" total piston to cylinder clearance and the skirt coatings start at .001" thick on diameter, so you can do the math. You end up with a piston that either can't be loaded into the cylinder (or) it's too tight, regardless of the fact that the coating will scuff and wear off upon break-in.

snowman · 09:28 PM

Jaime,

Coating on the inside of headers is certain NOT to affect the flow in any way, period. GIve me a break, out of the total area of a header, the coating is so insinigficant as to be assinine to even talk about. The subject of flaking off is another matter. THe coating may very well flake off, (highly doubtful if applied correctly) but will it do any damage??? VERY VERY doubtful.

Sorry for the choice of words, but I couldn't think of anything more fitting. I bet you cannot even CALCULATE the decrease in flow, let alone measure it, and thats assuming its a decrease! As bad as saying that you can get 10,000 percent increase in power with headers.

As to the benefits or lack of for coatings, lets put it this way. The BIG BUCKS guys of NASCAR all use them, extensively. Why? because they DO NOT WANT TO WIN?? They use them, because, used intelligently, they work, and work well. Swain Tech has some good info in how they work. And if you go with a coating only go with one of the two companys that work. Swain or the second best.

ANTONIO · 10-07-2005, 05:22 AM

For me HPC is the only one that I use.Cheers,Antonio.

ttAmRoadsterAWD · 09:53 AM

Gawleee, snow....I feel b*tch-slapped ;-) I have no problems accepting these coatings as helpful adjuncts, but I did have a question (note the "?"on my post) regarding its use inside the header. To think there is no delta from having the inside coated with a measurable thickness, no matter how thick is plainly careless. Maybe its splitting hairs, but even NASCAR would have studied the effect on performance due to the reduced lumen diameter......trust me!

Antonio brings up a very valid point.....thermal expansion. With heavy heat cycles between hot/cold there will be room for at least partial coating failure. If or when this happens, there will be an expensive filter (turbo) to catch the clumps. This wouldn't be a problem for NA engines, but I'd rather not take a chance with a turbo engine. I'm going to make arrangements with Extrude Hone to help me out on this one.

Jaime

cnavarro · 10-07-2005, 06:31 AM

At least that way you'll know the insides are nice and smooth :-)

snowman · 10:41 AM

What about those little chunks of carbon that flake off the cylinder and piston? If they do not trash the turbo, its very doubtfull that paper thin specs of coating, not chunks, will do any damage. Furthermore any specs of coating cannot get into the turbo bearings via the exhaust system. Typical coatings are only 1 to 3 thousands of an inch thick, not a source of "chunks". Flakes maybe, but flakes that are very fragil and would easily pass thru a turbo. The tolerance for making header pipe is much greater than the total thickness of any coating. If the coating thickness were enough to hurt the flow, the extrude hone process will certainly damage the flow, as the pipe inside diameter would end up being to large. But it won't because it isn't that critical.

Maybe I was a bit harsh, but understand that coatings are at the most like a coat of paint, and thats the thickest ones. Most are so thin that they do not even affect the dimensions of the parts that are coated. Even the coatings that many beleive wear off, like on piston skirts, are still effective even though only a microscopic thin layer remains after a couple of thousand miles..

ttAmRoadsterAWD · 11:59 AM

You have a point regarding flake vs chunk.....at the heat collector of the header, where the heater ducts connect, they also sprayed all around. Because the ceramic was sprayed onto a thin edge there is some cracking right at the edge. I was able to peel off with my finger nail maybe a 2X4mm "flake" off and let me tell you that a turbo with clipped impellers, seeing upwards of 175K revs/min will see this flake as a chunk. I've seen carbon flakes...literally like the flakes one feeds goldfish. Very light almost transluscent. Swain is thick. maybe 2-3 sheets of paper thick. They even let you know that's what sets them apart from other companies doing the same. Lubrication seals is not the worry, its the blades that come in contact with this flake that would impart enough energy (loss of momentum) that it could unbalance it. Anyway...best not to have anything waiting to happen.

I do appreciate all the shop talk though, makes it fun. All we need a beer or two.

Jaime

ANTONIO · 10-07-2005, 12:14 PM

I while back I was playing with water injection, injecting water before the compressor, and belive me after a while even the water eroded the compressor tips,as Jaime stated,is not the size of the chunk but the force and velocity of it that matters.,cheers, Antonio.

afterburn 549 · 10-07-2005, 12:22 PM

Can I say something..WILL you listen to Snoman!! and tune in. the stuff on my pistons I believe is about 2/10 of thou. maybe once in awhile a flake will come off...not like water running strait threw.............This application has been around for along time.....Give it up already!

ttAmRoadsterAWD · 10-07-2005, 12:47 PM

LOL, Afterburn....did you read my entire post, three posts above this one? Swain Tech ceramic coat is NOT, NOT, NOT thin!

But yeah, let's let it rest now.

Jaime

ANTONIO · 10-07-2005, 01:50 PM

I'm not talking about coatings on pistons,cyl head,etc, I'm just saying that coating the inside of headers for a turbo aplication is a no-no.