ENGINE COATINGS - A REFERENCE THREAD

[falcongeorge]

This engine performed very well in testing, peaking at 545hp (6,400) and 500 ft-lbs. (4,900).

It's not "peaky" either. At 3,500 its making 415 ft-lbs and 280 hp. The average power numbers are really good all throughout the rpm range.

CR is 9.5:1 and cam is a Comp XR286 (12-772-8) solid roller. Heads are AFR CNC 215s, manifold is RPM Air Gap. Demon 825 carb, MSD ign.

Scott Parkhurst
Editor
Street Thunder Magazine

Mediocre cam, wrong manifold type and small carburetor.

Troy Patterson TMPCarbs.net TMP Carbs

I believe those are "magazine build" commandments # 2, 3, 5, & 1. #2, thou shalt not use mech. cams other than Comp XR series, #3 thou shalt not use ANY intakes other than rpm air-gaps, #5 thou shalt not use carbs that make excessive power, and #1 Most of all, thou shalt NOT, on penalty of excommunication, use a compression ratio that any sensible person would use when building a similar engine. #4 is Thou shalt not port , grind on or otherwise romance heads, or any part for that matter, just wash 'em and bolt em on.

[Troy Patterson]

That's funny falcongeorge!

I wasn't trying to discredit Parkhurst. He was one of the very first people in the magazines I talked to and was really nice and helpful. Then, with the Engine Masters for 2002 he wrote some really nice things about my carbs / carb building - even if the color of the pictures Pop Hot Rod published was screwed up.

After reading car magazines for some twenty years, PLUS reading all the car magazines my father had back into the mid 1950's, a guy with half a brain gets sick and tired of yet another engine's 101 article, or carbs 101 and I really hate and therefore stopped buying car magazines after reading the five hundred, seventy eight thousand, fifty seventh article written for non-car savvy college kids on a limited budget.

For Gods sake, every article doesn't need to be written for that demographic. I think it's an injustice to car guys and gals to limit the scope of the material.

I haven't talked to Parkhurst from some time, but I hope he's still a nice guy. I'm glad to see his success as Editor of Hot Rod. It's kind of interesting to ponder where I might be in the automotive racing world had corrupt Bureau of Auto Repair employees Roderick Baca and John Nelson and their friend John Bohannon of Los Angeles not sought to force me out of business criminally. But, I've got to give credit to the corrupt Los Angeles Deputy City Attorney Patrick Shibuya, City Attorney Rocky Delgadillo and others for complicity in an abuse of power, corruption and other crimes. It's not every city a hard working honest guy with drive, ambition and the better mouse trap can be forced out of business.

Troy Patterson TMPCarbs.net TMP Carbs

[Troy Patterson]

Troy wrote. "The fact is, the air flowing through the intake is all that cools it. If the intake is hotter, it is because less heat is absorbed by the air flowing through, which is what we care about. The temperature of the intake itself is irrelevant so long as the intake charge is cooler."

Exactly. I have been wondering for quite awhile now if there is a good coating that can be sprayed onto the runners inside the intake manifold. That would slow way down the rate of heat transfer from the hot intake manifold to the incomming air and keep it a lot cooler.

I'm about to install my intake manifold and sure would like to know the answer.

Boy, this is late in responding, but I use Techlines oil shedding thermal barrier coating such as used on the bottom of intake manifolds. Don't recall the exact name of it, but by that description is shouldn't be hard to determine which it is.

Troy Patterson TMPCarbs.net TMP Carbs

[falcongeorge]

That's funny falcongeorge!

I wasn't trying to discredit Parkhurst. He was one of the very first people in the magazines I talked to and was really nice and helpful. Then, with the Engine Masters for 2002 he wrote some really nice things about my carbs / carb building - even if the color of the pictures Pop Hot Rod published was screwed up.

After reading car magazines for some twenty years, PLUS reading all the car magazines my father had back into the mid 1950's, a guy with half a brain gets sick and tired of yet another engine's 101 article, or carbs 101 and I really hate and therefore stopped buying car magazines after reading the five hundred, seventy eight thousand, fifty seventh article written for non-car savvy college kids on a limited budget.

For Gods sake, every article doesn't need to be written for that demographic. I think it's an injustice to car guys and gals to limit the scope of the material.

I haven't talked to Parkhurst from some time, but I hope he's still a nice guy. I'm glad to see his success as Editor of Hot Rod. It's kind of interesting to ponder where I might be in the automotive racing world had corrupt Bureau of Auto Repair employees Roderick Baca and John Nelson and their friend John Bohannon of Los Angeles not sought to force me out of business criminally. But, I've got to give credit to the corrupt Los Angeles Deputy City Attorney Patrick Shibuya, City Attorney Rocky Delgadillo and others for complicity in an abuse of power, corruption and other crimes. It's not every city a hard working honest guy with drive, ambition and the better mouse trap can be forced out of business.

Troy Patterson TMPCarbs.net TMP Carbs

Yea, I was taking a little poke at the magazines more than Scott. But it does seem a little like they build the same 3 engines over & over again, doesnt it?

[falcongeorge]

I have a some of the Techline stuff, but I have yet to use it.

[ptuomov]

I am looking to machine a deeper dish into a stock 1987 Porsche 928 S4 piston, and considering a thermal barrier coating on top of the piston. The stock piston is originally coated with Ferrocoat, iron coating that allows the piston to run on an Alusil cylinder. The '87 piston has a thick top which was reduced to a thinner top in a later casting revision. Therefore, machining the dish of the 1987 piston is considered safe, but I am considering a TBC top to give the piston a better chance to survive.

Some questions related to coatings:

- Are there any issues with coating used pistons?
- Obviously, machining the dish will remove the iron coating from most of the piston top. Should I completely remove the iron coating from the area that is to be thermal barrier coated?
- I believe that the right way to prep the surface is with sandpaper. Does the grit depend on the thickness of the coating?
- The iron coating _must_ be retained on the skirts. How can those be masked off without damaging the iron coating? I don't want to rip it off with the masking tape.
- Does that iron coating suffer from the heat in the coating process?
- Where should I "draw the line" where the TBC top ends and the stock iron coating starts? Right at the corner of the piston? Needless to say that I don't want either coating to flake off.
- What will be the damage if the TBC flakes off? Does it end up in valve seats? Ring grooves? Valve guides?

Any other considerations that I am missing? Running aftermarket pistons for this particular engine is not an option.

[ptuomov]

I am looking to machine a deeper dish into a stock 1987 Porsche 928 S4 piston, and considering a thermal barrier coating on top of the piston. The stock piston is originally coated with Ferrocoat, iron coating that allows the piston to run on an Alusil cylinder. The '87 piston has a thick top which was reduced to a thinner top in a later casting revision. Therefore, machining the dish of the 1987 piston is considered safe, but I am considering a TBC top to give the piston a better chance to survive.

Some questions related to coatings:

- Are there any issues with coating used pistons?
- Obviously, machining the dish will remove the iron coating from most of the piston top. Should I completely remove the iron coating from the area that is to be thermal barrier coated?
- I believe that the right way to prep the surface is with sandpaper. Does the grit depend on the thickness of the coating?
- The iron coating _must_ be retained on the skirts. How can those be masked off without damaging the iron coating? I don't want to rip it off with the masking tape.
- Does that iron coating suffer from the heat in the coating process?
- Where should I "draw the line" where the TBC top ends and the stock iron coating starts? Right at the corner of the piston? Needless to say that I don't want either coating to flake off.
- What will be the damage if the TBC flakes off? Does it end up in valve seats? Ring grooves? Valve guides?

Any other considerations that I am missing? Running aftermarket pistons for this particular engine is not an option.

We didn't end up coating this round of pistons, but I'd greatly appreciate comments on these questions for the next round of experiments. The goal is not to make more power, the goal is to lower the piston temperature and increase reliability.

[groberts101]

I am looking to machine a deeper dish into a stock 1987 Porsche 928 S4 piston, and considering a thermal barrier coating on top of the piston. The stock piston is originally coated with Ferrocoat, iron coating that allows the piston to run on an Alusil cylinder. The '87 piston has a thick top which was reduced to a thinner top in a later casting revision. Therefore, machining the dish of the 1987 piston is considered safe, but I am considering a TBC top to give the piston a better chance to survive.

Some questions related to coatings:

- Are there any issues with coating used pistons?
- Obviously, machining the dish will remove the iron coating from most of the piston top. Should I completely remove the iron coating from the area that is to be thermal barrier coated?
- I believe that the right way to prep the surface is with sandpaper. Does the grit depend on the thickness of the coating?
- The iron coating _must_ be retained on the skirts. How can those be masked off without damaging the iron coating? I don't want to rip it off with the masking tape.
- Does that iron coating suffer from the heat in the coating process?
- Where should I "draw the line" where the TBC top ends and the stock iron coating starts? Right at the corner of the piston? Needless to say that I don't want either coating to flake off.
- What will be the damage if the TBC flakes off? Does it end up in valve seats? Ring grooves? Valve guides?

Any other considerations that I am missing? Running aftermarket pistons for this particular engine is not an option.

We didn't end up coating this round of pistons, but I'd greatly appreciate comments on these questions for the next round of experiments. The goal is not to make more power, the goal is to lower the piston temperature and increase reliability.

Tight on time here.. but I would not recommend sanding by hand. Ideally you use a lower pressure(30-40 psi depending on equipment usually does the trick) medium to finer blast media to create sufficient surface profile to maintain proper adhesion.

Do the entire crown all the way to the topside of the top ring land. Piston is smaller there and never contacts bore anyways.

Not familiar with that factory coating but I can only imagine an iron based oem coating application temp would easily exceed the 300-350 curing temps needed for these coatings. Blue low tack tape is very gentle to use during the prep for application process. Only problem there is you'll need to cover that low tack tape with duct tape to keep a nice sharp tape line while sand/glass blasting. My guess is if low tack tape.. or any regular tape for that matter.. could easily pull material off the skirts?.. then you're likely going to be looking at some type of oem coating failure anyways. Should be fairly tough considering the extremely hard cylinder coating it's riding against. But surely pays to check with someone familiar with them before considering these coatings.

Durability. Need a filter for sure or you risk small particles damaging the relatively softer coatings over time. Also need to add very small radii/broken edges to all coating areas(valve reliefs/crown edges/dishes) or they will be the first to chip away. Obviously need to do that before final blast prep.

Not sure what power or application here.. but in theory.. and what I do to fully capitalize on all the extra cost and effort.. is to allow slightly tighter piston to bore and few thou off the ring gaps due to less heat and therefore piston expansion. Probably many videos on that subject if you hunt for them. Might even find some at the mfgrs websites too. About all I have time for right now.

[Casper393W]

Wow this thread had some age on it!

[bentvalves]

I sent some pistons out to cal i co to get a thermal barrier applied to the tops for a turbo app.

the one piston that was out of the box for a few days or so sitting on my wooden bench, crown down and being moved about while measuring the skirt....the coating in a few areas of the piston appeared to be getting "wiped" away.

Id love to see how the coating holds up to combustion temperatures/pressures/light detonation.