cylinder coatings

JAyers93

JAyers93

C15H28
Joined
Jan 25, 2009
Messages
277
Has anyone ever experimented with any of them? Specifically nickel carbide silicon (NiKaSil) or Low Temperature Iron Titanate (LTIT)? Increased wear resistance, reduced friction, and also helps to get us a little closer to an adiabatic cylinder...

Any insight of past experience would be greatly appreciated.
 
My buddy tried some NiKaSil coated sleeves in his super farm tractor. they didnt last, the stuff was flaking off. i dont know why, maybe a manufacture flaw. there werent any burnt pistons. he said some other guys were having the same problem. he went back to the regular uncoated sleeves and hasnt had a problem since. thats all i know in the subject.
 
I know the coating used by Honda in my old CR250 dirtbike held up great long-term.... but it wasn't a high compression, high temp, diesel motor either.
 
Most of later model 2strokes weren't even sleeved. They used a nicasil coated aluminum cylinder. I have seen pistons seized badly and the the cylinders looked great.
 
Nicasil is tough stuff. When my outboard melted a piston and left aluminum in the cylinder all I did was soften the aluminum with some muriatic acid and it honed right out. The cylinder still looks new.
 
It seems to be hard to apply correctly to cast iron but there are a few places that can do it and will stand behind it. Kind of steep to have done at around $250 a cylinder tho.

All 450r trx or crf honda's are currently coated as well. Im sure honda uses it on all of there aluminum cylinder engines. There are also people running 13.5-15.5:1 compression turning them to 10k+rpm at normal operating temperatures and they seem to be holding up.

Im curious if it would be cost effective, mainly concerned with the engine output increase from reduced friction and less heat lost during the cycle. The link below shows an increased brake specific fuel consumption of 6.5%. Seems pretty impressive, might have to make some phone calls.

Also ive heard of the army using the LTIT coating in their diesel tank engines but it is hard to find any info on the outcomes or even if they still use it. It also seems to be far superior to NiKaSil as far as ring seating and wear in diesel conditions.

This is the best info ive found on the subject so far.

http://www.adiabatics.com/Advanced_Engine_Concepts.php

The PDF's have some interesting info in them.
 
We had some blocks done with TiN coating back when we messed with alcohol pulling engines with good results. Haven't worried about it much with the diesels. Blocks don't stay together long enough anyway.
 
One thing to think about...

All of the coatings have crappy thermal conductivity, so piston cooling via the rings probably drops like a rock. The under piston cooling jets would have to do basically all the cooling....so maybe with the TBC on the crowns, it's all good.

I would think a hi-po motor would be hell on the coatings.
 
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