Cryo treatment and barrier coatings? (thermal etc)

[artificialist]

Originally Posted By: A_Harman
Originally Posted By: carock
1. Thermally coating the exhaust valve face reduces its temperature several hundred degrees. I only know this because David Vizard told me so. I figure David Vizard knows his stuff and knocking a few hundred degrees off the valve temperature has to be a good thing for longevity.



I'd think twice about thermally coating the exhaust valve face. That will turn it into a hotspot in the combustion chamber and make the engine more susceptible to detonation or preignition. If you want to lower the valve face temperature, put beryllium copper valve seats in the cylinder head.

Wouldn't using sodium filled valves accomplish the same thing, but enable you to use steel or iron valve seats?

 

[DP78]

While anecdotal at best my friend had every rotating item contact surface in his Hayabusa engine treated with a coating that was supposed to reduce friction. He had the bike dynoed before and after treatment. There was an improvement in dump numbers and at the track in trap speeds and times. Unfortunately, he got a little overzealous with the treatment and did the piston rings too. This obscured the marking for orientation and the engine didn't last too long. Mach Modified offers a coating of some type, I'm not really sure if it's thermal barrier or not, but they have shown improved wear factors over bare parts.

I think on a case by case basis, there can be improvements everywhere. I think on an assembly line it's lowest cost. Period.

 

[carock]

[/quote]

I'd think twice about thermally coating the exhaust valve face. That will turn it into a hotspot in the combustion chamber and make the engine more susceptible to detonation or preignition. If you want to lower the valve face temperature, put beryllium copper valve seats in the cylinder head. [/quote]

I have not done this yet, so I cannot verify. David Vizard said the exact opposite, the exhaust valve ran cooler and eliminated the hotspot. The effect was substantial enough to allow him to raise the compression several points.