ViribusUnits

Can a company NiCal, or hard chrom a pistion?

And if so, will it work in a 928 block?

Thanks.

John.

This is a good question that I was curious about....

You should call Millennium or US Chrome up in Wisconsin to determine if it is possible.

Remember, when you Nikasil a block you have to finish the job with a diamond tool, because it is exceptionally hard. There are probably tooling limitations, but either one of those places could tell you the answer to that question.

ViribusUnits

Good, at least I'm not barking up the wrong tree like I was a while back.

I'm woundering if that's what MB has been useing to coat their pistions for their new blocks. I've been trying to figure out what they use, but nobody seems to know. Not that I could afford it right now anyways, but there's always that off chance.

Fastest928

We spent thousands of dollars developing and testing a coating for pistons to run in the factory 390 bores and out of the 5 sets we have sold, one failed. They were sold as "developmental" products. This is the Witchita guy, who was at the time was motivated by our competitor to make a "scene" a the ICOC, you know. ...the one that Jim Baily and Z keeps mentioning...

From the diagnosis, it appeared that he overfueled the engine and skuffed a cylinder.

Unfortunately, due to the liability and a few aggressive and highly vocal "big mouthed" individuals, it is unlikely that we will offer this service again.

Marc
DEVEK

John..

Interesting topic, today I called Swain Tech to inquire about this....they have used a PC-9 coating on some pistons going into Alusil bores, but could not give me any assurance on what was to be expected, but that they had no complaints.

I think that would be a long shot. You could call Phil Threshie as he claims to have a coating that works.

Jim bailey - 928 International

The original Mahle pistons were chrome plated , Also KS pistons were iron coated both were used by Porsche and are OEM . Mahle's USA performance operation is now making replacement pistons in the US (968 104 mm ) . Reguarding the engine block ..Excerpt from PORSCHE Excellence was expected .........."For the 928 , Mahle became the supplier of the low-pressure die -cast cylinder blocks . Thoses were made of Mahle's 147 alloy , which was mainly aluminum with a sixteen-percent silicon content to provide the hard surface that gave the bores their durability . To suit the needs for the casting process the cylinders were free standing , the top deck of each bank of cylinders being completely open . " According to the book "Project 928 " .. the " high silicon content of 16-18 % and the brittleness inherit to such a material must be considered when designing mounting points " ..... So the free standing cylinders were a result of a manufacturing decision rather than a superior design (to allow die casting ) , the low pressure die casting is brittle due to the 16-18% silicon content , Both iron and chrome were used as an acceptable friction coating on pistons .