refresh951

They came out of a 3L motor we tore down. They have a number stamped on them "39507". TIA

V2Rocket

16v?
Alusil?
First guess for your region would be Broadfoot custom JE, or maybe Vitesse if he was in the piston business?

refresh951

8V, Nikasil is what I was told. Bad things happened with a lot of cylinder scoring. Block will now be sleeved.

333pg333

Did you actually tear it down Shawn? Assuming you would have seen the damage and I'd imagine been able to tell it was Nikasil surfaced. How long was the motor together for? Doesn't look very long. Who built / supplied it?

refresh951

Motor was built in the ATL at a local Porsche shop. Motor ran for 5 minutes. Pretty much a disaster IMO. Definitely Nikasil. The guy who built the motor has since passed away.

333pg333

Wow...quite a story! Would love to know a bit more about it if you find out? Cause of failure etc.

gruhsy

I googled 39507 pistons and it brings up Diamond pistons......you probably did that already....but thought I would check.

333pg333

http://www.diamondracing.net/

Might be worth contacting the company and see what history they have for this build.
Find out why it failed so quickly. Were the pistons/rings treated to run in Nikasil?

gruhsy

If it is the same material piston as what I googled but just a different design

http://www.cnc-motorsports.com/diamo...-040-bore.html

The one on the link above shows 2618 material....going by Diamonds explanation of 2618 compared to 4032 you need more piston wall room for the 2618 compared to their 4032.

http://www.diamondracing.net/faq/ see cut and paste below

What material are your pistons made from?
We use two different materials, 2618 & 4032. 2618 is used in most of our severe duty / power adder applications. It requires slightly more piston to wall clearance and can stand up to the abuse of a power adder. 4032 is used for applications that are more on the mild side. 4032 has less of a expansion rate which allows us to use it with tighter piston to wall clearances. This is great for direct replacement factory pistons. Call one of our tech's and they will let you know which material is good for your application.

So maybe pistons are 2618 and there was not enough room for expansion?

Or I could be totally out in left field

refresh951

Thanks! We contacted Diamond. Part number is a Ford Piston. Specs do not line up in any way. Still a mystery.

michaelmount123

The forging is intended for a Ford - they just used that forging for what you have. The dish is typical of 2V turbo. Looks like someone also had them lighten the underside. If you're going to use them you'd better check the crown thickness to ensure there's plenty of meat.

Humboldtgrin

Maybe the intake manifold was extrude honed and not totally clean? That's taken out engines pretty fast.