I bought these pistons from a guy in the UK who had them custom made by Ross over 18 months ago.
They are for a std bore LS1, 0.944 pin to take a std LS1 rod with a fairly big dish for low CR ( too low, but anyway ).

Ive only just started to assemble this engine, but come across a nasty problem. The pins are a press fit in the rod, and I had them fitted locally. They were not pressed in, but the rod heated and pins hand fitted.

As can be seen in photos these are brand new.

Is this a crack ? or some strange mark ? It unfortunately does look like a crack or casting flaw of some sort.
Im assuming this piston is scrap ?



[

Photo taken using mirror ( trimmed to size, mirror has a crack, but piston mark is clearly seen ) )


Whats the story with this ??

 

I wouldnt use it... that sucks.

 

The crack shown doesn't look too pretty. I wonder if there might be a burr
cutting into the pin?

I'd also question the pitting seen in the top photo.

 

Pitting where ? Theres a little bit of dirt on the pin from the cloth I wiped the oil off to take the photos...

The piston runs smoothly on the pin

 

That is very odd. Most of the time when a piston cracks it cracks all the way across.
IMO you have a very exsensive paper wait.

 

I'd understand a crack if they had been used or something. They are brand new. They've just been lying since I bought them ages ago.

 

You could get ross to make you one to replace it. It would be easy if you have the spec sheet. I definitely would not use that one though.

 

They want to speak to me on the matter, although due to time difference and the weekend havent been able to yet.

TBH I dont even want to be using these pistons, but I have them, and dont want to be spending any more money.. I bought them over 18months ago, and at the time knew little about the LS1, but bought them with lots of other parts. With hindsight it was a bad move. They were made to suit stock rods, which means there are virtually no aftermarket rods that will work ( 0.944pin )
The dish is massive at about either 30 or 34cc. The guy who had them made wanted a ridiculously low 7.0:1 or something crazy.

Ive tried messaging a few sponsors about a cheap rod/piston package for a more sensible 8.0:1 CR or maybe a tad higher. Still havent got a response from any of them yet though. Though anything I get must fit a stock bore size. Any local machine shops wouldnt even know what a deck plate is here, and would probably **** up boring/honing to suit oversize pistons.
Im pump gas only, and pump gas in the UK isnt as good as what you guys get over there. 8.0:1 should be good for 20psi or so though...which would be cool. probably 15 or 16psi will be enough though.