Did anyone had any trouble about about the piston clearance on the oil jets?

I'm getting a new set of pistons installed to my car and the piston is hitting the oil jets at the bottom of the cylinder.

 

I believe there was a problem with early production Arias pistons (which they quickly remedied). Are these the new Cosworth that have a clearance issue?

 

yes they are. Cosworth says they are unaware of such a problem.

 

It wasn't just the Arias. I had my CP pistons "clearanced" as well. Arias didn't step up when one of their early sets ruined a motor here in town, so I wasn't taking any chances.
Bruce

 

You would think cosworth would have done enough R&D to figure this out...

 

I had a set of the first Arias pistons and they had to be slightly "notched" by removing a little material. It kinda looks like a valve relief on a piston top except on the underside.

 

And Ross pistons.

 

it sounds weird to sell pistons that you haven't tried yourself. it is more weird that a company like cosworth does something like this.

 

Checking clearances should be done with every engine build.

Did Cosworth actually make those pistons or are they just rebadged Cosworth like their head gaskets (ie Cometic).

 

Cosworth actually did those pistons, they are producing these pistons along with the JUN stroker kit pistons. It isn't a slight clearance problem, it's a big one which should be done by Cosworth. Today they faxed me a paper which gives descriptions about machining the pistons, at least their tech support is better then their engineering dep.

 

Wow, this is very suprising for a company like cosworth. The piston oil squirter clearance issue was discovered well over a year ago, and CP, Arias, and others quickly adjusted the piston design. Of course, its a good idea for the machinist to check the clearances. I am glad they found this for you before running the engine.

Those pistons will need to be removed, and notched. I good machine shop can easily do this. Or maybe Cosworth will want you to send them back.

We are Cosworth distributors too, but havent sold any Cosworth pistons yet. I will bring this to their attention as well.

 

Ken Anderson from Cosworth called me today and said they can replace the pistons or send me a document showing how to machine the pistons. I prefered the document as the international shipping would cost me another 4-8 days. I think they're gonna revise their piston designs now. Up to that time, everyone be careful about Cosworth pistons, I'm sure that they are very strong but the design has flaws.

 

Ken Anderson is my contact at Cosworth as well. He will definately take care of this, and I am sure that all future piston sets will be properly clearanced.

 

I am accepting donations for my contribution to the community on the matter....lol

 

I think Cosworth should donate to the community