930 Piston Questions

esantia · 07-30-2018, 09:38 AM

Hi First Time Posting

Im rebuilding my engine and can't identify the pistons (previos owner upgraded to 98mm pistons. The only markings is a 1 and 89/3 etched on the top. One of them have a bend second ring land; can they be refurbish?

Ken911 · 07-30-2018, 10:06 AM

If the rest of them are as gouged up as that one they need replaced. The dents and gouges on the top at the edge make it unservicable. They need to be replaced in sets finding an exact match and correct wieght. not likely.

Trackrash · Trackrash's Garage

Here is a great read on evaluating pistons.

Evaluating UsedÂ* Pistons:Â*How to Determine if Your Pistons Are Still Good

esantia · 07-31-2018, 08:19 AM

Thanks!!

Is there a way to identify the Pistons they have a slight dome and are short skirt. The only ID is a 1 and 89/3. I want to send the cylinders with new Pistons to be recoated.

tom1394racing · 08-01-2018, 05:21 AM

I have a full set of these in good condition. PM me with your email if you have an interest.

Trakrat · 08-01-2018, 08:02 AM

Quote:

Originally Posted by esantia

Thanks!!

Is there a way to identify the Pistons they have a slight dome and are short skirt. The only ID is a 1 and 89/3. I want to send the cylinders with new Pistons to be recoated.

They look like custom JE pistons.

tom1394racing · 08-02-2018, 04:53 AM

I have this set.

I think these are the Ruf "Yellowbird" pistons.

TurboKraft · 08-16-2018, 04:01 PM

That is indeed an early 98mm Ruf piston, 7.5:1 compression.
If the ring lands are warped, there's no repairing it.