Ross or JE....?
 

Ok here is the story.

I just took my engine apart and had 3 cam lobes roached....long and short clogged spray bar. engine came apart so I could replace rings on some ross pistons that never seated. In the process my machinist engine guy (Michael mount in MD) said the cylinders were on the edge and not great so he talked me into sending them to millenium for re plating.....

Now I have refreshed heads with a 3 angle grind and properly shimed springs (on supposedly "rebuilt" heads @ 50psi/190psi VS 90/250 needed) new cams, EBS refurbed rockers, all seals and rings + nikasil cylinders being replated/bored.


Should I pony up for the JE pistons or will the Ross work. I hear a fair amount of bashing Ross out there? Is it true?

I NEED the straight facts quick as my cylinders will be in WI tomorrow!

thank you

Josh

JE aren't that expensive and the quality is very high. I know nothing about Ross except the name. Given the time and expense of a rebuild, this probably isn't the place to skimp.

Josh,

I won't use a Ross in anything; its CP, JE or Mahle,...:)

Steve, is this a departure for you? I once asked you years ago for a list of the top three piston manufacturers and it came out like this:

1) Mahle
2) Mahle
3) Mahle

:) But seriously what about the manufacturer whose name is the last letter of the Greek alphabet?

Have a good weekend :)

Also Josh, I would call Millenium and tell them to HOLD IT--

Buy whatever pistons you intend to use, measure them and then have the cylinders honed and plated to establish the correct clearance. This way you end up with a stock size piston and a custom cylinder, instead of a stock size cylinder and a custom piston-- you're more likely to blow a piston than you are a cylinder.

If only Cosworth still made Porsche pistons...they were nice.

A new, interesting alternative: Wössner makes 911 pistons of all varieties and are now cost competitive with JE (not sure why, but all prices used to be in Euro and they were way more expensive). They are a forged piston and appear to be of superb quality. They are German made and are a very interesting alternative because like Mahle, you can buy pistons AND cylinders from them. They also offer one thing Mahle doesn't: connecting rods, all made in house.

http://wossneronline.com/Porsche.php

I've used Ross pistons in other applications with good results, but never in a 911 engine. I wonder why their Porsche pistons don't do as well (I've heard)?

Hey John,

My bad,..I should have added context to my earlier reply but that was a simplified answer,...:) :)

For street engines and some race engines, we use and recommend Mahle P/C's, only. Its a longevity-durability thing.

For race engines where ultimate longevity is no concern and the need for higher compression ratios require a different solution, we use CP and JE pistons made to our specifications and an Omega made to our own design.

Horses for Courses, as they say. :) :)

Thanks for all your replies!......I am going JE 9.5 to 1 with the replated/bored nikasils. You are right and I should have her sorted very well by the time the Oct 31st DE is on @ Summit......I am DIEING to get this ole gal up to speed @ a track where its legal and SAFE!

Josh

Kenikh,

Cosworth do still make pistons http://www.cosworth.com/Default.aspx?id=1092689

They don't stock Porsche pistons and used to want an order for a minimum quantity of 48 pistons.

I suspect, but am not 100% sure that they may be manufactured by CP.

Also the green Xylan coating isn't quite as good a a genuine Molycoated skirt.

We have had a few sets of forged 81mm pistons manufactured in a 4032-T6 which have worked very well.

Most aftermarket pistons for 911s such as JE, CP and Ross are manufactured from 2618-T16 whch has a significantly higher coefficient of expansion and I think is less suitable for road use.

I believe that Mahle 911S pistons are made from an alloy that has similar amounts of Silicon to 4032. The higher silicn pistons also tend the suffer less with ring groove wear which is a consideration for high revving 2.0 litre engines.

Has anyone tried Arias or Wiseco?

Hi Chris,

Totally agree.

Mahle has used their proprietary high-silicon, low-expansion forgings since the early Sixties and its very very durable, albeit somewhat heavy.

JMHO, but I think Arias and Wiseco are junk, by comparison. Everyone (except Mahle) uses the same basic Alcoa alloys but its the design that separates most of these manufacturers.

Anybody have experience w Wossner?

Ross was the first aftermarket piston manufacturer I started using almost 20 years ago. They would work but suffered from the same problem the very first "Forgetrues" had... excessive skirt to wall causing piston slap and short ring life. Ross refused to endorse tightening the skirt to wall clearances citing "cold seizing" problems. As a result I moved on with JE and then CP. My problems with CP was customer service---after having Bill at Extreme Cylinder Head send them a sample Extreme Head they missed the piston dome to head clearance and then told me it would take weeks to fix.... I ended up making a fixture and fixing the problem myself---to the detriment of the compression number I was looking for. I then found the wrist pin clip grooves deformed when I refreshed that engine and I went back to JE. The CP's were lighter than the JE's, but not as robust. I would not use Mahle because of the customer service (non existent) and I cannot get what I want in a custom piston. Jerry @ JE has told me that all of their small bore pistons are soon to be converted to "SRF" or x-box design and that should negate the weight advantage of the CP. As far as mileage durability of the Mahle over the JE I would say that on my street engines I have run the skirt to wall down to .0011/.0013 and "hard" DFC'ed the skirt with excellent results as far as durability.
aws

Woessner seems well respected in European motorsport.