Thom

What are the "old" Mahle/Andial 104.5mm pistons made of?
I would guess Mahle specced them the same as the stock 100mm pistons?

Chris White

That would be my assumption based on the recommended skirt clearance.

Duke

Now I'm confused, I think you mean stock are more like the 4032?

Chris White

Sorry, yes! 4032...

Kpoeltl

I was just made aware of this thread and wanted to post a bit of information. For those of you who don't know me, my name is Karl Poeltl and I run Racer's Edge and we sell Wossner pistons among many other things. We do a lot of custom piston design work with customers to make sure they get what they want. Our(Wossner's) forgings are made for a "slipper" or "semi-slipper" design piston as opposed to a fully round design.

In a full race high boost situation a fully round style piston like the stock 944 Turbo pistons works great and was a great design choice when these engines were first designed and made. But technology has improved and we now have 600 HP 1.3 liter engines running a semi slipper style piston design, and it is this slipper design, not a fully round design, we use for 944's.

4032 pistons have better wear characteristics in an extended use application as 4032 is the most durable material for longevity in a high performance boosted application. Where 4032 noticeably excels in “performance” is that the 4032 piston need less clearance and do not have the knocking at start up commonly associated with a 2618 material piston.

2618 when placed under a load when the engine is not to operating temp seems to hold the shape better which makes them popular in very high boost drag race applications as those engines don't run very long before they are run hard and then shut off . For a max boost drag race application the 2618 is a great choice as the pistons can also be made a few grams lighter (not much however a little lighter).

I hope this helps regarding the pros and cons of both materials commonly used in today’s High performance engines. By the way, most of the OEM premium forged pistons are made from a material that is closer to 4032 than 2618.


Karl Poeltl
Racer's Edge Inc.

865-862-5262 voice
865-862-5271 fax

Charles A. Toupin

I also heard about Arias pistons, or something like that. How are they? Did anybody ever used them?

Tx

C.

95ONE

Charles, I've never had good luck with those in the high boost Honda scenario.

mikey_audiogeek

When I was crewing 15 years ago, our engine builder used to refer to Arias pistons as "block knockers". The pistons would stay mint but wear out the (cast iron) block pretty quick due to the clearance, they were a high clearance design. Strong, but.

Mike

Charles A. Toupin

Thanks Guy!

How long is it to get a set of stock pistons from Wossner?

C.

Kpoeltl

Wossner can deliver anywhere from 2-5 weeks. We average about 3.5 - 4 weeks,... it is completely dependent on production backlog.

Charles A. Toupin

So I understand that you don't keep in-stock inventory of that kind of pistons.


c.

Charles A. Toupin

I'm still a bit confused about the Arias pistons.

I went trought the site a little bit and I found that there were sets of pistons designed by Tom Charlesworth for 944/951 and made by Arias.

I understand that Mr. Charlesworth is very knowledgeable and that some rennlisters used these pistons and did not have any problems with them.

Any opinion on these specific pistons?

Thanks

C.

95ONE

Im pretty sure that I just read a post in the past few months that actually commented on how there were multiple problems with those pistons. maybe do a search.. I just can't remember if it was these exact pistons.

Charles A. Toupin

I did another search and I did not find anything wrong with those Charlesworth pistons. There is one guy who blew his freshly rebuilted engine and had those pistons, but who knows if it's the pistons or anything else. I think, maybe I'm wrong, that you have to be an extremely well qualified mechanic to be able to blame a set of pistons for a mechanical failure.

Actually, I will have to rebuild my engine this winter and there is one guy in Montreal who has a brand new set of them. They are coated too. And he has the steel sleeved block to with them. So it may be a possibility for me. Since I want a bulletproof, no hassle engine, I want to make sure I buy the good stuff, if I go this way. And since I'm running on a shoestring budget, the engine must not blow for the next 3 seasons at least.

Tx.

C.

Fishey

We had a set of failed 911 J&E's so this is the 2nd time the motor has come apart for crappy manufacturing by aftermarket sources.