Oversize Pistons

[mcandmar]

Looking for options for oversize pistons, what brands have people used?

So far i found....

Mahle = seem to cost more than customs
JE = I know some of you are using them, any issues?
Eurospec = Havent heard anything good or bad about them?

... I need more suggestions please, the cheaper the better

Mark.

[S2central.net]

I think MarkH bottomed out all the issue with JE. Seem to recall they had some thin edges in the valve pockets which had the potential to melt under severe load.

Someone else is using them - Doug or Jeffer ? I can't recall...

Paul

[Erikb]

Jeffer uses JE.

Besides JE and Mahle you also have Wiseco, I dont have any experience with these so dont know if they are the same quality as JE and Mahle.

I thought a member on this forum, audspeed, was selling them. I believe also in oversizes.

Erik

P.S. here you have some more info about the wiseco pistons http://www.importperformanceparts.ne...ons-eaudi.html

[Mark Halligan]

I think MarkH bottomed out all the issue with JE. Seem to recall they had some thin edges in the valve pockets which had the potential to melt under severe load.

Someone else is using them - Doug or Jeffer ? I can't recall...

Paul

The set I had made after that were much better, I asked them to machine away the sharp edges and they did.

[cochemaniax]

Hi,

i´ve seen pistons for a 5xxhp S2, they are called in german "Kastenkolben", google
translated: BOX PISTONS, slipper skirt piston says my english friend.

The pistons of this S2 were coated on the side with graphite, i don´t remember brand, but i guess it was MAHLE.
Found an other example:https://www.cbperformance.com/catalo...productID=1429
just for information!!!

[CR500Dom]

I am amazed no one has talked to Cosworth

Not that they advertise the fact but they probably have a fully forged piston for the 5 pot already.

If not they can do you whatever you want.....

Minimum order size is 8 pistons normally so 2 sets and you could have a fully forged F1 spec slipper piston for whatever C/R you need..... and the best bit is, they normally work out about £80-£100 a peice with rings

Seriously, some of you big HP guys should talk to them, Having worked there and got to know the Piston guy Julian very well, I can honestly say, you will not buy better quality pistons anywhere, and all customer pistons go through the same shop as the F1 pistons They do Pistons for Jun in Japan and their mega HP Skylines and Evos, Race bikes, cars, MXers, etc they have Forge tools for pretty much any incremental bore size you could wish for as well

https://www.cosworth.com

You wont regret it
HTH
Dom

[RSCoupe]

The set I had made after that were much better, I asked them to machine away the sharp edges and they did.

Mark, what bore are those? I just got some JE's from 034Motorsports (034EFI) and the sharp edge is not a problem. But it might be because they are 83mm.

I can take some pictures, but it will have to wait until after Christmas, as the wife wrapped them up, and I have to wait.

[Mark Halligan]

I can take some pictures, but it will have to wait until after Christmas, as the wife wrapped them up, and I have to wait.

LOL, They are 82mm, I've seen the ones from 034, they do look nice, I've noticd that the dish looks a bit deeper too, or maybe thats just the pic I was looking at?

[olsonjus]

What sized dish do your JE's have Mark? The intake manifold looks killer Btw.

Regards,
Justin

[olsonjus]

www.034efi.com

[volcano rs]

i know someone who has 528 bhp rs 500 cossie and he said he uses audi rs2 pistons

[RSCoupe]

LOL, They are 82mm, I've seen the ones from 034, they do look nice, I've noticd that the dish looks a bit deeper too, or maybe thats just the pic I was looking at?

I don't remember. I only had a chance to make sure everything was in the box, then it was taken away. I'll know more in 8 days.

[mcandmar]

Wow lots of options, thanks guys

@Mark: did you alter the spec of the pistons in any way? Dish, valve recess etc? and which rings did you use?

Going to leave the block in next week to be machined, hopefully we can get away with a .25mm overbore.

Cheers,

Mark.

[Mark Halligan]

Wow lots of options, thanks guys

@Mark: did you alter the spec of the pistons in any way? Dish, valve recess etc? and which rings did you use?

Going to leave the block in next week to be machined, hopefully we can get away with a .25mm overbore.

Cheers,

Mark.

Mark

I speced them for 8.0:1 comp ratio and JE calculated the dish size to that, the valve pockets are 1.5mm deeper than standard. The ring grooves I am using are 1.2mm top, 1.5mm second and 3mm oil ring.
The rings I am using are the Gapless top ring set from Total Seal, not everyones cup of tea I know, but I am going to give them a try.
Other than that though JE themselves do rings and can supply rings with the pistons, if you are ever stuck for a set of rings, try giving a fella called Dave a ring at http://www.performanceunlimited.co.uk/ really helpful .

[twoqu]

Hi!

Twas a while back but my local engine shop offered me a set of KS pistons for £400 inc VAT, including rings/pins. I don't think they could get the first oversize so these would have been 0.50mm o/s.
These are forged but std. Think there is some debate about the OE fitment whether it was Mahle or KS or a bit of both. I have heard that German companies had to source stuff from different suppliers.
Perhaps those who have paid close attention can tell us.