Mahle or Kolbenschmidt Piston Set

[Andres]

Like thread title says. Does anyone know where I can find a Mahle or Kolbenschmidt Piston Set? I've searched on-line but not much luck.

My 3.2L is being bored and I need a new piston set.

The machinest said that Wiseco pistons have a clearance of .003 - 004. He said they arn't ideal for a motor that is going to remain NA and used for longevity. They would be fine for a race type motor that is expected to be rebuilt after 60K.

He highly recommended Mahle or Koldbenschmidt as they have factory clearances of .0007 - .0015.

[ParadigmGuy]

I recommend CP, not sure on the clearances though.

[Andres]

Anyone else want to chime in?

Paradigm do you have a link for a good CP distributor? I'll look in to them.

[ParadigmGuy]

Yep, Boost Logic (http://www.boostlogic.com) is a great place to get 'em.

[Andres]

Those CP pistons sound nice but they are low compression pistons.

I'm looking to stay NA. I'm not planning on changing my compression.

[Andres]

Anyone else?

[rustamd]

Anyone else?
You dont have to get low compresion pistons, they are custom made to order.

[Andres]

You dont have to get low compresion pistons, they are custom made to order.
good to know. I'll check them out again then

[Def]

If you are staying NA and rebuilding the engine - definitely up the compression ratio. These engines should take 11.0-11.3:1 on 91 octane with good tuning, and up to about 11.7-12.0:1 on 93. Honda guys have run much more(highest I've heard is ~13.5:1 on 93 octane, but that's probably not that hot of an idea).

11.0:1 is a pretty conservative bump in compression ratio though, and should net you a bit more efficiency(more power, and better gas mileage). I wouldn't try to pinch pennies and fill up with 87 after doing that though, as you'd better hope those knock sensors are working(if they can even make that much of a difference)!

I believe you can find high(I think it's high..) silicon content forged pistons - which have less thermal expansion than low(again, I think I'm right) silicon forged pistons. This allows you to run a bit tighter cylinder wall clearance, which keeps piston slap to a minimum on a cold start. Cast pistons(like OEM replacements) have even less thermal expansion, which is why you can run less cylinder wall clearance than forged goodies. It's not a quality control issue or anything, just a by-product of how they're constructed.

[Andres]

Thanks for the info Def.

I am hoping to get something with OEM clearance if possible. I want to minimizethe amount of piston slap.

Bumping the compression raito would be a plus but in all honestly I just want my M back on the road. 3.2-3.5 liter OBD1 is at a happy power level for me.

*edit* Do you know where I can find pistons like those you speak of? Like I said above my machinist spoke well of Mahle and Kolbenschmidt.

[eat M3]

im a little late for ya probobally but im running forged JE pistons, 11.5:1 compression, had the 3.0 bored a tad bit. So check out JE

[Def]

I'd just go with some Mahle pistons in the first factory overbore size then. Arias makes high silicon forged pistons though, but you'd probably have to wait for them.

You could always have your head shaved a little to bump the compression ratio up while you're in there. Nothing major, just a few thousandths to move it in the right direction.

[Andres]

Update

I ordered a piston set from www.bmwpistons.com (site has been down for a few day). They are affiliated with Barvarian Engine Exchange.

bmwpiston has a much better description but I ordered MaxSil pistons.
Here is Barvarian Engine Exchange description:

" Now using MaxSil™ BMW Pistons exclusively for all rebuilt BMW street applications. MaxSil™ pistons are manufactured using 13 percent silicone content for reduced friction and heat expansion - allowing for tighter cylinder clearances and longer engine life in standard street and mild performance applications. Five year, unlimited mileage warranty on pistons. New for 2004 are Tefcote™ coated piston skirts for even more friction reduction, performance, and fuel economy. Manufactured to ISO9002 and QS9000 quality certification. Precision cast and CNC machined for consistent quality."

My machinist said they looked like Mahle pistons to him and they would do the job fine.

.5mm overbore. They have a clearance of .0015 which is factory. Factory is .0007 - .0015. I wanted to minimize piston knock as I do not plan on ever rebuilding this engine again

Oh and if you are curious why I didn't bore more, it is because I already have a OBD 1 3.2 liter. I didn't want to make the cylinder walls weaker by boring more. Trying to be as cost effiicent as I can be. I just want to get the M back on the road and have some fun.

The machinist said my displacment will barly be changed. I was hoping I could say 3.3 liter and confuse people :laugh . The head will be decked for flatness and mild minimal amount so I'll have a tiny bit highier compression but nothing to note.

[rustamd]

How much did it run you?

[Andres]

$818 shipped.

Not great but definitely not as expensive as other choices.

[rustamd]

my freind just got wiseco's for for about same, so you know you didnt get raped

[BaLLZacK]

Thats awesome that you are going to stay NA :buttrock. I was looking at doing something like this aswell or just going with a Euro engine. Good luck, keep us updated and definitly post a dyno if you do one.


ALi

[str8 gone]

They are affiliated with Barvarian Engine Exchange.

" Now using MaxSil™ BMW Pistons exclusively for all rebuilt BMW street applications. MaxSil™ pistons are manufactured using 13 percent silicone content for reduced friction and heat expansion - allowing for tighter cylinder clearances and longer engine life in standard street and mild performance applications. Five year, unlimited mileage warranty on pistons. New for 2004 are Tefcote™ coated piston skirts for even more friction reduction, performance, and fuel economy. Manufactured to ISO9002 and QS9000 quality certification. Precision cast and CNC machined for consistent quality."

My machinist said they looked like Mahle pistons to him and they would do the job fine.
Those bavarian pistons are made by SEALED POWER,(trw/federal mogul),and at the price that bav wants for them I'd say one would have to be insane to pay for them.Sealed power pistons for a v8 average out to about 30-50 dollars per piston which is approx. $320-$400 for a set of eight.Having said that,I can't justify spending $800 plus simply because the application of the said bavarian pistons is BMW. Beside the fact that they have the teflon coated skirts, there is nothing special about Sealed Power products.The catch here is that Bavarian is the only place to get them so they feel that they can charge what they want to.Keep in mind, o.e. pistons from the dealer are insane $$$. Bavarian charges about 50% of oe prices but nonetheless they are still rediculously overpriced for what they are offering.All this being said as I search for a set of s50 pistons myself. :rolleyes

[Andres]

Pistons arrived today

http://i6.photobucket.com/albums/y234/Senpai_Racing/1995%20BMW%20M3/MaxSil%20Pistons/th_Pistons.jpg (http://i6.photobucket.com/albums/y234/Senpai_Racing/1995%20BMW%20M3/MaxSil%20Pistons/Pistons.jpg)
http://i6.photobucket.com/albums/y234/Senpai_Racing/1995%20BMW%20M3/MaxSil%20Pistons/th_MaxSilPiston.jpg (http://i6.photobucket.com/albums/y234/Senpai_Racing/1995%20BMW%20M3/MaxSil%20Pistons/MaxSilPiston.jpg)
http://i6.photobucket.com/albums/y234/Senpai_Racing/1995%20BMW%20M3/MaxSil%20Pistons/th_Piston1.jpg (http://i6.photobucket.com/albums/y234/Senpai_Racing/1995%20BMW%20M3/MaxSil%20Pistons/Piston1.jpg)
http://i6.photobucket.com/albums/y234/Senpai_Racing/1995%20BMW%20M3/MaxSil%20Pistons/th_Piston2.jpg (http://i6.photobucket.com/albums/y234/Senpai_Racing/1995%20BMW%20M3/MaxSil%20Pistons/Piston2.jpg)

[EstorilRoc3060]

Can someone teach me more about Over-boring our engines. I'm thinking about doing this later down the road along with blueprinting and other engine build up work. I tried to understand the above conversation, but really couldn't follow, any one help me out?

[EastBayBimmer]

Over boring an engine refers to when a machine shop takes the block and increases the diameter of the cylinder. It gives a fresh cylinder wall, and depending on how much material is removed, increases displacement. The correct pistons must be matched with the amount over bored.

[EstorilRoc3060]

Haha, yea I knew that, I guess my question is more directed at the correct choice of pistons to install

[conway]

Mahle makes great pistons. Some of the best.