PIstons and rules

#1

Been reading through posts from 3 years ago and can’t seem to find the answer.

Pistons. What is a legal replacement? Only ones I can find are the forged Mahle, and MaxSil pistons. Neither of which appear to follow the rules.

#2

Call Bimmerparts and order the .5mm oversize mahle pistons. They were about 500 or 550 when I bought them last year.

http://www.bimmerparts.com/

#3

I would rather not order a heavier piston, but then again I don’t have specs on the stock ones and the range from the factory on weight. Considering the rules state they must be the same weight, it would seem even a forged piston is illegal.

#4

I don’t know where you’re finding forged Mahle pistons. The ones bimmerparts sell are cast and I’m quite sure that they are the oem pistons.

#5

Yup, my bad those appear to be the stockers. Did not know the stock cast pistons were made by Mahle. On top of that I couldn’t make sens of why they were more expensive than the MaxSil Pistons at Bimmerworld.

#6

Pistons must be all dimensions as stock. MaxSil is not legal as they are coated on the skirts. CB

#7

I thought that was the case, thanks Chuck.

Are there any other options?

#8

Forged pistons are only lighter if they are designed to be lighter. Someone around here makes forged SpecE30 pistons, I’ve seen them on at least one website. If that’s what you want, look around a bit and you’ll find them.

#9

Yeah, typically I have run into the forged versions that are a bit heavier than the cast versions just for strength, but I would have no use for those. Just seems like throwing money away.

Was just curious if there are really any other options that are cheaper than the stock Mahle ones.

#10

VAC has forged but as with Mahle, they are special order. I had to use them on a motor build after waiting for 4 months on Mahle. Seems that my 6 piston order does not mean jack shit when NASCAR is ordering thousands. Chuck

#11

I was really becoming concerned about this, and then I made some homemade roasted salsa and had a rum and coke.

#12

That’s the spirit!

#13

Chris at Bimmerparts.com can get you .020" over Mahle pistons very quickly at $540 for the set. IMO, this is the best piston option that doesn’t break the bank as the VAC forged pistons are special order and near three times the price. For rings, I prefer cast iron with moly inlays that Metric Mechanic offers. They can also get them quickly.

#14

That’s the spirit![/quote]

You guys need to stay at the track more often so we can sit down for some…drink.

#15

The VAC forged (CP) are 1150 and can be ordered in any configuration…including bone stock. They are an upgrade alternative to the stock Mahle.

What don’t y’all understand about piston coatings being illegal?

Stock Mahle pistons will work fine in these motors…you absolutely do not want anything cheaper…you want your motor to last!!! Chuck

#16

Oh I understand about the coatings being illegal. It just looked like there was only one other option and at the time I thought it was a forged piston.

I’m just used to being able to order a set of 8 pistons for a small block and paying about $300. BMWS…

#17

Pistons for a m20 engine?
I purchase them day-in-day out for $300.
Purchase wrecked car for engine core. Then the body panels, suspension bits and pieces are free.

RP

#18

[quote=“Patton” post=67642]Pistons for a m20 engine?
I purchase them day-in-day out for $300.
Purchase wrecked car for engine core. Then the body panels, suspension bits and pieces are free.

RP[/quote]

Will stipulate…new pistons.

#19

Robert, it’s difficult to find oversize pistons that way:sick: Chuck