john.tempest

Hey Everyone,

Well I have finally made the decision after tons of research to build my LQ4 rather then my LM7. The 6.0 just seems like a bit more fun for me and not having to pay machining fees to bore the 5.3 to a 5.7 makes even more sense in my eyes.

Anyhow, I am talking with my builder and he is recommending that I go with MAHLE forged pistons. I have seen a lot of these pistons in import cars, but have seen a lot of mixed reviews on the internet for these pistons. I know there is a lot of he said she said crap out there so I wanted to get some feedback from people who have run these pistons in an application similar to mine. Will be going with forged pistons and connecting rods, will be using the stock crank. Probably max of 12 psi through the car for now and I will be running ported 243 heads. Goal is about 500 ish RWHP

Thanks!!

KCS

iTrader: (20)

They're nice pistons, but they're usually made from 4032 alloy rather than the 2618 alloy. Some people prefer the 2618 alloy in power adder applications because it is "softer" and will take a beating better than the 4032 would. However, the 2618 alloy expands more and requires looser piston to wall clearance. If you don't run it lean or overboost it, either one should be fine.

conan

iTrader: (5)

I'm running a Mahle piston in my 383ci with 8#'s of boost. Haven't had any problems with them. I also ran them in a 347ci with 10-11 #'s of boost, no problem there either. Like KCS said, don't run it lean and you'll be fine. You can kill any piston if your tune sucks.

slow trap

iTrader: (22)

you will wind up upping the boost before long because you will wind up wanting more power. we all do. get the 2618.

john.tempest

So, does the looser fitting piston mean that I am more likely to get blow-by or is this more influenced by the rings? Sorry this is the first motor I have kind of planned and built myself, and just want to make sure I am doing it right.

If not Mahle pistons whom should I look into to get the proper piston material? Also, anybody suggest a good vendor for this whom could offer advice?

As far as the tune is concerned, will be running a Holley EFI system and off to a actual tuner. They are few and far between here in Canada.

Thank-you!

slow trap

iTrader: (22)

i would check with some of the vendors for a rod/piston combo. any of the piston manufacturers that have a 2618 material piston should hold up well. something like the eagle/compstar rods will hold up.if you are not dead set on building your own motor you can probably sell what you got and buy a forged shortblock for not much more than it costs for parts.there is a forged 5.3 for sale bored out to 5.7 with arp main/head studs in for sale section for $ 2500 still new.

Fry_

The positive of running a 4032 alloy piston is the motor will last over 3 times longer if it's built correctly and you don't blow it up first. That's the reason oem's use 4032 pistons when they build a motor with forged pistons.

ND2RACE

I used them in my LQ4 build, it's just my opinion that being a fun street car didn't neccesitate race pistons. If I was building an all out race motor I'd have went with Weisco or Diamond pistons. My engine has had countless bottles of nitrous run through it anywhere from 150-200 making around 550-600 at the tire, and still runs great at about 20k miles. I wouldn't hesitate to run Mahle pistons in a street car.

Coonass350

iTrader: (19)

I had bought all the components for a forged 347ci using mahle forged pistons, stock crank, and forged Scat I beam rods. Sold it to a guy with an FRC C5. He had it assembled and topped it off with a D1SC(i think..possibly different blower) anyways..it made 800+to the wheels. That was two years ago..its still kicking ��