Mahle piston clearance

Reply Subscribe

Thread Tools

Search this Thread

Oct 27, 2012 | 10:49 AM

mrgwrnch

Thread Starter

Teching In

Joined: Jan 2010

Posts: 36

Likes: 0

Mahle piston clearance

I have a question about a 2002 LS1 engine I'm overhauling for my daily driven '64 Nova. I purchased Mahle LS1314905F04 pistons that are designed for a finished bore size of 3.905" (this varies with application such as type of power adder). My machine shop decided to power hone the bores to 3.9065". The pistons measure approximately 3.902" depending on the temperature. I called Mahle's technical line, they said that was to large, but also said it would run fine. They also said that the engine would be noisey. My question is, who has experienced this and what was your thoughts on this? How noisey will this be?

Thanks in advance.

Oct 27, 2012 | 10:55 AM

bww3588

12 Second Club

iTrader: (49)

Joined: Sep 2005

Posts: 8,139

Likes: 10

From: Chillicothe/Lima, Ohio

.0045 is .00225 piston to wall. You should be fine.

Oct 27, 2012 | 12:07 PM

mrgwrnch

Thread Starter

Teching In

Joined: Jan 2010

Posts: 36

Likes: 0

Thanks for the reply. I understand how you came to the conclusion of .0025", is that how piston to wall clearance is calculated (divided by 2) or is the total sum the industry standard?

Oct 27, 2012 | 12:13 PM

mrgwrnch

Thread Starter

Teching In

Joined: Jan 2010

Posts: 36

Likes: 0

Sorry, meant to say .00225"

Oct 27, 2012 | 03:00 PM

Sales4@Texas-Speed

LS1TECH & Trucks Sponsor

iTrader: (4)

Joined: Jan 2007

Posts: 1,768

Likes: 9

I bet the piston slap in this motor will be the noise they were referring to. That is getting on the large side of piston to bore clearance, but as Mahle said it should run fine. The extra piston to bore will allow the piston to rock just slightly more causing the extra noise.

Oct 27, 2012 | 06:20 PM

mrgwrnch

Thread Starter

Teching In

Joined: Jan 2010

Posts: 36

Likes: 0

As a side note, when I spoke John @ Mahle, he was kind enough to swap out my untouched pistons for yhe next oversize at no charge. Now they have a customer for life.