60 thou over pistons - limits of cylinder wall strength??

[bazeng]

Guys,

I have a quick question.

Have you or know of somebody who has run 60 thou over pistons?
Also how far did they get - in regards to power / boost etc.
Did they experience any problems?

I'm asking simply because I am using 60thou over in the AMG simply because I had a set of pistons available and also the block was 40 thou over in the past.

I'm not looking to make massive power with the motor since it is a FWD.

I really only want about 300-400 hp at the wheels (FWD).
I think it should be ok, BUT to be safe, I thought I'd ask the question.

I've run 40 thou over before and didn't have a problem except for having a cylinder wall crack but that was because the cylinder was sleeved (just that one).
The others were perfect. That block took about 500 hp @ the wheels.

Does anybody know the thickness of the walls (average??)
Thanks guys.

 

[BoostedAWD91]

I would imagine that's to much to be taken out from what my one machinest said

 

[3rdstrikedsm]

Way to much.
40 thou would scare me

 

[ducttapeguy]

My old engine had 50thou over 9:1 NA pistons and it ran fine until I ran it too lean. I thought they were only 20 thou over until my mechanic took them out and showed me that they were actually 50 thou over.

 

[belize1334]

The G4CS is made of the same iron as a 4g63 with the same cylinder spacing and has a stock bore of 86.5mm (1.5mm bigger than 4g63). If you take that block 0.02 over then you're at 0.08" (80 thou) and people have made 500whp on those setups. Given that, I wouldn't bat an eye at a 60 thou 4g63.

 

[mitsuturbo]

Friends and i have run 3.386 bore (.040' over) in plenty of engines with no ill effects
Are you sure your pistons were not stamped .5, as in 1/2mm? (.020") i suppose your machinist would know enough not to make this mistake, but stranger things have happened.

I have heard of people running 3.406 bore, but never heard back on whether or not they had any issues with it.

 

[bazeng]

I had a spare set of std 2.4L pistons so I decided to use them in a 2.0L block.

They are 60thou for sure.

Well fingers crossed!
I'll let you know how it goes!

 

[Street Surgeon]

You can run em no problem at that power level, not many guys do so around here because blocks are both cheap and plentiful so you usually don't see anyone going over .20 over too often. That being said 60 thousandths isn't a big deal, especially at the 300 to 400hp range!