Yet another piston question

[glhman]

Read the threads about cast vs forged, but couldn't get the answer for my question. I'm building a '89 T2 motor for my '86 GLH. Going to see 15-16 PSI max, since it will still be my daily driver. Need it to be reliable, but I'm not sitting on a pile of money either . Going to be basically a stock motor except the computer, just going to port match and clean up the combustion chamber. Maybe going to 3" exhaust at some point, but thats about it. Will be running an intercooler, and will probably run a drip-style alky injection setup. The question is do I need forged pistons? Or can I get away with cast ones?

[Turbofreak]

on a 2.2L, the cast mahles will be ok, just keep it safe when tuning it and put a wideband on it to monitor O2 content after slowly creeping up on 15-16psi of boost...

I have heard as much as 22psi on 2.2L cast mahles will hold if not too lean!!!

not the same story on the cast mahles for the 2.5L.... ;-(

IF YOU BUY ANY CAST PISTON, MAKE SURE IT IS A MAHLES brand casting.... no others are worth much of a crap....

RYNO

[lametec]

At 16 psi the stock cast pistons should last forever.

Just make sure you feed it good gas.

[DakotaKid]

Quote:

Originally Posted by Turbofreak I have heard as much as 22psi on 2.2L cast mahles will hold if not too lean!!! RYNO

34 psi on my 2.2 Mahles

-Bryan

[glhman]

Always use 91 octane, the highest we can get at 5280' of elevation. How can tell if they are Mahles? I'm buying them from a local shop, they should know, right?

[lametec]

Odds are if they are in stock, they're not Mahles, but Silvolites or something similar.

Make sure you specify that ONLY Mahles will do. They'll have the Mahle logo (or at least the M) cast into them.

[glhman]

I'm assuming that the box says Mahle on it?

[lametec]

Yeah, there's a label on the box.

[mo' parts]

was running 20-22 psi fine for a while. too much timing and weak f. pump cracked two. with proper tuning NO PROBLEM at 15-16.

[turbovanman]

Don't know why you guys specify Malhes, I used Clevite in my 2.5L and they held up to 20,000 km's of abuse, with varying boost from 12-29 psi, towing etc. I broke one after I got stupid with my cam timing. With what you want to run, they will live forever with the right amount of fuel.

[DakotaKid]

Quote:

Originally Posted by turbovanman , they will live forever with the right amount of fuel.

AND cooling!

[lametec]

Quote:

Originally Posted by turbovanman Don't know why you guys specify Malhes

Because they're a good, reasonable piston that nobody has had any special problems with. Why use anything other than what's proven good enough?

[turbovanman]

Quote:

Originally Posted by TrboVan AND cooling!

Yes, agreed.

[glhman]

Quote:

Originally Posted by turbovanman Yes, agreed.

Your mean the head cooling mod? Even on a stock build?

[DakotaKid]

Why not. Cheap and good insurance.