How to tell what type of piston is installed..

[pauly_no_van]

Howdy,

Been reading up on rebuilds and have one with no paperwork.
2.5 all new internals .020" over...
its been spiking to 17 psi for short periods with no issues so far on a stock tune for close to a year.

The question is, is it possible to find out what type of material the Pistons are by how the top looks?
These are laser/pin stamped .050" on top.
The outer-top portion was cut by lathe and the inner part looks to be cast. Definitely not machined. No other markings can be noted.

I am about to put 18+psi on this motor and am getting cold feet after reading about Jasper nightmares and hypereutectic tragedies... Thanks for input!

paul

[cordes]

Post some pics with the top as clean as you can get it and I can do some comparisons on my end. I have a set of TII pistons and some sealed power pistons laying around.

[turbovanman²]

A forged piston on top is nice and shiny, smooth, looks like it was cut by a mill. Underneath, again, it looks beefy and no cross hatch patterns from the casting process. Usually, they don't put the piston size on a forged unit.

[pauly_no_van]

Post some pics with the top as clean as you can get it and I can do some comparisons on my end. I have a set of TII pistons and some sealed power pistons laying around.

Unfortunately I do not have any pics of them from last summer when I went through it/put the head on :(.

Vanman,

they are def. not forged then..

The shortblock was rebuilt in 2001 and then sat with a head on it for 7 years. Previous owner had no paperwork on it and I doubt the builder would remember what was used if I could find him...

paul

[cordes]

Unfortunately I do not have any pics of them from last summer when I went through it/put the head on :(.

Vanman,

they are def. not forged then..

The shortblock was rebuilt in 2001 and then sat with a head on it for 7 years. Previous owner had no paperwork on it and I doubt the builder would remember what was used if I could find him...

paul

I guess it all depends on how much the last guy wanted to spend on it then. The cost for some decent sealed power pistons or even the stock mahles would have been pretty negligible vs. the cheap stuff at the time.

At this point you might as well see what it will do. Careful tuning will keep it alive at around 18PSI regardless of what pistons you have in there IMO. The tougher pistons just provide a safety margin.