My machinist called today and said he had a problem with my pistons...

I had given him a set of .060 over Sealed Power pistons for the Hpak motor...It seems I have 4 in the box with a 1/2" from the rib to the edge of the skirt that are lighter in color and have a different "stamp" on the face...and two that are darker in color and are 1" from the skirt to the rib
(and heavier)....My machinist says he's been seeing this with Fed Mog...that they have a few NOS old pistons on the shelf then throw those in a box with a few of the "new ones" from Thailand...

He's checking to see if a local wholesaler might have a set on the shelf that is matched...or 4 of one or 2 of the other "stamped" number.

Guess I'll check the contents of my packages a bit closer this next time around...

-D.Idiot

If they have the same part number, they MUST all be the same.....



Right?

_________________
Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Not always...
I see this a lot with the long rod builds, using the off-the-shelf 2.2 pistons.
Those are always boxed in sets of 4... so you basically need 2 sets.
I mostly see big weight differences but also other casting and machining changes.
(I look for the "year code" cast into the underside to help match sets)

The good news, usually the important measurements are in tolerance.
(Compression height, diameter, pin bore and ring groove size and placement)
The bad news... a lot of extra re-balancing time getting all the weights the same.
DD