3.4 Buick piston question.

[gn69z28]

Customer brings me a set of new pistons to install on rods. He took old pistons off before bringing me rods and new pistons. He didn't mark anything and doesn't remember which way the pistons went on the rods. I've searched online and can't find anything. He says one crank journal has two rods on it. The bearing Tang slots look the same on both sides of the rod. I don't want to install the pistons in the wrong direction. Anyone know which way they go? There is a small hump on one side of the rod. Thanks

[BillK]

FLAT AREA ON BOTTOM OF OEM PISTON PIN BOSS TOWARDS FRONT AND ALL ROD BEARING TANGS TOWARDS LEFT BANK.

That is from the AERA Prosis Software. Personally I dont see how you guys can have a machine shop and not be a member of the AERA.

[peejay]

Curious what you are working on. The only 3.4 I can think of is a Chevy motor and it has extremely split pins to where it looks more like a 4 main straight six.

[dannobee]

From GM SI2000 factory service manual:

<<Important: Ensure that the marks on the piston and connecting rod are aligned the same as when removed. If installing a new piston, ensure that the arrow on top faces towards the front of the engine. If no identification marks were made during disassembly, ensure that the flat area on the bottom of the piston pin skirt is aligned with the small dimple above the connecting rod crankshaft bearing bore. >>

[Baprace]

Just watched a rerun of Mechum <-sp auction last night and one of Scott Brayton's and one of Arie Lyundike's Indy 500 cars were run through the auction, both cars were reported to have 3.4 Buick engines , If I remember correctly Scott Brayton held the track record at 237.??? mph.