[Stan Weiss]

Originally Posted by Tom Vaught

I will try on this deal:

1) All of the pistons have a notch that should face the front of the engine no matter which side it is installed on.

2) Pistons with "offsets" are made to eliminate "piston slap" noise

3) Looking at the engine from the flywheel side, the passenger side bank is on the right. The Driver's side bank is on the left.

4) The normal firing order for a pontiac is 18436572. If we move that
one cylinder event forward the numbers would be 21843657, ok?

5) We want to talk about the #2 piston and the #1 piston for our discussion.

6) Wrist pin offset is related to rotation. The offset is designed to direct the angular resistance of the rod on the power stroke more closely to the center of the piston as the rod moves through the stroke. Usually, the piston pin is offset slightly toward the major thrust face to reduce. piston slap against the cylinder wall.

7) With the "notch" facing forward on the #2 piston and the piston having a slight offset towards the major thrust, it will be happy.

8) With the "notch" facing forward on the #1 piston and the piston having a slight offset towards the major thrust, it will be happy. The major thrust side of the cylinder bore will always be on the left side of the cylinder (drivers side) when looking from the flywheel.

Does that make it clear now?

Connecting rods:

1) Even though we call the 1st cylinder on the drivers bank the #1 cylinder, the #2 cylinder is actually farther forward.

2) Lay a crankshaft on the ground with the flywheel flange closest to you. Flywheel flange at 6:00 and balancer snout at 12:00

3) Rotate the first rod journal on the crankshaft so it faces toward 3:00 and visualize two rods installed on the rod journal.

4) The rod closest to the 12:00 position will be the rod for the #2 cylinder and the rod chamfer will face 12:00 on the crank.

5) The second rod on that rod journal will be the #1 rod journal and that rod's chamfer will be facing 6:00

6) The rods are oriented that way for two reasons:
a) The chamfer will clear the crankshaft radius ground into the crankshaft
b) The Bearing tangs will face upward as the crankshaft rotates in the block. Old factory Pontiac rods had oil squirters on the tang side of the rods to cool the piston bottoms and lubricate the camshaft and cylinder walls.

So to answer your questions:

Piston notches to the front
Rod tangs always up and hopefully rod chamfers ground correctly.

Tom V.

ps The first set of piston pictures is correct. The second set is wrong.

Exactly!!!!!

Stan