Originally Posted by flare1967
Hello i bought an engine 307 bare block and i need help putting the pistons in order. Does it matter which one goes in what cylinder hole. The bottom rods have numbers but i dont know the order they go in. And does anyone know the torque specs for the crankshaft and rods?
The rods are numbed for the cylinder they're intended to be installed with. The 307 is 1-3-5-7 on the drivers side and 2-4-6-8 on the passenger. The rods are positioned so that the largest chamfer on the big end faces to the outside of their journal. This will put the numbers facing down so you can see them when the rods are in the crank as installed in the block. In that position from front to rear of the engine you will read them as 1,2 paired on journal 1; 3,4 paired on journal 2; 5,6 paired on journal 3; and 7,8 paired on journal 4.
The pistons have a direction because the pin is offset for thrust, this is usually indicated by a notch or arrow that will always point to the front of the engine when installed.
So alignment and installation requires that two minimum conditions be met, that the piston's direction mark be facing forward and the largest chamfer on the rod's big end be facing to the outside of the journal it rides on.