VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 piston skirt slot

Which way is the correct way to mount the piston on the rod on a 30? Does the skirt slot face the cam side?

The slot on aluminum pistons is placed on tthe NON-THRUST side which is the camsaft side I believe.

Umm... Gene is correct that the slot always goes to the "non-thrust" side, but I think the camshaft side of a Chev six is the "thrust" side, correct? That would mean the slot will go to the left side of the engine as viewed from the rear, opposite the camshaft.
Looking at the front of the engine, the crank turns clockwise of course, so on the down stroke the bottom end of the rod is going down on the side opposite the camshaft, with it's angularity throwing the thrust on the camshaft side of the cylinder.
Therefore piston slots always go to the left side as viewed from the rear.

I have always considered the "non-thrust side" as the cam side. As the crank turns the crankpin being to the right of center is pushed downward on the power stroke creating the "thrust" .As the crank turns clockwise the crankpin is always coming up on the cam side on either compression or exhaust and neither creates "thrust".

Don't think so.
You'll always find the most wear and deepest ring groove on the camshaft side of a Chev six... because it is the "thrust" side.
The highest pressures are of course during the power stroke. As the crank pin goes down on the side opposite of the camshaft on the power stroke the angle of the rod throws the thrust to the camshaft side of the cylinder.
Place one end of a ruler on the top of your desk with the ruler straight up. Now angle the top over about 30 degrees to the left as if it were the rod viewed from the front during the power stroke.. Now hold the bottom steady and push straight down (perpendicular to the top surface of the desk) on the top end of the ruler. Remember to push "straight down" as if your hand were the piston pushing down in a straight up and down cylinder. Which way does the top of the ruler try to go?

Easy enough to get mixed up but you can verify with a visit to installation instructions on piston manufacturer websites if you like.
Some pistons will tolerate being installed either way.
Slotted aluminum probably will not. Particularly if the slot is open at the bottom as some Californian Chevy six hotrodders of the early fifties recommended.

I really want to thank all of you. Very helpful information. You guys are great.

Thanks for the lesson Ole. I'll keep my fingers crossed that I paid attention to the instructions when I built my 235 which I have yet to start. If I remember correctly the instructions referred to the slot position so as long as I followed the instructions it should be good to go.

If genuine Chevrolet aluaminum pistons were used in your 235 there is no T slot....However the 1954 and up (and 1953 replacements) had the wrist pin off set slsightly to one side to prevent cold engine piston slap. Was important to have the off set on the correct side. I t goes to the thrust side which is the camshaft side according to the shop manual.

I believe they were sealed power purchased from Patricks shortly before they closed up. My friend that helped me (or I him) worked for a restoration shop and was a mechanic most of his life so I am confident it is together correctly.

Glad to help. And glad to be here as I learned something new about installing pistons with offset pins that I didn't know!

I would ask the piston supplier if you are installing new. I had contacted my supplier and they indicated the slot to face the camshaft.

Don't ask the piston supplier. Ask the piston manufacturer.

My point is don't take anyones word for it. Yes check with whomever made the pistons.