Need advice on piston / rod orientation

[Mad_Trbo]

I am rebuilding and I was reading about the orientation of the piston / pin / rod and it appears that for a clockwise rotating assembly you want the rod located to the right on the pinn instead of the center. I believe this is defined as the thrust area, the literature I was reading didn't really do a good job explaining why you build it this way and I am sure I am misunderstanding what they mean by the right.

From what I understand you are suppossed to reference a dot / arrow or the word front. From there when mounting the piston on the rod and rod on crank the arrow should be facing the front of the block, right? How should the rod be oriented on the pin? Center, right, left and if you are going to either of these is there a measurement you should be making for final placement? I am going to be using wiseco pistons and I don't even believe they have the reference point at least not on the top.

One final question how many of you have used heat on the rod end to get the pin in. If so is this a bad idea and you should just go ahead and have it pressed? And how did you heat the small rod end?

 

[Blown&Injected]

Yes the notch or arrow points to the front. The rods have dots and the three on one bank get pointed towards the front and on the other side the dots on the rods face the other way - do not recall which side is front .

I have never pressed the pins in the rods but I have seen tools that heat the small end so that the pin presses in easier. So it would seem to be an acceptable procedure. It looks like the pin needs to be centered or it can stick out beyond the side of the piston.

 

[Mad_Trbo]

Yes the notch or arrow points to the front. The rods have dots and the three on one bank get pointed towards the front and on the other side the dots on the rods face the other way - do not recall which side is front .

I have never pressed the pins in the rods but I have seen tools that heat the small end so that the pin presses in easier. So it would seem to be an acceptable procedure. It looks like the pin needs to be centered or it can stick out beyond the side of the piston.

Thanks for the information and I agree the pin itself has to be centered within the piston, else you have an issue with the piston bore. But when looking at the stock set up the rod itself is not centered on the pin it seems to be offset to the left or right.

 

[Mad_Trbo]

Off center block

Ok, so he board is doing a good job of letting me figure this all out and obviously I am slow. But I think I have finally figured out what an off center block vs an on center block is. It all has to do with the way the piston bores line up with the crank journals used to drive the pistons.

What I need to know is how do you determine what the clearance is for the offset, is this listed in the service manual and secondly how do you know which direction the offset should be set in. In other words is the smaller side of the offset supposed to face the back of the block or the front of the block. I know this has something to do with the direction the motor turns and the thrust surfaces.

 

[Squid4life]

I may be all wrong here but when you hang the pistons on the rods, you center the rod on the wristpin, which is also centered into the piston. If I remember right, with the piston/rod centered when you install the piston into the cylinder it is pretty much centered. I don't remember ever "offsetting" the piston/pin/rod.