[Stan Weiss]

Originally Posted by JSchmitz

I would say that the piston installation didn't break any laws of physics. They are merely complying with the laws. The laws dictate that the pressures and angles act on the pistons in a certain manner. The engineers, that designed the pistons, understood this better than anyone in this discussion. They designed an offset to minimize unwanted movements of the pistons and maximize efficiency. Choosing to go against this is most likely causing the noises in this engine. But he wants to blame it on the moon, stars, and everything else. I say, GOOD LUCK!

If that is the case then why does ever Pontiac engine from a 326 ci to a 455 ci having different bore size and strokes all had the same 0.063" offset? (Based on the information I have)

Stan

[JSchmitz]

Originally Posted by Stan Weiss

If that is the case then why does ever Pontiac engine from a 326 ci to a 455 ci having different bore size and strokes all had the same 0.063" offset? (Based on the information I have)

Stan

That's a good question. Maybe they chose a standard offset that minimized piston rocking and thrust loads on the piston. Maybe it's the maximum that they could justify. Maybe it just works well for all. Maybe the guy was mental. LOL

[242177P]

Originally Posted by Stan Weiss

If that is the case then why does ever Pontiac engine from a 326 ci to a 455 ci having different bore size and strokes all had the same 0.063" offset? (Based on the information I have)

96,946 GTOs built in '66. Eight pistons each... 775,568.
Pistons were mass produced, fixed offset makes sense.
455SD was already receiving extra attention because of
the rods, 326 just needed a slug to fill a hole.

[steve25]

Something related to piston noise is being overlooked here I think.

Prior to the the first 400 motor in 67 Pontiac pistons where fully round and in my mind other the the issue of having the rods facing the wrong way on the crank if you had a piston in a motor the wrong way I don’t think you would hear much added noise when cold.

Now let’s look at the 350s, 400s, 428s and the 455s with there inventive usage of a Cam ground piston.

Now if you reversed these pistons, yes to me you would be in for a good amount of cold slap noise, and along with the noise comes ware.

Just some food for thought here.

[Kenth]

Originally Posted by steve25

Something related to piston noise is being overlooked here I think.

Prior to the the first 400 motor in 67 Pontiac pistons where fully round and in my mind other the the issue of having the rods facing the wrong way on the crank if you had a piston in a motor the wrong way I don’t think you would hear much added noise when cold.

Now let’s look at the 350s, 400s, 428s and the 455s with there inventive usage of a Cam ground piston.

Now if you reversed these pistons, yes to me you would be in for a good amount of cold slap noise, and along with the noise comes ware.

Just some food for thought here.

This is from the 1966 Tempest Shop Manual:

[MatthewKlein]

Originally Posted by Stan Weiss

If that is the case then why does ever Pontiac engine from a 326 ci to a 455 ci having different bore size and strokes all had the same 0.063" offset? (Based on the information I have)

Stan

Things have progressed to the point I prefer this thread to be more comedy oriented and less well thought information

In the beginning I had genuine concern but it has evaporated