[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!

How many times does it need to be said the engineers only put that offset there so that people on a cold stop wouldn't hear piston slap. You do understand that with that offset the piston and crank journal are not at TDC at the same time?

Stan

[JSchmitz]

Originally Posted by Stan Weiss

How many times does it need to be said the engineers only put that offset there so that people on a cold stop wouldn't hear piston slap. You do understand that with that offset the piston and crank journal are not at TDC at the same time?

Stan

Yes I think I understand it pretty well. Piston slap is bad. It causing ring wear, sounds bad, etc. The offset is there help eliminate this. Are you saying that his knock isn't from improper assembly?

I know that my dad owned a 1969 Chevy pickup. He had the engine rebuilt. The guy put the pistons in backward. Guess what, it had a strange knock.

[Stan Weiss]

Originally Posted by JSchmitz

Yes I think I understand it pretty well. Piston slap is bad. It causing ring wear, sounds bad, etc. The offset is there help eliminate this. Are you saying that his knock isn't from improper assembly?

I know that my dad owned a 1969 Chevy pickup. He had the engine rebuilt. The guy put the pistons in backward. Guess what, it had a strange knock.

So does this mean you will never run an after market piston that doesn't have any offset?

Stan

[Shiny]

As a spectator (or maybe in this case an observer of a spectacle), gtofreek's explanation of offset was the most helpful for me:

https://forums.maxperformanceinc.com...6&postcount=24

[rick38]

I am building a another 455 for my 66 gto 4 speed 3.31 gear car .


I have a 455 .030 over with flat top speed pro pistons and a melling 041 copy cam I have a set of mild ported 6x-8 with heat risers blocked

the heads are about 101 cc now. My plan was to mill about .040 to get about 95 cc What do you folks think ?

Any input would be appreciated Rick

[Jay S]

Originally Posted by rick38

I am building a another 455 for my 66 gto 4 speed 3.31 gear car .


I have a 455 .030 over with flat top speed pro pistons and a melling 041 copy cam I have a set of mild ported 6x-8 with heat risers blocked

the heads are about 101 cc now. My plan was to mill about .040 to get about 95 cc What do you folks think ?

Any input would be appreciated Rick

Start your own thread if you want something answered, or it will be lost in this long thread that is going in circles.

[Dragncar]

Originally Posted by rick38

I am building a another 455 for my 66 gto 4 speed 3.31 gear car .


I have a 455 .030 over with flat top speed pro pistons and a melling 041 copy cam I have a set of mild ported 6x-8 with heat risers blocked

the heads are about 101 cc now. My plan was to mill about .040 to get about 95 cc What do you folks think ?

Any input would be appreciated Rick

You will be fine. But there is a bunch of other stuff to talk about.
Start another thread and we can talk about your build in more detail.

[rick38]

Thanks Perfect

[JSchmitz]

Originally Posted by Stan Weiss

So does this mean you will never run an after market piston that doesn't have any offset?

Stan

No, I'll order custom pistons with the offset. Then I'll install the backwards to break the laws of physics.