ok, i understand it is the length of the rod...but is there anything gained or lost by using a 6.125 instead of a 6.098?

why do they make pistons to accommodate both?

the reason i ask is because i have forged pistons that are going into a forged 347 i am building and i need 6.125 so the question popped in my head.

Thanks
Louie

 

There was a discussion on this a while back. I wish I could remember exactly what the reasoning was, but I believe the shorter rod is the best route. I forget why though. Try doing a search in the advanced section.

 

I have allways been told the longer rod you can get in there the better. The longer rod will allow the piston to dwell at TDC slightly longer allowing more air/fuel to be pulled into the chamber. This action also is supposed to put less stress on the cylender walls and the rod/piston itself.

This is what I have been told years ago, does it hold water?

 

The longer rod you can get in the better mostly, there are always exceptions though. The major benefit to a long rod is that it keeps piston speed lower compared to a short rod at the same time. I also forgot to mention there is less side loading on the rod with a longer rod, Jeremiah touched on that slightly.

 

i always believed that the longer rod did make the piston dwell at tdc for a degree or two at most i believe. But not to pull in air/fuel mixture but the combustion pressure will be slightly higher before the piston is pushed back down on power stroke thus creating some more HP. just what i believe. but rod length is something that should be considered in the whole package of what you want to do with this engine.

just my two cents

Ryan

 

Take a look at this:

http://victorylibrary.com/mopar/rod-tech-c.htm

It tells you a lot on the rod length subject.

I would rather use a shorter rod, if that is what it take to make room for the piston rings, oil ring in particular.
I am talking street DD aplication here.


Br//