Brian, Where did you get all of this info?

 

Brian is the crowned King of cut'n'paste

 

That was just off the top of my head....

 

Brian, excellent information.

I'd like to argue some of those points if you won't take offense.

I think it would shock some people if we could plug in some piston weights and engine speeds to illustrate the point about accelleration forces. The magnitude of the forces involved will boggle your mind. Use good rod bolts and torque them properly. Don't overspeed your engine. Keep the parts light if you're gonna jazz the motor.

 

Lot's more stuff to argue about here. These guys are more Chevy oriented so some of the info may not apply to Fords the same way.

Engine tech
http://www.grapeaperacing.com/GrapeApeRacing/tech/

 

Thanks for the link. It helped put the information into perspective. No sources of information are cited and I don't believe everything that's been said there.

The way I see it, good ol' Smokey Yunick popularized the idea that longer rods are better. But ol' Smokey offered a muddled explanation of exactly why. I've pondered the subject for quite a while and I've gotten other information, including dyno tests, that don't support the theory that long rods make an important difference. In fact, the information I have says just the opposite; shorter rods make more power on the dyno.

I have a research report that tested rod lengths. This was done with an air-cooled Volkswagen engine because it could be reconfigured to factor out the effects of piston height and other factors. Result; no improvement in power with longer rods.

I also have a magazine article that goes through an engine build-up, and as an afterthought, they reassembled the engine with shorter rods to prove that the longer rods are better. I'll give them credit for having the guts to report the facts, but they tried to explain away the fact that the shorter rod engine made more power. What's worse is that they didn't do any tuning to optimize for short rods, they just changed rods and pistons and made more power! Then they dismissed the results. Incredible.

 

No such thing as an ideal combination. The info I provided was mainly to illustrate the change and effect. Personally I favor slightly longer rods than stock, but only if it can be done at a minor cost. There's no point in spending a lot of money for such minor improvements.

 

Brian, I concur. I would not spend money to alter rod length. But if I had a choice, I would go with shorter rods. Thanks again for posting the info and the link.