Rod length & torque Monday, 22-Jan-01 20:31:16 209.206.4.41 writes: I'm confused. The prevailing theory is that short rods are good for more torque than longer rods. I was under the impression that longer rods are better for low end torque and short rods are better for high RPM. Longer rod length should produce longer piston travel which would result in more torque. Is this correct? K-Ghia Ken Swain

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Replies:

They way i understand it.....>>> ( James2) (22-Jan-01 21:16:31)

Ken in addition to James reply I thought I might mention that you will also increase the overall width of your engine using longer rods. Something to think about if you are putting it into a Bug or Ghia. (n/t) (Ryan Brill) (22-Jan-01 21:49:42)

Re: Rod length & torque (Jack Sacchette) (23-Jan-01 00:27:18)

I agree with Big Daddy (n/t) (Dave Perkins) (23-Jan-01 00:41:55)

jack, you got mail (n/t) (Jimmy) (23-Jan-01 02:05:34)

Re: Rod length & torque (K-Ghia) (23-Jan-01 21:46:24)

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First off, piston travel is determined by the stroke. The rod length doesn't make the piston travel any more or any less.

The shorter rod makes more torque because it pulls the piston down much faster after TDC. This draws in more Air. However at higher RPM, cylinder filling benifets by the more "dwell" that a longer rod has, also it gives the combustion process more time to burn. So a long rod engine will make more torque at higher RPMs.

James2

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The longer the better. Longer rod bearing life and more power PERIOD.

Jack Sacchette

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Thanks for the input gentlemen! The wider engine isn't an issue because the pistons I have have the wristpin up near the oil ring to compensate for the longer rod length. Thanks again. Ken

K-Ghia