RCU Forums - View Single Post - Internal differences between .60FSR and .61FSR?

11-21-2008 | 12:36 AM

#42

DarZeelon

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From: Rosh-HaAyin, ISRAEL

RE: Internal differences between .60FSR and .61FSR?

Quote:

ORIGINAL: Roguedog

...I understand about the stroke length. If the pin boss on the 61SX piston is say 1.5mm higher than a 61 FSR/SFN piston boss and the SF/RF/hanno rod was 1.5mm larger that the FSR/SFN rod, wouldn't that place the SX piston in the right location?

That is correct, Bryan.

It is more familiar in full size engines, BTW.

If you were ever interested in hot-rodding a Small Block Chevy engine, for instance;

The 350 cid engine has the standard rod length of 5.7" center-to-center.

An effective upgrade is to use longer rods of 6.0", and special pistons that have a 0.3" lower compression height.

As you guessed, this bring the piston to the same 'deck height' as before.

The advantages are; decreased angular forces (toward the side of the cylinder) on the piston and a lower rate of acceleration of the piston at TDC (ultimately allowing a higher RPM limit).

The pistons have to make do with less room for the three rings and the engine needs to be rebalanced, since the longer steel con-rods are heavier...

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