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Discussion Starter #1
Do they have to match or what???

I really have no clue of what can be done..

Since I'm on a budget I'm thinking about getting pistons&rods and just grinding my old crank.:( but I dont know what kind..
 

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Don't know if I completely understand your question, but I'll take a shot. Rods can either be press fit, or "flotated" which means that the pin will slide through the rod. Normally flotated rods have bushings in them. Supposedly floated is better, but I'm not really sure why.

From what I've seen, the pistons are always floated (but surely somebody will prove me wrong) and typical stock applications use the press fit rod, meaning that replacement pistons are manufactured with this in mind. If you want to run a floated rod you need to have snap-ring (or other style ring) grooves in the pin bore of the piston in order to keep the pin from moving over and rubbing on the cylinder wall. My pistons have this ring, but I'm using the stock style press fit rod so I just threw the rings away.

Hopefully this helps.
 

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Discussion Starter #3
ttt

Any more input, anybody???
 

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Floating pistons pins reduce the amount of friction that is created by rotating the pins. When you're running lots of RPMs, it's a good idea (lots=over 6500). It's probably worth a few HP (more than 2, less than 10) at the top end.

If you get floating rods, make sure they're bushed, not just honed.

-Mike
 

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If using a press fit rod, can I still use a bushed piston? I would think that the piston would still have the clearance to rotate on the pin, but the pin would be pressed into and not rotate in the rod, so that one does not need to use the spiro locks?

Or are most all pistons bushed now, and what I described is the way it works?
 
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