Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
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When do you use Full floating pistons (bushed wrist pin) vs. pressed wrist pin? What are the trade-offs for one design over the other? Does it depend on the piston or the engine output or what?
They both work the same. Full floating just allows anyone to install a piston on a con rod. Pressed fit pistons need the small end of the rod heated up before pressing in the wrist pin. My big block just got the pins pressed in. The rod ends have a blue tint to them now from being heated up so we;re not talking about a simple propane torch to heat them up.
A backyard mechanic can install full floating pistons with no special tools except a snap ring pliers.
87 IROC-Z Pro ET Bracket Race Car
383 stroker (carbed) with double hump cast iron heads and pump gas
454 Big Block buildup now in progress for the 2001 racing season
Best results before the 383 blew up
Best ET on a time slip: 11.857 altitude corrected to 11.163
Best MPH on a time slip: 117.87 altitude corrected to 126.10
Best 60 foot: 1.662
Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association
Floaters are considered better for high RPM use and other heavy-duty situations because the pin can rotate, so the wear on it is more evenly distributed. There also may be slightly less friction. Plus like Stephen said it makes it easier to tear the motor down and replace parts if necessary, like between runs or whatever.
The down sides include: they're noisier, because that's one more set of things that can rattle around; and the little Spirolox rings that they use aren't the most reliable things in the world, especially when re-used. Somebody used to make Teflon buttons that you could use with any pistons since they don't require the groove for the Spirolox which would otherwise have to be cut, but I haven't seen any of them for a while. Also, this requires some method of oiling the small end of the rod a little better than it would otherwise be oiled, to prevent the floating system from galling.
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"So many Mustangs, so little time..."
Sorry for bumping up a really old thread, but I thought it would be better to ask here instead of making a new thread.
Is it possible to use a piston with floating style wrist pin on stock Chevy SBC connecting rods? As far as I know the stock piston/rod is a press-fit style.
