HyperBaja

Ive read a bit about floating piston pins (i think???) cant remember right, can someone fill me in on what this is, how it is done, what type of gains, etc.

Thanks
Tommy

blown1500

Most OEM piston pins are "pressed" into the rod and move freely in the piston. Most are really installed by heating the small end of the rod and pushing the pin through. When it cools, it is very tight.
Floating pins are not pressed in. The rod is clearanced so the pin can be installed easily by hand. Locks are installed, usually in the piston to hold the pin in place.
The biggest advantage I know of for pressed pins is the manufactureres like them.
The floating pin has the advavtage of ease of assembly/dissassembly (except for removing those locks ) and gives the pin one more place to move in a high load situation.
If you are doing stock rebuild, don't bother changing. If you are going to aftermarket rods, most come with floating pins.
I prefer floating when practical (most of the time we use floating pins)
Hope this helps. Need more, post. There is a lot more to this, but these are the basics.

Crazyhorse

Yup, what he said. Stock full-floaters are tinned at the small end so the pin isn't floating directly on the steel, but reworked or aftermarket rods have bronze bushings in the small end. Some guys use snap rings for pin retainment but I prefer double spiralocks.

HOTROD2

I was told by a NASCAR engine builder that a full floating pin needs more oil which it only gets at higher rpm (oil splash) so if you idle the engine for long periods of time the pins can run dry and start to heat up and stick in the rod. I have not had this problem with mine, so far, but was warned about this. Any of you engine guys know more???

HyperBaja

So basically it is for disassembly? I thought it would be something more?

blown1500

I know several NASCAR engine builders and machinists. NONE OF THEM THINK YOU WILL HAVE AN OILING PROBLEM!!!! Just the opposit is usually true. You have one more place for the oil to get to to reduce the possibility of pin oiling problems.
Crazyhorse has the correct idea. Many manufacturers of performance cars use floating pins. Mercedes, BMW, GM on the LS7, L88, many more without problems.
Also, most piston manufacturers now include Spirolocks with the pistons. The don't come out. "Snap rings" can come out and that is a terrible mess to clean up!!!
HyperBaja, floating pins are easier to assemble and dissassemble, if you can get the spirolocks out, but the safety factor of the floating pins is the reason to use them. If the rod is preped correctly, they are the best idea I know of.
Have a Great Day!!!!!

HOTROD2

blown1500, Sorry for passing on something I was told, I didn't mean to step on your NASCAR buddies program. and I only was asking if any of you "BIG TIME" engine guys knew any differant, and now I know that you do!!! I have always woundered why its hard to be part of this site, and now know that too!!!

Iggy

I saw, some place, where the machinist drilled a small hole in the big end of the rod and it was aimed at the top of the piston. It was done for two reasons, one to cool the piston and the other was to lube the pin.
Another had drilled up through the center of the rod to the small end to provide pressurized oil to the pin.
I believe this was done on NASCAR engines.

blown1500

HOTROD2, I havn't had my Prozac for about a week now, soory to yell at you. I know some NASCAR engine builders who know less than almost anyone on this board. The got their job because of who they know, not what they know!! I hate that. I also hate all the misinformation out there. I have learned a lot from this board and I thank you guys
Iggy, the small hole in the end of the rod small end is for oil to fall into that is splashing around under the piston but it does nothing to cool the piston unless pressure oiled. They do commonly drill a small hole through the rod to carry oil to the wrist pin from the crank. If you run low pressure or vacuum in your crankcase, you need them too.