pressing pistons to rods

I'm guessing no but before I learn the hard way I'm gonna ask. When pressing the pistons on to their rods is that any need to lubricate first? I would think no because it would stick better that way but once again I would hate to get them on and find out otherwise. Thanks

Warm the pistons in your wife's or g/f's oven to about 150 deg. or so. (Tell her its a new and exotic style of cookware.) Throw the piston pins in the freezer for a while.
The thermal difference between the two will really help installation.

Agreed. When a shop does it, they heat the small end of the rod pretty hot. I don't know how hot, but the pin slips right in like a zero fit.

Don't physically use a press to put them in, you'll damage the whole works

Your kidding so I heat it up to 150 then put it in the freezer till its cool enough to touch and just slide it in? That's unreal I'm glad I asked first because that is something I would never have thought of.

Yeap. Press-in pins refers more to the clearances involved more than the method used to install them. If you install them with a shop press you'll most likely cause stress fractures in the rod and failure will happen soon after. The secret is not to stretch the rod metal by pressing it in, but to let the metal relax around the pin and heat is what most commonly does the trick.

So, you heat the rod to 150 and put the pins in the freezer. The pins contract and the rods expand. Assemble them and let them get to room temperature and they'll be press-fit without the pressing.

Ok what do you do when you've heated up the rods and frozen the pins and you still can't get them put together? I heated them to 150 but that didn't work so I kicked it up to 200 and that still didn't work. Any other ideas or tricks?

you could take a blow torch to heat up the end but not too hot i'm shure something around 400 degrees would work you just want to avoid messing up the grain structure in the metal making it more prone to fatigue.

This one is out of my league since I'm not a metallurgist, but I'd bet a machine shop would let you know a good temp. There are different ways to tell by the color of the metal. Like, "cherry red" indicates a certain temp range and "white-orange" is where it turns into a puddle of goo.

I know when I get my rods back (I usually let the machine shop do that) the small ends are all discolored from the application of heat.

I'll try a blow torch. I can't stand to let anyone else do something on my cars that there might be even a small chance that I could do it my self. So I really don't want to have to do that here.

wait on the blow torch. I would use a pot of heated motor oil to heat the rods up. I do it alot a work with press fit roller bearings, and they slide right on. Do not get the oil over 450 or 500 degrees though or it will remove some qualities of the metal if you get them to hot. This is also nice because the oil provides some lube.

Cool, alright I'll try that first them thanks

My tip is to used liquid nitrogen to cool the "inner parts". Unlike heating cooling won't damage the parts, unless you drop them or something like that.

Turn your freezer thermostat down. Liquid nitrogen is just a little hard to find. And they usually won't sell you a thermos full.

Usually you can rent a thermos, and buy the liquid nitrogen.

Dry ice can also be used, but one can't reach as low temperatures with that.

http://www.linde-gas.com/International/Web/LG/COM/likelgcomn.nsf/DocByAlias/ind_shrinkfitting

Usually you can rent a thermos, and buy the liquid nitrogen.

Dry ice can also be used, but one can't reach as low temperatures with that.

http://www.linde-gas.com/International/Web/LG/COM/likelgcomn.nsf/DocByAlias/ind_shrinkfitting

Thanks for the link it sounds like shrinking the pins are more important than expanding the rods. Thats good cause I tried heating it up in oil today and I just couldn't get it hot enough so it didn't work either. I'll try dry ice on the pins and maybe throw the rods back into the oven at 200 or 300 tomorrow then and let everyone know how that turns out.

Well apearently I just suck. Here's what I tried today I got some dry ice and put the pins under is with some schnapps that was nasty as could be and I wan't gonna drink it anyway. then I put that in the freezer for insulation. I put the oven at 200 first and put the rods in that and left everything for a good 30 to 45 minutes then pulled one of each out and tried to assemble it to the piston. It worked a little better than before with just the freezer but it still wouldn't go in. So next I upped the oven to 300 and left it for about the same time until the house started to smell like hot oil then pulled one of each out again which the pin I had to bust out of the frozen liquer it was so cold and tried to put them together but unfortunately I got the same results so evedently I don't posses the equiptment or skills to do this my self. I guess I'll have to find some one who can mount them around here and let them do it. Not all was lost though in the end I still had a big block of dry ice to play with so I put a bunch of water on it and let the fog reign over the kitchen simblizing my disappointment in the failed expeirements. Thanks to everyone for your input. Sorry I couldn't post better results for everyone to learn from.

Okay, new thought just acurred to me. The pistons I got came with pins obviousely but it didn't say what diameter the pins were. So my thinking is, would it be possible that the pins that came with them were to large for the rods? and if so what size difference should there be between the two? If the pins were say 1" diameter what diameter would the rod end need to be? I would assume a few 1000ths smaller but don't know for sure.