I have this set of new Speed Pro 440 forged pistons that has been sitting in the box on a shelf for several years. The pins are all stuck in the pistons. There is no rust on the pins. I sprayed the pins with wd-40 about a week ago and yesterday wrapped one with a plastic mallet a couple of times, but it did not budge. Any tips??
I going to sell them, but I want to make sure there is no problems first.

use something like pb blaster, or kroil. soak them overnight. other thing to do, is warm them up in an oven. try to push the pin out, while it's still hot. use a press, not a hammer.

So you don't risk damage to the pin or pistons check your local machine shop to see if they have a sunnen pin press. Do not try to do it with a regular hydraulic press you cannot square up the piston like you can with the right tooling of a sunnen press.

MLR426

Take a hair dryer or heat gun and warm up the pin boss area and push them out, you may have some corrosion If so scotch brite and WD 40 will help clean them up, make sure to use a rust preventive on them when you reassemble them, not WD40 WD40 = Water Displacement formula #40, it evaporates and does not prevent rust is what I think

+1 with Kroil or maybe a hair dryer or oven.

Heat!!!! Set them on top of the Kerosun for a minute they will come out--

Well I put one of them in the oven at 250 deg for about 15 minutes and was able to push the pin out with gloves on. No rust found. Just a tight fit.
Thanks everyone for the help.

run them under hot water the pins will loosen and slide out. keep it simple

Kriegers .. $1.50 lb ...

Now the wrist pin hole needs to be resized to
fit the pin properly, failure to do this will lead to unpleasant results.

Maybe.....What makes an engine produce power? Heat in the combustion chamber expanding gases pushing the piston down.

So it should be a given that nearly as soon as the engine starts running at all, the pistons warm up. By the nature of the two metals involved, the aluminum piston pin hole expands twice as fast as the steel pin.

I've seen this happen many times, take the piston out of the box and the pin appears to be stuck. At the same time I've never known an engine rebuilder doing a commercial type job to stop at this point and resize the pin bore. So it must not be a huge problem, at least for the average rebuilt engine.

IMHO it's a "nice to have" rather than a "must do".

R.

If I'm using new pistons and wrist pins with press fit rods I have the pistons and pins pin fitted to make sure that the wrist pin to piston clearances are at least .0008 to .0010, if there going in a rod that has wrist pin retainers where the wrist pin floats in tthe rod and piston I have the rods done also to the same specs. Race motors like a tiny bit looser, the piston alloy also plays into how much to use and room temperature can play into reading the clearances also, depending on which gauges your using

I think it's "vas ist das" what is that,

"vas ist los" is what is wrong, loosely

Joe

I said loosely...it is used that way too

Joe