I've searched and couldn't find anything useful. Does anybody have any insight on how to install these in a set of Wiseco pistons? Do you need them? The literature that came with the pistons is pretty vague. I've got the wrist pins pressed in, but now I have to center them in the rod. Can I use the Spiroloc as a stop when I center the wrist pin?

Maybe I'm calling these things Spirolox and they're not. Maybe they're just snap rings. Here are some pics to help:



Here you can see the groove the snap ring, Spirolox or whatever they are fit into:


And this shows how the wrist pin presses into the small end of the rod, but floats within the bore of the piston.


My issue is how to center the wrist pin in the rod. Any suggestions? Has anyone done this before?

How 'bout... NO.

We all have different goals and the stock rods will be fine for mine. What can they handle? >500 whp? I won't be close to that. Using the stock rods is not a "wrong" choice.

Now can we stick to the original point please?

Quote:

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We all have different goals and the stock rods will be fine for mine. What can they handle? >500 whp? I won't be close to that. Using the stock rods is not a "wrong" choice.

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The 2g pistons would have been more than enough in your case then, as the 1g rod is still the weak link in a 1g/2g combo.

Brianawd: You're right. If I were building a 2.0, I would have used 2g pistons. But as you can see in the 2nd photo, these are stroker pistons.

prove_it: I'm not sure if that was directed at me, but I have Wiseco pistons and they came with wrist pins. They fit into the stock rods properly and I have already pressed them in. I just need to take the time to center each one now. This setup will be just like the stock setup with the wrist pin pressing into the rod and floating within the piston.

This is a low budget build, but don't think it isn't being done properly. For example, I had a friend of mine measure the pistons on a Zeiss CMM for roundness and diameter. He took 500 data points on the skirts. Then I took the largest diameter and added the piston-to-wall clearance and told the machinist what size to machine the block bores (3.36633"). Next week I'll have a bore gage set up to confirm the bores are the correct diameter. I did not come up with my plan for the engine build hastily. My choices are perfectly adequate for my goals.

It is true that the crank will position the rod where it needs to be. But the issue is not the location of the rod in relationship to the piston; that will take care of itself. The issue is the wrist pin in relationship to the rod. If you look at the 3rd photo above it may help. I want the same length of the wrist pin sticking out from each side of the rod. It will be a trial and error process because you can't see anything when it's set up in the press.

Have you considered making a jig with a hard stop for the press?

Most machine shops have a little oven that we use to heat the little end of the rod.

The piston is put in a fixture with an adjustable stop for the pin. The rod is heated, laid into postition against the bottom of the pin opening of the piston. The pin is dipped in oil and then the it goes in with a light push untill it bottoms against the stop..

Doing it this way ensures the pin is centered and the piston won't be subjected to the force of pressing the pin into the rod.

The press fit is pretty tight, and substantial force can be required to install the pin.

Doing it cold can result in distorting or even cracking the piston.

In addition, the pin can get scratched/gouged as it passes thru the rod bore. Those scratches/gouges will chew up the pin bore in the piston once the engine is fired up, resulting in all sorts of problems.

We also have another fixture the pistons are laid in to press the pins out at the beginning of the machining operations. It cradles the piston, spreading the load out to minumise flattening the backside of the piston pin bore, which will increase the amount of force required to drive the pin out.

That's why it's best to let the machine shop to install/remove the pins when using press fit style pistons.

I realise that doesn't help you now, but, Muskrat has a pretty solid idea.

Quoting Muskrat:

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Have you considered making a jig with a hard stop for the press?

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That's good thinking right there.

Combined with a curved fixture to lay the piston in, you should be able to reposition things slightly without any major carnage.

Quoting Muskrat:

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Have you considered making a jig with a hard stop for the press?

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The dimensions for this are in the 4g63 rebuild manual.

Do not use the clips with a press fit rod. If you actually pressed the pins into the rods, instead of heating the small end of the rod, you probably damaged the pistons.

Thanks to all of you for the good input/info.