Well I bought a new set of I beam rods attached to a new set of SRP pistons I want to use on my le2 build. They are PRESS FIT rods. I now have floating h-beam rods....can I still use the SRP pistons on the floating rods or do they need to be floating Pistons to work with the floating rods?! Thanks ---

 

Uhhh no but now you need a machine shop that has a pin heater to install them.... for the $20 more a set of rods you should have done the bushed rods.

Bret

 

I know, you talked me into the bushed floating h beams that I now have.

I originally purchased the NEW srp pistons and NEW i beams w/ pressed fittings pre-installed from someone on this forum . Good to know I just need a shop to unpress the i beam setup and I can still use the pistons, thanks ---

 

You'll probably want them to externally hone the pins for you as well.

Bret

 

Choose a good shop and be sure to tell them you are going to re-use the pistons. It's easy to damage them when removing the pins.

Rich

 

Let me ask several stupid questions relating to the post.
1. Can you get pistons in either press-fit or bushed?
2. Bushed rods must be used with bushed pistons?
3. Pressed rods must be used with pressed pistons?
4. Do bushed rods and pistons require pressing in any way shap or form or is it like snap rings or similar?
5. What are the advantages or disadvantages to bot pressed an bushed?

 

1. Can you get pistons in either press-fit or bushed?
The pistons are the same.

2. Bushed rods must be used with bushed pistons?
See above, it's the rods that differ.

3. Pressed rods must be used with pressed pistons?
See above.

4. Do bushed rods and pistons require pressing in any way shap or form or is it like snap rings or similar?
All pistons need some form of pin retention (SPIROLOX, WIRELOX, PIN BUTTONS).

5. What are the advantages or disadvantages to bot pressed an bushed?
Most stock wrist pins will be held in place by an interference fit. A press fit pin is harder to assemble and disassemble. If the rods have been shot peened or heat-treated, you should not heat the rods to assemble them. It is very hard to press a pin in or out of a rod without doing damage to the piston. For most street engines a press fit will work fine. In higher output engines, the heat in the piston can arc the piston more and require an extra 0.0005" pin clearance to prevent galling. Full floating pins eliminate the need for this. It is possible to use a full floating pin with a stock rod, but we run into the question, is it worth it? If it's a drag only car that sees very few miles, the rods can be honed out so the pin rides directly in the rod. With good oiling, this steel-to-steel fit can last a long time in a drag car, but shouldn't be done in a street engine. If you want to bush the small ends (you must have a good set of rods with enough meat around the small hole) you have to bore it .050" oversize to accommodate a .025" wall bushing. Some engine builders drill holes in the top and bottom of the pin bores for oil, but this can weaken the rod, it's better to just file a .010" slot on each side of the bore to let oil in (this works whether you use a bushing or not).

Rich

 

I know japanese 4 cycle motorcycle engines use rods with bushings on the ends and full floating pins although it may be for a different reason.

 

For further clarification....

You can use a piston designed for a floating rod with a pressed rod, but you cannot use a piston designed for a pressed rod with a floating rod.

The piston must have snap ring grooves for pin retention in order to use a floating rod. Most OE replacement pistons do not have this groove.

Your SRP's will work with either.