Wrist Pin
 

Hey guys, I was just checking out all the 331 stuff I have laying around that I dont have the money to finish, and I got to playing around with the pistons and rods. The pistons are SRP and the rods are hawks racing I believe, they are forged. They both advertised using a .927 pin size, but the pin will not slide into the rod. It looks like it should fit, but is barely too big. Do they need to be pressed onto the rods or what. This may be a really dumb question, but hopefully someone can clear it up for me. Thanks, John

Yes they are a press fit.

Thanks Shaggy

Press Fit is actually a misnomer. What we do is put the rod in a furnace and heat up the small end. When they are properly heated, the pin literally slides into place. Then we remove the heat source, and as the rod end cools, it grabs the pin.

Most shops charge about 6.00 per rod to fit the pin.

I prefer pressed pins on street engines. The floating pins require bronze bushings, oiling capacity, and spiro-locks. I have seen spiro-locks fail, and the lunched engines are pretty much a big heavy paper weight.

We use floating pins on race engines where we dissassemble and test a variety of pistons, piston coatings, and the like.

Hope this helps.

Helps alot man, thanks. I wasnt sure about it because my buddy has built a few 5.0s and I'm assuming he used floating pins. SDo you recommend I do the furnace trick, or should I let a shop do it. Thanks again - John

Let a shop do it. They have a special jig fixture to hold everything in place and align the pin and the piston properly.

If you just try to do it at home, you will end up anealing the metal (making it soft) and that is NEVER A GOOD THING.

Any shop that builds engines can do this, and they will charge you less than 50 bucks. Money well spent. Do not use floating pins on a street motor. It costs MORE, it must be set up properly and that means providing OIL to the pin.

Gotcha man, thanks for the info. - John

Hey John,

How do you like that Zex 125 shot NOS?

They seem to be right on the cool edge of NOS delivery! Do you like the system?

u a ricer son???NOS is a manufacture...NITROUS is what the ZEX kit injects..ive installed the kit b4 and it works real well

I love the kit man, easy install, good power. No solenoids to mount, everything is in a small box they call a nitrous management unit. You thinkin about getting one? - John