I need some advice. Im installing floating wrist pins with round wire retainer. the wrist pins have a flat edge on the end of the pin. A spiral retainer would be better. The wire retainers are .071 thick and this keeps the pin from fitting exact. Or you could say the retainer will not fit into the grove properly. I have beveled the top outside edge of the pin to accomidate the round wire retainer. this works perfectly. however on one of the pins I remvoed maby .005 to much and have that much side to side movement. It is .005 or less, would you be conserned about this?

Personally,I would rather see them all have .005 clearance. Who knows how much those pins will expand while running. I would rather they have some room to move,I have never seen any that have a tight fit up against the locks.

Keith

Pins for round wire retainers are supposed to have a 45deg chamfer on the od. You have pins for spirolocs or circlips. Contact the manufacturer and exchange the pins for the corract ones or the clips will come loose.

without the chamfer, the wire locks WILL NOT work without failing.

maybe i'm out of the loop here but who the heck is using wire locks these days? frankly i don't know why pin buttons aren't used more.

I have wire locks in my R5P7 Nascar engine. If they think that they will work better 500miles and 9000rpm, they will use wire locks.
I think they know what they are doing but it would be nice to know why they use them.

Like MB said... without the chamfer they will push
out... the chamfer pushes out from the ID

Dan i haven't looked into buttons on automotive pistons and obviously things have to be setup for them but if the only additional expense was $32 i'd add that for sure. i guess there could/would be a little weight penalty but i've never seen one fail or cause problems. we used them on the bike engines and they were so nice to work with. we had solid aluminum, solid teflon and aluminum bodies with teflon inserts. i know they used to use them a lot in aircraft. is there any real downside in automotive applications i'm not aware of? i guess if the wrist pin is in the oil ring their use might not be possible unless the button was reduced in diameter on the end but even that might not be a big issue. i do believe i've seen them used a little more recently.

Shoot, back 9in the day they used double Waldes TruArcs, two snap rings on each side, put with the sharp edges facing the edges of the groove. They'd sometines come out. Spirolocks were supposed to be much better.
Buttons were looked on as old-fashioned, maybe it's their turn again.

I have a feeling that the race engines using wire clips use them because they are easier to put in and take out without possibly damaging the piston, and because they work. My Mercedes M110 Hemi 6 uses them, they sure are easy to install.

R.

thanks everyone you convinced me. I ordered the chamfer pin today from J&E, will have them friday hopefully. I prefer the spiral locks but these pistons came with the wire which will work just fine with correct pin, thanks again. Rob