Modifying Piston Pins

[CTX-SLPR]

Howdy,

I've gotten into the habit of scrounging through eBay and RacingJunk for the next part I need for my Bonneville motor. I just bought rods (oh yeah!) so now it's on to wrist pins. The pistons use 0.927x2.750in pins and I was looking to see if I can find some DLC coated units. I can't find any (currently) in the correct length but considering the price of a single new DLC pin (~$45+) there are some that are 0.200in too long for about twice that for a set of 8.

Now I have the old CirClip style pin retainers on my pistons, I have no idea if they take the same pin ends as Spiroloc's do but that could be another reason to get too long pins and have the ends turned down to the right length and shape.

Question 1: what style of pin end does a CirClip take?
Question 2: Can you shorten a DLC pin on common lathe tools?

Thanks,

[Dynoroom]

CirClips use a champhered type pin.

It is very difficult to cut wrist pins in a lathe, with or without DLC. Most pins are ~ 54-56C rockwell.
I have rigged up a air tool with a cutoff wheel but I don't recomend it.

[tardis454]

Most wrist pins are made out of case hardened mild steel, tough stuff to cut..
I'd cut the bulk of the material off with a chop saw.
Then remove the remaining material with a ceramic or carbide tool in the lathe.

[CTX-SLPR]

CirClips use a champhered type pin.

It is very difficult to cut wrist pins in a lathe, with or without DLC. Most pins are ~ 54-56C rockwell.
I have rigged up a air tool with a cutoff wheel but I don't recomend it.

Mike,

From my limited knowledge, this means that pins meant for Spiroloc's will work with the CirClips since they look to have that chamfered end.

I've thought about chucking one into my mill and trying to very very slowly cut the end down, sounds like I'd need to put an abrasive cut off wheel on grinder on the mill table and slowly feed the quill down and the grinder across sequentially. That sounds like a ton of work but my time is free in respects to the budget I'm on.

For Bonneville, is it a waste for DLC pins on even a 700hp at 7000rpm type engine? I'll be making ~117hp per hole at that power level but I'm starting at roughly half of that with parts (short of the block) that should hold up to the end state power level.

Thanks,

[Beagle]

http://aperaceparts.com/wristpins.html

check with these guys? Every pin I've ever jacked with, including Briggs and Stratton pins, are ungodly hard. The tools would chatter... I don't think it's worth the tool cost to bust them playing with pins. No intended offense, I just personally wouldn't consider it worth the effort and tool costs.

They are showing their shelf stuff at 90.00 / 4 , I wouldn't think they would charge a ton more for a set of six custom.