[TR] Subject: Engineer Question again!

Tony Drews tony at tonydrews.com
Mon Apr 21 21:40:06 MDT 2014

Just went through an exercise replacing wrist pins in my custom 
Wiesco pistons.  Learned a couple of things in the process - pistons 
are made for either circlips or for spiral locks, and the wrist pin 
is made differently depending on which of those you run too.  The end 
of the wrist pin is flat for spiral locks and has a chamfer on the OD 
if running a circlip (to help push the circlip back into the groove 
in the piston, presumably).

I would imagine that a mismatched set of circlip / spiral lock in a 
piston / wrist pin made for the opposite one could result in the 
keeper leaving the piston.

The delrin button seems pretty foolproof, but I've never used them.

Tony Drews

At 08:30 PM 4/21/2014, Randall wrote:
>---- Catpusher at aol.com wrote:
> >  Perhaps you want to check  the snap rings in the other pistons
> > whilst you are in there
>Come to think of it, wasn't there someone advocating the use of 
>Delrin buttons rather than snap rings, for just that reason?  Along 
>the same lines,has anyone tried using spiral locks?
>Also, just a rumor, but I've heard it said that circlips that come 
>loose sometimes indicate the rod is not true.  Might be worth 
>checking as long as you have it apart.

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