Whats up with these wrist pins?

I bought new 42220 Manley wrist pins last year because i was advised to due to stroke and power increase. They have 14 dyno pulls and seven runs on them. My machinist called and said they were worn enough he didn't want me to reuse them! They supposedly should have been good enough, being .180 wall x 2.93 chrome moly. My CP pins were .150 wall and had over 300 runs on them and still looked good .
I called Trend and they had ONE SET of .205 wall DLC coated pins on the shelf. I bought them. They better hold up. $605 to my door.
I never did get the vacuum up so the motor never saw more than 4 inchs of vac. So my question is why would those Manley pins wear so quickly?

What’s your definition of wear?

Are you sure it is the pins wearing? I would think the piston pin holes would wear first since it is the softer metal?
Bent pin OK, but worn? Wonder if they were manufactured on the small side..

Just my opinion..

Dave

That wear is surprising to me too.

In the old days, using 0.150 wall pins was more common, but I changed my mind on that around 2014. And that was with 4.375" bore (lighter pistons).
I plan to use 0.185" wall pins, and have thought about tool steel (H13). Pistons around 575 grams.
Your 0.205" should be very strong.

My machinist said there was wear he could feel, and i thought he said there was some fretting? I haven't seen them and never looked that close when i removed them from my other rods and pistons. I went ahead and ordered the better ones. I will post a picture when i get them back.

I would send them to Manley and ask them what happened. Very unusual.

Prolly assembled dry

I'm assuming the rods are bushed which would make the wearing surface on both the rod and piston softer than the pin. Even if a dry assembly were responsible, one would think the pistons and rods would be damaged more than the pin.