Damage wrist pin?

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
88bluestar
Pro
Pro
Posts: 378
Joined: Sun May 21, 2017 7:39 pm
Location:

Damage wrist pin?

Post by 88bluestar »

What would cause this? PBM Piston PBMPF4040550

Only pin with this issue.
You do not have the required permissions to view the files attached to this post.
mag2555
Guru
Guru
Posts: 4584
Joined: Sun Sep 18, 2011 11:31 am
Location: Heading for a bang up with Andromeda as we all are.

Re: Damage wrist pin?

Post by mag2555 »

Just plain bad metallurgy?
If that’s pitting then I would expect to see those small particles loaded into the wrist pin bore.

Is that the case?

That looks to be the area on the pin where the oil ring groove has a drain hole going to.

Was any polishing or rework done to the pistons and that one drain hole not cleaned out fully?
You can cut a man's tongue from his mouth, but that does not mean he’s a liar, it just shows that you fear the truth he might speak about you!
88bluestar
Pro
Pro
Posts: 378
Joined: Sun May 21, 2017 7:39 pm
Location:

Re: Damage wrist pin?

Post by 88bluestar »

Pin bore has some wear but nothing major. Going to replace pin.
BillK
Guru
Guru
Posts: 1745
Joined: Wed Aug 26, 2009 8:30 pm
Location: Beautiful Southern Maryland
Contact:

Re: Damage wrist pin?

Post by BillK »

Looks like corrosion. Most of PBM's pistons are Mahle and I have not seen anything like that.
Bill Koustenis
Advanced Automotive Machine
Waldorf Md

www.enginerepairshop.com
BillK
Guru
Guru
Posts: 1745
Joined: Wed Aug 26, 2009 8:30 pm
Location: Beautiful Southern Maryland
Contact:

Re: Damage wrist pin?

Post by BillK »

Looks like corrosion. Most of PBM's pistons are Mahle and I have not seen anything like that. Any chance it was like that from new ?
Bill Koustenis
Advanced Automotive Machine
Waldorf Md

www.enginerepairshop.com
User avatar
modok
Guru
Guru
Posts: 3321
Joined: Sun Jun 06, 2010 1:50 am
Location:

Re: Damage wrist pin?

Post by modok »

Agreed, looks like damage from exposure to dihydrogen monoxide
Chris_Hamilton
Pro
Pro
Posts: 316
Joined: Sun May 24, 2015 11:50 pm
Location:

Re: Damage wrist pin?

Post by Chris_Hamilton »

modok wrote: Fri May 26, 2023 11:40 pm Agreed, looks like damage from exposure to dihydrogen monoxide
:lol: :lol:
High quality metal, body and paint work
http://www.spiuserforum.com/index.php?t ... inia.9030/
88bluestar
Pro
Pro
Posts: 378
Joined: Sun May 21, 2017 7:39 pm
Location:

Re: Damage wrist pin?

Post by 88bluestar »

modok wrote: Fri May 26, 2023 11:40 pm Agreed, looks like damage from exposure to dihydrogen monoxide
Reminds me of this!

Oxygen, hydrogen, sulfur, sodium and phosphorous walk in to a bar……..


“OH SNaP” says the bartender!!!
Momus
Pro
Pro
Posts: 307
Joined: Tue Aug 13, 2013 8:38 am
Location:

Re: Damage wrist pin?

Post by Momus »

Looks like bark on undersized bar stock used that didn't grind clean.
allencr267
Pro
Pro
Posts: 362
Joined: Wed Nov 07, 2012 6:28 pm
Location: Tallahassee Florida USofA

Re: Damage wrist pin?

Post by allencr267 »

1 of 16?
Sweat during assembly without lube.
DNA?
Really surprised that pin's bore isn't nasty!
Tuner
Guru
Guru
Posts: 3184
Joined: Sun Apr 01, 2007 5:26 am
Location:

Re: Damage wrist pin?

Post by Tuner »

Eating salty potato chips during assembly?
amc fan
Expert
Expert
Posts: 598
Joined: Wed Jul 11, 2012 7:03 am
Location: BETHLEHEM PENNA.

Re: Damage wrist pin?

Post by amc fan »

Heat treatment scale that possibly did not clean up in the centerless grinding process.
Post Reply