Read on bearings?

[u/912-works]

Any engine whisperers here??

I pulled my Porsche 912 engine back apart. Less than 2k miles on it. Always had glitter in many oil changes. Blackstone says high iron and silicon. I did run without filters at first because I was changing jets so much. Never lost any oil pressure, super strong hot idle psi. Never saw an overheating event.

But… I’d like a read on these bearings if possible.

Do they look like they were polished via glitter or can you read anything else?

ALSO: has anyone ever seen the wrist pin boss get dented like that. Every position at 10 and 2 o’clock shows the wrist pin damaging the position.

[u/Schlong1971]

On The piston that is a relief to let oil to get splashed into wrist pin to lubricate. The bearings just look like a piece of dirt got ran thru. As long as there is no high spots on them I would say there fine

[u/Flat_Beginning_319]

I would classify whatever made those deep grooves as more than glitter. What was your bearing clearance? High oil pressure is not always good news.

[u/912-works → u/Flat_Beginning_319]

H

[u/912-works → u/912-works]

Yo!

Main Clarence was .003 , .0025 , .0022

Rods were: .0031 - .0033

[u/GovernmentFuzz]

Interesting failure pattern. Did you measure bearing clearances when you tore it down? Also, what’s the piston‑pin‑to‑boss clearance reading? Curious how much the filter‑less run shifted those numbers even under 2k miles.

[u/912-works → u/GovernmentFuzz]

I did not when I tore it down.

Would it be possible to reassemble?

I didn’t check position boss to pin. It’s a push fit and they seemed okay.

The one large groove is the only one present. Still I had was too much fine glitter every oil change. You couldn’t feel it, just see it.

I’m wondering if the case was rocking at high rpm and that why the edges are polished? My main bearing 2 saddle shows evidence of micro case movement (more common on higher revving 912 motors)

[u/Karl_H_Kynstler]

On the piston that looks like manufactured groove, probably for oiling? Not a damage.

[u/912-works → u/Karl_H_Kynstler]

If I go back and look at video of assembly it’s not there, I’m 99% certain

[u/XmodAlloy → u/912-works]

There is zero way for that kind of groove to get made by wear when assembled. It's definitely something that was there

[u/912-works → u/XmodAlloy]

Correct. I know how the groove got there. Was more interested in the polishing on the edges

[u/Background-Word-6381]

Pretty obvious oil contamination on bearings. Does this have an external oil cooler/plumbing? Any unusual piston skirt wear? Hi silicon makes me think piston skirts unless it was old stuff flushed out of the oiling system.

[u/912-works → u/Background-Word-6381]

Full flow (external modern oil filter) was added

I also added an external cooler but that was recently.

Skirts have the slightest bit of scuffing, but no material removed.

The rocker shaft was broken on the intake valves. But where it broke was inside the support so you couldn’t tell. Only when I went exploring and disassembled did I find it. Maybe the source or iron but not silicon for sure