Rod bearing wear

[Raybo]

400 ci SBC. Callie’s rods and crank. Clevite bearings. Dirt mod turning 7800 RPM.

[Raybo]

Clearance from .0026-.0029” running 20w50

[modok]

bearing wear....
Ok, so, how much is it wore?

[Raybo]

Lines up with oil hole.

[bentvalves]

try giving it .003 - .0032" ? ?

how many laps or hours is that?

Im sure the engine was primed right before it was fired off yea?

[MadBill]

Three things I notice:
o One shiny track is at the outer edge of the shell as if the journal was a bit of 'hourglass' shaped or had too big a radius for the shell width.
o The witness marks run right out to the joint chamfer, which suggests rod ovality or inadequate bearing eccentricity.
o The marks appear to be only on the right side. I don't know what would do that on a rod bearing. (Or is the first pic a main, in which case perhaps a line bore issue?)

[Raybo]

try giving it .003 - .0032" ? ?

how many laps or hours is that?

Im sure the engine was primed right before it was fired off yea?

10 dyno pulls and about 40 laps. Was primed

[Raybo]

Three things I notice:
o One shiny track is at the outer edge of the shell as if the journal was a bit of 'hourglass' shaped or had too big a radius for the shell width.
o The witness marks run right out to the joint chamfer, which suggests rod ovality or inadequate bearing eccentricity.
o The marks appear to be only on the right side. I don't know what would do that on a rod bearing. (Or is the first pic a main, in which case perhaps a line bore issue?)

All pics are rod bearings

[Kevin Johnson]

Three things I notice:
o One shiny track is at the outer edge of the shell as if the journal was a bit of 'hourglass' shaped or had too big a radius for the shell width.
o The witness marks run right out to the joint chamfer, which suggests rod ovality or inadequate bearing eccentricity.
o The marks appear to be only on the right side. I don't know what would do that on a rod bearing. (Or is the first pic a main, in which case perhaps a line bore issue?)

The other rod on the journal appears to have the head of the tightened bolt offset towards the right or midline (it does not appear to be centered in the machined pocket). As the other rod (cap), holding the bearing in question, is for the opposite bank, does its tightened bolt replicate this offset towards the midline?

[tuffxf]

Gday,
What does the top shell look like?
Have you looked at all the other rod bearings?
What main bearing clearance and oil pressure? No oil control issues with the pan?
What rod bearings?
I see not enough eccentricity or the rods are pulling in at the parting lines?
What made you look, find a little in the filter?
Is this a new combo?
Cheers

[modok]

Still unclear on the point.
are you showing off how little they are worn?

[naukkis79]

Is there some kind of problem with those bearings? Seems fine to me.

But changing 20W-50 mineral oil to something modern can greatly improve bearing life in high-revving engines. There are blends also suitable for flat tappets engines. If someone insist to use mineral oils, single-grade oils are much better flowing so better for lubricating rod bearings in high rpm. Those multi-grade mineral oils are filled with viscosity-index expanders which limits oil flowing and make rod bearings temperatures to rise.

But those bearings seems fine to me, there's no reason to freak out from little bit shining from used bearings in high-revving engines.

[Kevin Johnson]

Three things I notice:
o One shiny track is at the outer edge of the shell as if the journal was a bit of 'hourglass' shaped or had too big a radius for the shell width.
o The witness marks run right out to the joint chamfer, which suggests rod ovality or inadequate bearing eccentricity.
o The marks appear to be only on the right side. I don't know what would do that on a rod bearing. (Or is the first pic a main, in which case perhaps a line bore issue?)

The other rod on the journal appears to have the head of the tightened bolt offset towards the right or midline (it does not appear to be centered in the machined pocket). As the other rod (cap), holding the bearing in question, is for the opposite bank, does its tightened bolt replicate this offset towards the midline?

offset.jpg

Perhaps checking the neighboring rod bearing will indicate if this is a significant issue or not.

[Raybo]

I had to reseal the pan and wanted to spot check the bearings while I had it down.

Compstar crank and rods. Clevite bearings. .0026”-.0029 clearance.

10 dyno pulls and about 40 laps on this engine. I’m going to run it and keep an eye on the filter material. We change oil every 2 nights.

[dannobee]

I see two issues that concern me. Not a criticism or anything, just something to keep an eye on.

The wear at the edge looks like a fillet radius problem. Does the crank require narrow bearings? Are you using the recommended bearings?

The wear in the middle looks like a riser left over from the oil hole drilling operation.

If the engine already has a few races on it, personally, I'd probably be likely to just leave it as is and keep an eye on it.