rod bearings gone, trying to understand why

[user-z68766209]

on the above #7 back side...
half on the left is that the upper? pic is dark but looks to be "working" in the housing

[user-z68766209]

Dan T: here is a pic of what I think is no 7 (?) piston after removal of the cap, looks like the radius is on the correct side


SLPRACING; I did not assemble the shortblock, it was done by an engine shop builder and I dont know how they measured clearences. They are somewhat involved in pro stock engines so I sincerely hope they are not relying 100% on plastigage...
Anyway, I will hand over the crank and the rods to another shop with great reputation that´s nearby to check out all rods and the crank.

not sure if this rod is up against the journal but the bearing tag on bearing to the tag groove in the rod
does not look right......

[MotionMachine]

Unless you had the crank checked out thoroughly, and I mean in a crank grinder with the arnold gage running of each journal, I would not trust an offshore crank out of the box. I've ground a lot of them from new, many of them I have been able to grind to the small spec of standard size because they were over the standard limit. Lots of shops with good machines have done this. They can have taper, out of round, radius creep into the bearing surface, even damage from excessive polishing.

[rally]

Why the high pressure oil pump? K&N oil filters are a good brand. Sometimes to much pressure can cause lack of oil lubrication on bearings. What does your factory motor of this type call for on the oil pump?

[KnightEngines]

The pic of the back of that rod bearing tells the story - detonation is what killed it.
All the other damage is just debris from the 1st pounded out rod bearing that has bypassed the filter.

The drop in oil pressure was most likely when the bearing let go - massive increase in oil clearance will do that!

To be safe you'll want to replace that rod (going by the bearing it's going to be beyond salvage), resize all the rods, including the new one, grind the crank to achieve .0025 rod & .003" main clearance.
Blank off the bypass in the pump & check the pickup height - should be 6-10mm from the bottom of the pan.

When she's up & running again keep a close eye on oil pressure for a while until you're sure there is no problem there.

[BrazilianZ28Camaro]

My wild guess is:

The OP said that pistons had no signs of detonation, so , maybe the spun bearing spun due too little crush on the main bore, the debris bypassed the oil filter and crapped all the other bearings.

But why not the #1 and #8 IDK.

Would be wise to check if the last cam bearing is all the way into its bore, otherwise the oil will scape through the cam journal . Also check if there is a oil plug under the last main cap. If not, the oil filter was useless.

[Kevin Johnson]

But why not the #1 and #8 IDK.

Rods 1 and 8 have legs in the SBC lubrication circuit that feed them alone.

[BrazilianZ28Camaro]

But why not the #1 and #8 IDK.

Rods 1 and 8 have legs in the SBC lubrication circuit that feed them alone.

Yes you're right, but the dirty oil would damage them too, right?

Another point that may explain what happened is:

Was that crank oil holes chamfered after or before polishing? Maybe some burr on the chamfer did the demage, or maybe the crank journals hadn't any chamfer at all?

[Kevin Johnson]

They only provide one rod bearing leak per leg so the hydrodynamic wedge at the rod bearing would have greater local pressure supplying it and be able to flush out debris better. They would simply be the last to fail not that they are anything special.

[Baprace]

The pic of the back of that rod bearing tells the story - detonation is what killed it.
All the other damage is just debris from the 1st pounded out rod bearing that has bypassed the filter.

The drop in oil pressure was most likely when the bearing let go - massive increase in oil clearance will do that!

To be safe you'll want to replace that rod (going by the bearing it's going to be beyond salvage), resize all the rods, including the new one, grind the crank to achieve .0025 rod & .003" main clearance.
Blank off the bypass in the pump & check the pickup height - should be 6-10mm from the bottom of the pan.

When she's up & running again keep a close eye on oil pressure for a while until you're sure there is no problem there.

I don't think that is detonation you are seeing on the back side, I would think that marking came after the engine lost some oil pressure and started knocking. JMO

I agree with your recomendation on clearances and rebuilding rods with a regrind on the crank.

[Warp Speed]

They only provide one rod bearing leak per leg so the hydrodynamic wedge at the rod bearing would have greater local pressure supplying it and be able to flush out debris better. They would simply be the last to fail not that they are anything special.

The debris would have trashed them too, no matter the flow rate.
Unless there are mystery filters in #1, #5 saddle feeds feeds?
What is weird, is that even the spun bearing doesn't show a bunch of heat................just everything in the center is trashed, but not really burnt up?!?
From the pictures it looks like a classic case of a bunch of debris going through.....................but 2-3-4 mains only???
The gouges in the lower mains show a huge debris trail, probably from the same debris that appears to be imbedded to either side of the oil groove. Why not 1 and 5?
Typically, detonation will show up as edge loading first on both rods and mains, especially with an H-beam rod design, and there appears to be none on the so................
As far as loosing #3 rod bearing, and the debris from it damaging everything else, again........why not 1 and 5 main and their respective rod bearings?

[Kevin Johnson]

, again........why not 1 and 5 main and their respective rod bearings?

Number 5 has a spinning surface (cam bearing) that centrifuges denser objects like metal debris into the adjacent lifter gallery. Number one is at the end of a prior series of three vertical holes that would tend to filter out heavier particles by gravitation.

[Warp Speed]

, again........why not 1 and 5 main and their respective rod bearings?

Number 5 has a spinning surface (cam bearing) that centrifuges denser objects like metal debris into the adjacent lifter gallery. Number one is at the end of a prior series of three vertical holes that would tend to filter out heavier particles by gravitation.

Really?

[Kevin Johnson]

, again........why not 1 and 5 main and their respective rod bearings?

Number 5 has a spinning surface (cam bearing) that centrifuges denser objects like metal debris into the adjacent lifter gallery. Number one is at the end of a prior series of three vertical holes that would tend to filter out heavier particles by gravitation.

Really?

Hey, you are the one asking.

[Warp Speed]

Alrighty then!!!