Cause of crankshaft wear

[4eighteener]

I thought I was having a flat tappet cam issue, but upon teardown found the cam and lifters to be okay. Instead I found this eccentric wear pattern on the #1 rod bearing.
The top of the journal is at the same level as the #2 rod journal, but the underside is worn down .030 compared to #2.
Any ideas on why and what would cause it to wear in this pattern?
And is the crankshaft repairable?

 

[MOPAROFFICIAL]

Well let's see you have some grooves but even if you had debris in the motor it would carve itself a channel and not literally take the whole Journal down like that. Wonder if you have the right size bearings ?even then... so now comes down to who machined the crankshaft or rod, probably the crankshaft though. If it were detonation it would have probably beat the bearings out of it but not turned it down like that, and it would have been on the other side at TDC

 

[RustyRatRod]

Lack of lubrication.

 

[4eighteener]

There are definitely grooves from debris, but it doesn't seem like the typical 360° grooves. The crankshaft was a new out of the box scat crankshaft

 

[4eighteener]

Lack of lubrication.

There was a poster on this past summer that had a similar issue, and a lot of people speculated oil pump, but at least his wear was concentric all around the journal.
I am not saying it is not the cause, but it seems odd to wear in that way

 

[MOPAROFFICIAL]

There are definitely grooves from debris, but it doesn't seem like the typical 360° grooves. The crankshaft was a new out of the box scat crankshaft

You could check and see if that oil feed is clear, it would have burn up and Rod knocked right away

 

[4eighteener]

Well let's see you have some grooves but even if you had debris in the motor it would carve itself a channel and not literally take the whole Journal down like that. Wonder if you have the right size bearings ?even then... so now comes down to who machined the crankshaft or rod, probably the crankshaft though. If it were detonation it would have probably beat the bearings out of it but not turned it down like that, and it would have been on the other side at TDC

The bearing shells both std. The one marked upper was in the upper position, and the lower in the lower position.
The rod cap still had the tattoo marks from the bearing shell, so I can confirm that the tab was in the correct position and the bearing did not spin or get piggybacked

 

[4eighteener]

You could check and see if that oil feed is clear, it would have burn up and Rod knocked right away

I did check for a blockage in the crankshaft, but haven't inspected the feed passages in the block

 

[MOPAROFFICIAL]

The main bearing would have went if there was a problem oiling that journal. So I don't think you need to look there

 

[MOPAROFFICIAL]

I assume the motor turned by hand with typical resistance and wasn't needing a breaker bar stood on by an elephant..?

 

[4eighteener]

I assume the motor turned by hand with typical resistance and wasn't needing a breaker bar stood on by an elephant..?

Yes, it turned over easily. Without the pistons attached the crankshaft would spin freely on its own.
I plastigauged all the rods and mains when I installed them and they were all in specs

 

[dano]

Massive amount of detonation on that one cylinder?

 

[4eighteener]

Massive amount of detonation on that one cylinder?

I am not disagreeing, but wouldn't detonation be harder on the upper side of the journal and bearing shell and pretty much affect all cylinders somewhat equally?

 

[ch1ll]

Rods were reused from previous build? Did you have them reconditioned or checked for size and roundness? I'd contact scat with your problem. They have probably seen this problem before.

 

[4eighteener]

Rods were reused from previous build? Did you have them reconditioned or checked for size and roundness? I'd contact scat with your problem. They have probably seen this problem before.

No, they were new scat rods out of the box.
I did talk with the machine shop that did the boring, decking, and align honing of the block.
He recommended the same thing to contact scat. He doesn't do crankshaft repairs, and doesn't know if a cast crank can be welded, but suggested if a new crankshaft is required, to get a forged crank.
Unfortunately, I learned that lesson already and am now hiding mallory metal in my mattress in leu of cash

 

[jbc426]

Could it be from metal or grinding debris that broke loose from a less-than-clean block or crank that lead to almost like a grinding slurry in the oil? My uncle used to tell tales about practice of "green canning" bad people's engines. Claimed he heard of folks putting a grease-based, valve grinding compound in their engines back in the day. The results were brutal.

Not many people run Jomar 100% no-bypass oil filters, so I'm assuming you didn't either. It seems like it would have worn the bearing completely out before that much wear on journal. I'd suspect a soft journal.

 

[Desoto291hemi]

Was #1 rod turned the wrong direction ?

Tommy

 

[NC Engine Builder]

That's probably trash that was present during assembly. I did a 340 a year or so ago for a FABO member, his was also a "fresh rebuild" it was just like that. They had also left the 3/8 pipe plug out behind the oil filter, allowing unfiltered oil to circulate.

 

[4eighteener]

That's probably trash that was present during assembly. I did a 340 a year or so ago for a FABO member, his was also a "fresh rebuild" it was just like that. They had also left the 3/8 pipe plug out behind the oil filter, allowing unfiltered oil to circulate.

Yep, I did the usual suspects.I had the pipe plug behind the filter in, the hidden plug under the distributor installed, and the press in plug below the #5 cap

 

[4eighteener]

Was #1 rod turned the wrong direction ?

Tommy

Thanks Tommy, I got that right too!
Bevel facing the journal not the other rod

 

[4eighteener]

Could it be from metal or grinding debris that broke loose from a less-than-clean block or crank that lead to almost like a grinding slurry in the oil? My uncle used to tell tales about practice of "green canning" bad people's engines. Claimed he heard of folks putting a grease-based, valve grinding compound in their engines back in the day. The results were brutal.

Not many people run Jomar 100% no-bypass oil filters, so I'm assuming you didn't either. It seems like it would have worn the bearing completely out before that much wear on journal. I'd suspect a soft journal.

I do believe that slurry answer is as good as any. Although there are such deep groooves on the underside of the journal that don't continue around to the top, I don't know how that would work
Anyway, I suspect perhaps either a particle or slurry caused the initial damage opening up the gap, and the underside of the shaft probably started hammering the gap bigger and causing more damage etc,etc...
No I didn't use a jomar filter, but used a mopar filter for break-in and a bosch after the break-in.

 

[dogbreath]

Plenty of crank guys around who can repair that journal. Heres who I use , Steve´s custom crankshafts , Pinellas Park FL . I had a 340 steel crank with a badly pitted seal journal , he welded it up turned it down and polished the crank , looks like new , $125

 

[4eighteener]

Cool, in Florida too!
I reached out to Performance Crankshaft in Michigan, but it was too late in the day to get a reply

 

[MV8]

Have you checked to see if this rods assembled and torqued big end is concentric (checked at different clock positions)?

 

[4eighteener]

Have you checked to see if this rods assembled and torqued big end is concentric (checked at different clock positions)?

I did not.
I will do that in future builds for peace of mind