Premature thrust bearing wear (pictures inside)

[YZFR1]

Trying to figure out what could have caused this. All bearings look good except the thrust bearing. The oil clearance was .0015"-.0017" measured with a bore gauge and double check with plastigauge. The engine spun freely with one hand and without extensions. Thrust bearing journal on the crankshaft had about .0001" of run-out and end-play was about .003".

Any constructive feedback is appreciated

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[bryanwheat]

Looks like you got some debris in that journal.

 

[JusMX141]

That, or the block wasn't align-honed properly....meaning that particular journal was out of sync or "crooked" compared to the others, and the crank tore it up. Plastigage can't possibly tell you if your journals are in line or if there are any hidden "high spots" that appear around the entire 360* surface of the bearing.

Did the crank seem to spin freely when you first installed the crank during your build? Any binding or restriction would've been a dead giveaway of an alignment issue.


I'm seeing some nuts laying there that appear to be ARP's....did you install ARP main studs without getting the journals align-honed? That may be your problem.

 

[YZFR1]

The mains were check with a machinist straigh edge and were all found to be straight. The crankshaft turned like on butter right after the assembly and even when this happened. The block and crank were washed at least several times. Could pre-ignition could have caused this by any chance? That's the only thing i can thing of at this time, i was heat soaking my stock side mount and was getting some detonation which i'm afraid could have turned into a preignition. But compression and leak down numbers are good.

Also, wanted to mention that this didn't show up in the first oil filter but the 2nd one after 175 miles and 180 miles total on the motor.

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[BogusSVO]

Did you check the crank for bend?

Sorry Bryan... I would not say trash in the oil for this one.... The bearing looks blistered and flaked, not scraped and gouged.

IMHO.. .0015-.0017 seems a slight bit tight for a main.. General of thumb is .001 per inch of journal

With the std shaft dia being 2.2435-2.2441 I would like to see appox .002 -.0025 clearace
The spec I have for main oil clearance is .0008-.0032

With the extra heat generated on that bearing thrust face, with the tight oil clearance... I would have to think that the oil boiled/vaporized causing the bearing damage

In short.. not enough oil was flowing thu there to absorb the heat and transfer it away from the crank face and journal face.

Edit

Good that you checked with a straight edge.. you used the flat style, witch has 2 points of contat.. great for block and head surfaces... but when checking a round surface, like mains or cam bors a machinist round straight edge works better.

 

[bryanwheat]

Did you check the crank for bend?

Sorry Bryan... I would not say trash in the oil for this one.... The bearing looks blistered and flaked, not scraped and gouged.

IMHO.. .0015-.0017 seems a slight bit tight for a main.. General of thumb is .001 per inch of journal

With the std shaft dia being 2.2435-2.2441 I would like to see appox .002 -.0025 clearace
The spec I have for main oil clearance is .0008-.0032

With the extra heat generated on that bearing thrust face, with the tight oil clearance... I would have to think that the oil boiled/vaporized causing the bearing damage

In short.. not enough oil was flowing thu there to absorb the heat and transfer it away from the crank face and journal face.

My second guess was going to be lack of oil, your expertise it always good for these type of questions though.

 

[YZFR1]

Did you check the crank for bend?

IMHO.. .0015-.0017 seems a slight bit tight for a main.. General of thumb is .001 per inch of journal

With the std shaft dia being 2.2435-2.2441 I would like to see appox .002 -.0025 clearace
The spec I have for main oil clearance is .0008-.0032

With the extra heat generated on that bearing thrust face, with the tight oil clearance... I would have to think that the oil boiled/vaporized causing the bearing damage

In short.. not enough oil was flowing thu there to absorb the heat and transfer it away from the crank face and journal face.

"Check the crank for bend?" Do you mean the run-out and end-play? That's the only ones i know of but they were all with in spec. Is there another way to check the crank for bend?

I did think that the clearances were a tad on the tighter side but they were still with in spec and i didn't plan on revving this motor past 7k rpm.

BTW, the oil pressure was 16 psi fully warm and about 80 psi on start ups using a 15w40 Delvac 1300 Diesel oil

Do you think some race bearings could solve this one?

Thanks again for the feedback everyone

 

[BogusSVO]

When you spoke of run out, I thought you ment the thrust face on the crank.

But with the pic you posted, you measured what I was speaking of.

I doubt just installing "race" bearings will solve the issue.

Personally, I would have the mains polished again, giving the machine shop the spec you want on the shaft so you will end up with the oil clearance you need.

Why are you running the diesel oil? for added ZDDP ? That has been dropping in diesel oil for the past 5 or so past years...

If you want the cheap way out.. good dino oil and a 4oz bottle of "Melling Lube" Red gel...

 

[YZFR1]

From the research i did some people have recommended Mobile1 Delvac oil for engine break in because of high zinc content. Should i not use it?

I would look into dino oil and Melling Lube

 

[BogusSVO]

Yes, using diesel oil back in the day was the way to break in an engine. Due to it having the higher zinc/ZDDP content.

But that is no longer true, fed regs has been mandating a drop in ZDDP to meet emission standards, even in diesel oils.

That is why most all new engines have roller cams, and low tention rings.

When I send out a domstic engine with a flat tappet cam, I tell them to add a bottle of melling lube at every oil change to add the ZDDP that the cam needs for load bearing and padding, so they will not round the lobe of the cam off.

 

[1g-awd-talon]

This is above my knowledge as a nube but had the same trouble out of a h22 replace ten and everything was fine