1G Failed break-in, bearing wear opinions

[97gsxIA]

Long story short, I had a 6bolt shortblock built by one of the bigger names in the DSM community. Who I will leave off this post for now.

First oil change was clean, second was glitter. Crank had walked. End play was .011. Caught it early.

40 miles total. Pulled the engine, contacted the builder and he immediately started questioning my clutch setup. I walked through with him my setup, clutch adjustment measurements (confirming clutch wasn't preloading the crank) Yada Yada Yada. I even bore scoped a video of the mated engine/trans to prove the input shaft sleeve wasn't riding the clutch disk hub, as he also jumped to that conclusion.

I was expecting to see just the thrust surface worn up, but it was the thrust surface AND that entire half of the center main bearing.

Crank journals are spotless.

Curious of others opinions. I'm of the mind of a botched machinist or him not aligning the thrust bearing on assembly. Not to say my heavy pressure plate wasn't contributing... but to do it in 40 miles when I had the same clutch for 6 years on my last one is hard to believe.

Anyone have any thoughts on this wear pattern?

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[danl]

If you remove the bearing, is there debris under it? Is that bearing the proper size for your crank? It looks to be that it wiped the radial bearing surface due to insufficient clearance. The thrust surface was then starved of oil due to insufficient clearance and thus oil flow.

 

[97gsxIA]

No debris under the bearing.
Unfortunately he would not share the blueprint information with me. (I know a giant red flag and I made a huge deal out of it.) But his reputation and accomplishments is intense to say the least and I trusted him.... all the way up to when my crank walked 40 miles down the road.
I'm not gonna call him out until I give him a chance to fix the mistake (if it was in fact his). Gotta drive 5 hours to get it back to him.

Just looking for opinions from people who have more experience in diagnosing wear patterns, while I seethe with rage.

 

[CrackedDSM]

Not gonna lie, just from how you're describing his antics I think I can guess who it is already. Either way, keep us updated. Curious how this works out.

 

[97gsxIA]

Not gonna lie, just from how you're describing his antics I think I can guess who it is already. Either way, keep us updated. Curious how this works out.

Him and his car were the entire reason I stayed in the DSM game these last 15 years.

It's hurting my soul a bit, not to mention my wallet. And I guess that's all I really gotta say about it right now.

 

[CrackedDSM]

Him and his car were the entire reason I stayed in the DSM game these last 15 years.

It's hurting my soul a bit. And I guess that's all I really gotta say about it right now.

Never meet your heroes, and don't ever put your faith in a man. Sucks that he's being an ass, but one way or another we'll get it right and running. Keep ya' head up. No matter what he does.

I agree with at least giving the chance to make it right though. Give him enough rope to help himself, or hang himself. Shit happens and even something assembled perfectly can have freak accidents. I've said for years its not the mistake that I judge, its how they try to make it better/fix it/respond to it.

 

[DSMPT]

I was expecting to see just the thrust surface worn up, but it was the thrust surface AND that entire half of the center main bearing.

Anyone have any thoughts on this wear pattern?

This wear pattern is kinda typical for crank walk.

But to be honest, it's hard to pinpoint the cause by seeing only these pics. Besides bad machining or assembly error, improper clutch adjustment, too long crank with clutch switch, wasn't primed sufficient etc could be the cause.

 

[97gsxIA]

This wear pattern is kinda typical for crank walk.

But to be honest, it's hard to pinpoint the cause by seeing only these pics. Besides bad machining or assembly error, improper clutch adjustment, too long crank with clutch switch, wasn't primed sufficient etc could be the cause.

You're right, it's a real zoo cage of causality.
I can only rule out the few I have control of, and then ask him to verify his machine/assembly work. -And help get it back together.
This type of failure really puts the fear in you when it comes to 2nd attempts. So thanks for sharing your thoughts i appreciate it.

 

[1990TSIAWDTALON]

Looks like it was a bit too tight. That scuffing doesn't show up unless there is no oil or the bearing is too snug or walks. I would measure the thrust surface on the crank for a ballpark figure now.

 

[97gsxIA]

Looks like it was a bit too tight. That scuffing doesn't show up unless there is no oil or the bearing is too snug or walks. I would measure the thrust surface on the crank for a ballpark figure now.

Tight as in not enough clearance on the main? When you say measure the thrust surface you mean it's depth?

 

[danl]

Tight as in not enough clearance on the main? When you say measure the thrust surface you mean it's depth?

Can you share a picture of the corresponding bearing in the block. Also mic the crank outer diameter. Then get a measurement of the thrust bearing ID. Or if the bearings have the size stamped on them that would be useful as well.

I inherited an engine with undersized thrust bearing with an uncut crank. It junked the bearing and crank in 100 miles.

 

[1990TSIAWDTALON]

Tight as in not enough clearance on the main? When you say measure the thrust surface you mean it's depth?

Crank thrust surface THICKNESS in .000"'s
Did the crank have excessive pressure on it for an extended time for any reason?
Brand and type (part #'s) of the bearing? It should be on the back side. Also it looks like that bearing was just to tight on the journal to me, helping to contribute debris onto the thrust surface of the bearing, but that's all just a guess.
A built engine spec sheet should be available.

 

[97gsxIA]

I don't have mics and don't want to fumble around a dial caliper or pull the crank until the builder has an opportunity to examine it.

However I am restless so I wanted to know a ballpark bearing clearance. In comes the plastigauge.

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[1990TSIAWDTALON]

It's tight but it shouldn't have given you an issue if it was just being broke in. That .001" is TIGHT. I would have put a .001" OVERSIZE bearing on that journal.
Norm for my engines - .002" mains, .002-.003" rods on a normally used motor. Just what I do.

 

[danl]

The thrust gets its oil flow from the journal. You have half the clearance you should. You have half the flow to the thrust surface which provides the hydrodynamic wedge separating the crank and bearing with the clutch depressed. Perhaps with a stock pressure plate it would have lived awhile longer. You are running a heavier pressure plate with a thrust surface that has reduced flow. The old engine did not experience a failure with the same pressure plate. The problem likely lies with what is out of spec.

Seems to me you have demonstrated the bearing clearance was incorrect. The person you paid to build it should fix their mistake.

To reiterate, I bought a car that had a std crank with a .010 undersized thrust bearing installed. It experienced the exact same failure but lived “100miles” by what I was told. Your situation lines up with exactly what I’ve seen. That car was on a stock pressure plate.

 

[99dsmer4g63]

FWIW I wouldn’t tell the machinist that you checked the clearance and I would scrape the plasti gauge off so he doesn’t know.

The less he thinks you know the better. Let him talk himself into a hole first. There is a reason he’s not giving you a blueprint. Might not even have one for you because it wasn’t done.

Just my .02. Good luck and keep us updated.

-Daniel

 

[CrackedDSM]

FWIW I wouldn’t tell the machinist that you checked the clearance and I would scrape the plasti gauge off so he doesn’t know.

The less he thinks you know the better. Let him talk himself into a hole first. There is a reason he’s not giving you a blueprint. Might not even have one for you because it wasn’t done.

Just my .02. Good luck and keep us updated.

-Daniel

150% agree. I do this shit all the time. It’s what I mean by giving them rope enough to either help themselves or hang themselves.

 

[curt-s]

By rope to hang themselves with, what is the expectation? They can piss and moan about it but unless you're willing to bring small claims suit against them, they have all the power in the situation. I myself am just getting into facing the same thing except my anal retentiveness in having another shop double check the work of the first led to the discovery before anything was assembled. But if they ultimately tell me (and you) to pound sand, our retorts are either suit or public shaming. That's all.

 

[CrackedDSM]

By rope to hang themselves with, what is the expectation? They can piss and moan about it but unless you're willing to bring small claims suit against them, they have all the power in the situation. I myself am just getting into facing the same thing except my anal retentiveness in having another shop double check the work of the first led to the discovery before anything was assembled. But if they ultimately tell me (and you) to pound sand, our retorts are either suit or public shaming. That's all.

Public knowledge is powerful as is word of mouth. I wouldn’t discount it. Small claims court is relatively useless, as there is usually no defined payout timeline or minimum date to pay back rulings. Dale/BogusSVO bragged to me in person that he’d been ruled against in small claims court but never plans to pay anyone because there’s no “pay by this date” in SCC.

Bad word of mouth will kill businesses though.

 

[curt-s]

Small, perhaps.
Going up against a chain, no dice.
Don't ever get your shit done by a chain

 

[97gsxIA]

He's got a chance to hear me out and make an attempt to at least try and make it right. I will know more Monday.

I'm not expecting him to do that though. So if he tells me to pound sand I'll order a new set of bearings and do it myself.

There's nothing to be gained after that.

I lose a hero, possibly lose thousands and thousands of dollars, and he takes a hit in reputation (which he could probably care less about given his accolades)
Every conversation has been followed with "well my car has this and it holds the records"

Which feels just so great to hear while my car lies bleeding in my garage as a paperweight /s

 

[Brandon Mau]

bearing clearance is tight, judging by half the bearing ate like that and the other half not so much tells me the crank wasn’t preloaded correctly on assembly. ARP mains?

 

[curt-s]

This is the first I've ever heard of "preloading the crank". What does that even mean?

 

[97gsxIA]

He's talking about 'aligning' the thrust bearing. You pry against the crank while torqueing the center main to align the two halves of the thrust bearing on 6 bolts.

bearing clearance is tight, judging by half the bearing ate like that and the other half not so much tells me the crank wasn’t preloaded correctly on assembly. ARP mains?

Yes ARP Mains, with a kiggly girdle. And no- sorry I can't tell you if he actually align bored the mains for them. He told me he did. Which doesn't meant shit to me right now.

My next main concern is the thrust surface finish on the crank. Its not anywhere near mangled or damaged, but it also isn't perfectly smooth like a freshly machined surface.
Marty was alluding to measuring its thickness, but I can't really find any specs regarding the thrust surface of cranks to compare any measurement to.

 

[Brandon Mau]

Best video I can find but I do the same thing on my 4G.

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