What would cause this weird bearing wear?

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RustyRatRod said:
What were the crank bearing clearances upon the first assembly?
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I was looking for the paper where I wrote everything down and didnt see that on there, so I cant remember what it was off the top of my head unfortunately, but something mustn't have been quite right.


moper said:
Bearings are protected from physical damage only by oil pressure. Pressure is cause by resistance to flow - in bearings' case that comes from proper clearances and properly shaped (parallel) surfaces on the bearings and crank's journals. Especially on the mains, where the oil is pumped in, and then has to go through the crank to the rod bearings, journal finish and clearance is critical. I like a main clearance a little tighter, beacuse there's less leakage before the rod bearings get it. If the jourrnal(s) are tapered, the oil can escape and will not have a consistent load carrying capacity. This can be very localized on the bearing. Too loose is worse IMO in a main clearance than too tight. That's what I see on yours. The journal surface isn't truly flat, and the oil clearance may be a little too wide at some points around it. Remember the bearing bore is not perfectly round - it's tghtest at the top and botton perpendicular to the cap parting line. If the crank is not flat and the journal a little small because it was only polished you're asking for problems in the long term. Contaminants will scrape along the bearing making scoring down into the copper, or embed in the surface where you can see them. The marks are a bit different than yours. Oil starvation even at startup would affect all of them, and #s 1 and 5 are fine. So it's something else in my opinion. If you didn't measure (you used plastigage) you simply don't know if the journal was good. You know the clearance was in spec. If as you say the shop said it was marginal but usable - I'd say that's some confirmation. The Arnold gage they use is much more precise than a micrometer. A mic will see the taper if the temperature is right, enough measurements are taken, and the person measuring can read it correctly.
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That makes alot of sense, thanks for the very detailed answer. I will take the crank in to be measured to make sure everything is good, but I expect it to be good since it was turned and I am fairly sure that they measured everything after the turning.
 
never assume anything the last couple of rebuilt cranks I got were way off ,one bent with .008 run out on the center main (they ground a bent steel crank) ,the other ground too much on the mains . they came up with .033 main bearing set. to get .0025 .(someone grinding crank didn't have his glasses on that day)clearance on the main bearing. always check bearing clearance and straightness .
also end play.
 
plastigauge is not the most perfect accurate way, but it will work.

most of us old timers use white lithium grease on the rod/main bearing/crank surfaces at final assembly. it will last until the engine gets up to temp, then it washes away in the oil. the motor oil takes over at that point. motor oil dont lubricate well until it's up to temp.

i put it on dizzy gear & timing chain also. cam bearings too. cam lobes get the other stuff. lifters you can soak in motor oil and if hydraulic you can pump them with an old push rod to make sure some oil gets inside of them

you could also put a little white lube on the rocker shafts where the rockers sit, etc. just dont glob it on. globs can block passages temporarily. use thin coats. remember when you torque things, it will force some of it out.

also you can put a lil bit inside the oil pump on the lobes. it helps it get good suction at startup.

new oil pump. dont leave home without it. $40 insurance lol.
 
Lube the bearings with motor oil... Set the crank in.. Tighten the caps to spec and see if the crank is tight to turn... If it's smooth. That parts should be good... Pull it back apart and see if the bearing are scuffed... If not Clean the bearings and pt it back together with Luberiplate...
http://www.lubriplate.com/Products/.../Lubriplate-No-105-Motor-Assembly-Grease.aspx
If it's tight, you need to fin the problems as discussed above... :)
 
Stupid question but did you have all the main caps in the right places and the right way around?
 
So I just got back from my machine shop now. The crank was polished before being used, and that he wouldn't be surprised if the journal was a bit tapered. But he said that once he turned it he measured everything to make sure everything was true like it should be.

But because ive known these guys for a while they are going to help me out. He told me to bring in my block, rods/pistons and crank and leave them there for a few hours (to get up to temp). He will let me torque everything up and he will then measure everything to determine the bearing clearances. He said that he doesn't like using platigauge as it can sometimes not be as accurate. So he will be measuring it all how he does it. And he said he wants to help me out so he wont charge me! Ill have to bring them a case of beer or something lol

And to answer the other questions, the main caps were the right way (tang to tang) and the oil holes were lined up, the caps were also no mixed up.
 
Great news. Ask what he drinks and give him some. That's how that all works...lol.
 
I will! Pretty happy that they offered to to do that!

And I spent all day cleaning up all of my parts and noticed a few things, and I hope that they are not significant issues.

The pictures are of the big end of the rod, the thrust bearing cap and the 2nd main.

The rod has ARP rod bolts so they are super hard to take apart, it was probably me when I first put this motor together, but there are little marks like they were pried apart with something, nothing feels raised though, should that be smoothed down?

The thrust bearing damage looks older, but regardless its still there, it looks like its been nicked, but on the side, a bit larger but it doesn't go under the bearing so I dont know what to do about it.

On the 2nd main there are two little nicks on either side, cap too but really small. I know I did this one, when I was cleaning all of the bolts yesterday I loostened up the cap and bunped it and it fell a bit and did that (I caught it before it went down the bores. They are only on the outside of the surface, where it tapers, and I dont think the bearing even goes there.

Is all this damage superficial? And if not how should I fix it?
 

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with a knife sharping stone with a little oil as lube for the stone. use a new stone so it will be flat.
 
You NEVER pry on the rod cap. When I cycle rods (in a fixture - not in an engine) I use the handle of my soft dead blow to loosen the cap. It's hard to dssecribe but it doesn't take any real effort and the force is applied (tapping lightly) on the sides of the saddle. It can be done with the bearing in place - you don't hit the bearing - just the cap. In any event - if there are marks there that can catch a finger nail they need to be take out. Any mismatch in the surface can cause the cap to go on cocked affecting clearance and lessens the ability of the rod to do it's job.
 
DartVadar said:
.............

Is all this damage superficial? And if not how should I fix it?
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IMO, stone them with a 600 just to remove anything that is "raised" above the normal surface. Don't go crazy on them and try to remove the divots entirely.
 
Yeah that was probably my mistake. I didn't do that this time round taking them apart, it happened last year (well 2013) when it was first built, so the motor was actually already ran with those marks, and the rod bearings all looked pretty good (was just the main bearings really that were the problem). This time I got them apart without any prying, I just hit them with a soft hammer and they popped off.

It's only like that on a few of them, there isn't really anything I can catch my finger on, but I will inspect every rod for raised marks. Pretty annoyed at myself for not being smarter when I did this.
 
Anyone who says they've never done something wrong out of ignorance or (worse yet) excitement is lying...lol.
 
moper said:
Anyone who says they've never done something wrong out of ignorance or (worse yet) excitement is lying...lol.
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Im admitting that I did it, and It was probably a bit of both that caused it lol. Well I will make sure there are no raises edges. I guess I learn't to NEVER do that again.

Took my block, crank and rods/pistons in and will get all the clearances measured soon, hopefully everything is good!
 
Just kinda an update.

The clearances were measured at the machine shop, everything was cleaned meticulously as well. I began assembly of the short block, and used some proper assembly lube on the bearings. I installed the crank and put the caps on and set the thrust bearing. (Measured crank end play too and it is within spec). Made sure the crank turned easily after torquing each main. Once they were all torqued the crank spun really nice (thick bearing lube made it more difficult, but spun easily with one hand). I then installed the rods/Pistons and torqued everything down, engine still spins nice, turns nice with a smaller wrench, then checked rod side clearance.

As far as I know I've checked everything, and so far it's all where is should be.

But today I was looking at the bottom end and looked at the main caps. Some don't sit flush with the block, like one side I can catch my finger nail while I can't on the other, some seem almost "crooked" one side has a larger lip than the other. Caps are the right way, and in right order, also same bolts as before. I looked at the thrust bearing and it looks like it's perfectly flush on both sides. The caps fit super snug in the block registers so there is no wiggle room to make the cap crooked. Would this just be the factory tolerances in the caps? The block was line honed when I first rebuilt it and the mains were good (was even written on the block that they were). Just wondering if I somehow got them out of alignment when I put them on, when we were checking bearing clearances everything looked good with the bearings, I didn't notice the caps then, but also wasn't really looking.

Would this just be the factory tolerances in the cap to make them only fit one way? Or should I loosen the caps and try and line them up? When I installed them I just placed them on the journal, started the bolts by hand, and tapped the cap into place lightly with a rubber hammer, then torqued them, because I thought they line up automatically, could be wrong though.
 
I'm sure more experience will come. I'll ad this though.
I wouldn't be surprised on the mismatch from factory. But then, unless you've had the engine since manufactured, you likely don't know if the caps are original to the block I'd think.
It doesn't sound as though you are seeing or feeling rotation resistance due to the condition.
When you say "like one side I can catch my finger nail while I can't on the other" do you mean front to back or cylinder bank to cylinder bank?
Do the caps or block have corner breaks that can enhance the issue?
Did your main bolts turn in straight or wobble as you ran them down?
You could try to reset the caps. It may just end up the same, split the difference, or even move the offset to the opposite side.
The thrust bearing will control the cranks fore and aft motion.
 
Daves69 said:
I'm sure more experience will come. I'll ad this though.
I wouldn't be surprised on the mismatch from factory. But then, unless you've had the engine since manufactured, you likely don't know if the caps are original to the block I'd think.
It doesn't sound as though you are seeing or feeling rotation resistance due to the condition.
When you say "like one side I can catch my finger nail while I can't on the other" do you mean front to back or cylinder bank to cylinder bank?
Do the caps or block have corner breaks that can enhance the issue?
Did your main bolts turn in straight or wobble as you ran them down?
You could try to reset the caps. It may just end up the same, split the difference, or even move the offset to the opposite side.
The thrust bearing will control the cranks fore and aft motion.
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I think the mains are original, but even if they aren't they were line hones so they will work, and everything was measured so I'm sure they will work.
What I mean is that from cylinder bank to cylinder bank is slightly different on one main only, the rest are pretty close that way. The others slightly hang over going front to back, It was probably like this last time I put the motor together as well without ill effects, but my other bearing issues earlier in this thread were caused by the crank journal not being as round as it could be.

The bolts went in straight as well and, just dont want to have something slightly out of whack causing the bearing to be off, but then again that could just be the way the cap was originally when it was line honed? I will put up some pictures as it just makes things easier.
 
Just some pictures, I start at #1 and take a picture of both sides of the main (bank to bank).

#1 seems to overhang to the front of the engine, but even bank to bank, but flush on inside.

#2 Only one that I think has slightly more ridge to catch nail on when compared to other side (bank to bank and not front to back of engine).

#3 The cap seems pretty straight bank to bank, and thrust looks perfectly lined up.

#4 More ridge front to back but even bank to bank.

#5 Nearly flush with back of the block and even bank to bank.

Really only #2 seems a bit different, and when I installed it all I did was put the cap in, tap it in place with a rubber hammer and tighten it, and I didn't have any issues with that bearing last time round. This I should just leave it be and continue building? lol
 

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just ask for engine assembly blood at your FLAPS!

stuff is like ATF and 80w/90 hooked up in Vegas
 
moper said:
Anyone who says they've never done something wrong out of ignorance or (worse yet) excitement is lying...lol.
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Ha! Speak fer yerself.


....now where's my bfh?

LOL
 
DartVadar said:
So there are a few issues that I know of. One of those is there was constantly little pieces of copper in the oil, slowed down as I changed the oil, but I figured it out once I took the heads off. It goes back to the issues with ootb eddy heads, the springs gouged into the little copper shim under the spring that should have been a hardened cup or something, one bearing actually had some pieces of crap on them and stuck in the tangs, not going to blame the heads completely though, Im not sure where the rest of the crap came from, thought I was really clean when I put it together.

All this happened after the line hone, and the motor is a 360 with about 3k miles on it, I know with that little miles the bearings should NOT look like that. I looked more into it and I dont actually think that my crank was even polished, I looked at my receipts and found nothing for that, but it was really nice when I got it (I thought), and I doubt it was done for free lol

The bearings could be too tight, I have no idea how that happened there though, I measured with plastigauge, but mustn't have done something right (first time ever using it).

When I put it together I just used engine oil, and before I started it I primed the oil pump. I wasn't aware that I needed to coat the bearings with more than that. Would cleaning the hell out of the block/crank, using the right assembly lube and ensuring that the bearing clearance is enough after the crank was turned fix the issue?

Thought I was really careful with this build, I guess not though, was my first time building a motor.

Now just to remind you guys the third picture is NOT mine, only the first two are, I just used that picture I found to easier see the wear pattern that I am talking about.
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Seems like your crank was not balanced correctely, if it was mine the firrst person id roust would be whoever machined it all, sanity check with them and your receipts make sure something like that wasent overlooked. All you can do is retrace your steps, mesure, and cross your fingers. Best of luck
 
InItSwingIt said:
Seems like your crank was not balanced correctely, if it was mine the firrst person id roust would be whoever machined it all, sanity check with them and your receipts make sure something like that wasent overlooked. All you can do is retrace your steps, mesure, and cross your fingers. Best of luck
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Everything is good with the crank now, I don't even know what else to check at this point, basically the only think now I am wondering is about my mains caps.
 
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