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New Motor - Gold Specs in oil looks metallic and gold specs in filter

10K views 67 replies 15 participants last post by  callmewaylon 
#1 ·
Newly rebuilt by me motor - 400 chevy, crank .020 under, bored .040 over, flat tappet cam that was previously broken in. Fired it up and warmed it up for 20 or so minutes and changed the oil and filter. They both looked fine. Then I put 150-200 miles on and changed it again. Oil has a slight metallic swirl to it. Cut open the filter and it has gold specs in the pleats. Nothing big like flakes, more like gold dust. The only thing I can think of is that the crank end play wasn't quite what I would have liked to see. It was .002. I could get it to move .004 but as soon as I let off the pry bar it went back to .002. Maybe the thrust bearing is wearing off? Any ideas? Any chance it's not eating the bearings? What does oil normally look like after a rebuild?
 

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#7 ·
While it is very difficult to make a recommendation from a low res picture on the internet, your description and images indicate imminent catastrophic bearing failure.

Last time I seen one this bad was a string of engines sent back for warranty return due to bearing failure after rebuild. Upon teardown it was determined the reground cranks had been micropolished in the wrong direction after grinding to size caused by one employee incorrectly trained on which way to chuck the crank in the grinder. By the time we discovered the error over 100 engines had been sent out and already installed in customers cars, all of the cranks removed from these engines looked fine but the bearings were all worn into the copper plating.

Simple mistake, huge consequences.

Tear it down and find out why now, assume the engine needs a complete cleaning to remove particulates and lifters tossed because its not worth it to recondition. Usually everything else can be saved but the disassembly needs to be total.

Sorry for the bad news but that is a seriously intensive particulate contamination for the mileage and copper is the worst thing you want to see.
 
#12 ·
That's a lot of material it looks to be bearing. .002 is on the tight side of GM spec for thrust. Question would be if the thrust face on the crank was touched or only the journal? It is pretty common to see the thrust face buggered up if they touched it this is harder to machine properly than the journals. It is also harder to set up properly on assembly. It is easy to have the upper and lower not match which messes up the oil flow on the faces leading to this type of failure. Not that this is the only cause but it is pretty common.


Bogie
 
#13 ·
I did set the thrust bearing by several good smacks on the crank snout with a dead blow and then on the flywheel side. It should have been lined up. The part that bothered me is that I had .005-.006 crank endplay before I tightened the rear cap down and only .002 after. I tried it a bunch of times and that's the best I could get. Probably should have stopped and taken it back to the machine shop but the low end clearance was .002 so I figured I could squeak by. Any chance the thrust bearing could just be clearancing itself a little and it will be fine?
 
#14 ·
Your only fix at this point is take it apart. Something is seriously wrong and sticking your head in the sand and pretending "self clearance" is a legit fix your in for a expensive and disappointing nightmare. I'm not trying to be an *** it's just I hate to see what could be salvageable get real expensive real fast!!
Mostly likely all the bearings are torn up. If you continue to run it anyway it's gonna spit out a bearing, the piston will hit the head and shatter, the loose end of the rod will tear a hole in the cylinder and you'll end up with nothing but a heart ache and disappointment.
 
#15 ·
You should stop running that engine and hope the wiped out bearings did not take the crankshaft with them. The crank may be salvageable by having it turned down undersize and matched to oversize bearings with the proper amount of oil clearance.

I rebuilt a 1967 Firebird 400 engine and it had glitter in the oil in less than 50 miles. We tore it down and determined that the shop that turned the crank and supplied the bearings apparently did not allow proper rod and main oil clearances or they used the wrong size bearings when they assembled the short block. The shop never admitted fault but corrected the problem anyway. . We plastigauged the crank before assembly the second time and made sure the rod and main oil clearances were correct.

Lesson learned:
Never take someone else's word for the rod and main bearing clearances. . Check the clearances with a plastigauge.
 
#16 ·
I had the machine shop measure bearing clearances for me plus I plasti guaged them just to be sure. Like I said, the only clearance I didn't like was the crank end play. Thinking I might just drop the pan and see what's going on in there. I've already had this motor in and out of the truck 3 times so I'm getting pretty good at it if that's what it comes to.
 
#17 ·
This would be better than running it to failure which is likely to get something else expensive when that happens.


Sometimes builds go sideways, it just happens usually when a sign gets missed the big one I can see is when there was a change in end play when the rear main was torqued up. Another way of looking at is there is no point to measuring end play till that cap is torqued and then you may find this becomes a repetitive task for a while till it's determined that the measure is on target or not. This probably the hardest thing to get right when dropping in the crank.


Bogie
 
#18 ·
Well, I finally got some time to yank the motor out of the truck. Rear thrust bearing is wearing. Crank end play is now .014. Rear main bearing looked the worst but really not too bad. The thrust surface was the worst. Rest of the mains were pretty good. Minor copper showing on a few but none look like they are decinigrating. Rod bearings looked perfect. Big question is what to do now? What caused the thrust bearing wear. Clutch was properly adjusted, Pilot bearing looks good with no abnormal wear.

Auto part


Metal Rim Copper Brass


Hand Auto part Finger Bearing Wheel


Metal Auto part Brass Bearing Tin


Auto part Metal Copper
 
#26 ·

What do the upper shells look like?


If you don't see the pinch wear pattern that's on the cap side of the bearing shells it probably is the caps were end dressed after the line bore/hone or the caps were end dressed and the line bore/hone wasn't performed.


This also goes for the shells if caps had the ends dressed the shell also need the same relief or they will pinch in a pattern much like the ones I see here. The same would apply to the thrust surfaces of the bearing it would develop a warped surface. Unless you measured for clearance in this direction with the caps torqued but no shaft so you can get a micrometer in there this is something you or anyone else would see. It isn't much of a pinch but it sure looks like that is what it is. Could be an error in the manufacture of the bearing shells but you'd see that failure/high wear on both the uppers and lowers.


I guess the term I'm hunting for would be "too much crush" regardless of where it comes from.



Bogie
 
#23 ·
That looks like the main bore are out of round or the crank journal is out of round either by bad machine work or something your doing is pulling the caps out of round when you tighten them up. Verify with a bore gauge and mics.

Bolt vrs studs,
torque wrench isn't accurate and repeatable
your not using it properly
oil pump bolt too long
improper machine work
dirt or assembly issues

All areas to look at it.
 
#24 ·
Crank was driven to the machine shop by me. Ground .020 under and checked for staightness. ARP main bolts. Machine shop honed the mains for ARP bolts because they told me it needed it for the ARPs. I don't think they line honed it. I remember questioning it at the time.

The most troubling part is the thrust bearing going bad and end play opening up to .014. The rear thrust surface on the rear main is being eaten away. After some research I believe it is due to lack of polishing on the rear thrust surface of the crank. Can still see faint swirls from grinding. I have read this can act like a windshield wiper and remove the oil film. The clutch was adjusted properly and the trans input shaft went into the crank properly so I know that did't do it.

Machine shop said they'd repolish the crank thrust surface. I'm thinking maybe I should have the block line honed as well but not sure if it's needed.
 
#25 ·
If they honed the mains, then they line honed it, or perhaps the line bored them. Either way the main line should be straight.
You may have to sand down the thrust bearing to get enough clearance, use a piece of 600 sandpaper lubed with AFT on a piece of glass or a some other really flat surface. Sand the front side of the thrust surface to get the clearance you want.
On 400 blocks, I used to drill a hole through the thrust surface of the main cap into the oil passage from the pump, then drill a .030 hole through the main bearing to intersect the first hole, forcing oil pressure to the rear of the thrust due to the problems with thrust bearing failure.
 
#27 ·
Engine had 2-300 miles on it at tear down. The crank rolled over just fine once the mains were torqued. ARP main bolts are stock size. The thing that made me nervous at assembly was that the crank end play wend from around 5 or 6 thousandths with the bolts just snug down to 2 thousandths once torqued. I have read that might mean the cap is cocked. I tried it over and over and went through setting the thrust bearing process several times always with the same result. Tore the motor down all the way tonight and the block and crank are going back to the machine shop tomorrow. They are going to check the line bore and the thrust surface. I think it needs to be because it still shows some of the swirls from grinding and I think that is killing the oil film. Took more pics but don't have time to post them tonight. I will keep posting on this until it comes to a resolution. Thanks for your ideas and input.
 
#31 ·
I'll repeat for you what I responded to Mr. Compton with which is the following:


I don't think it's off by that much but just enough to result in fast and abnormal wear. My rough guess would be the use of ARP studs. Either the studs weren't torqued to ARP requirements or improper lubrication was used at the time of the align bore/hone; or the ARPs were added and used after the align bore/hone had already been done using OEM bolts.


Additionally I'll comment to the thrust surface of the crank that you mention that it has swirls, this can be a contributor depending on how deep the swirls are. A visual swirl pattern is not uncommon but is one you can't feel these are passable. A swirl pattern that catches your fingernail or an edge wiggler or even feels by touch is too rough. The thrust faces of a crankshaft are always a problem to dress it takes care and time to do properly. This is not work for an apprentice.


What do the upper bearing shells look like are they damaged like the lowers? What I'm driving on here is too much bearing crush that distorted both the lower and upper shells. Or is the damage confines to the lowers?


Overall this isn't off by much but it is off. I doubt this would be felt by crank rotation, but the wear pattern looks a lot more like the bearings have 200,000 miles on them not 200 miles. A good machinist could spot this when mic'ing the installed shells (probably another missed step in the process of aligning the saddles).


Bogie
 
#28 ·
Thrust clearance should be 0.005"-0.007" not 0.002"!!! you answered your own question.

Should never have assembled with the thrust clearance that far out of spec.
 
#29 ·
That Craptastic machine work right there.

On SBC 400's, the rear main seal has shoulder that has to be cut off in a mill to get the hone through it. If it's still there and your using the stock seal, same as the 350ci, and not seal number 91010233 or the Felpro equivalent NO work was done or they really screwed it up their machine trying.

Since the bores are almost never round anyway, you have to cut a few though off the caps mating surfaces and cut or hone to fit the bore you want which depends on the crank journal sizing.
First pic that shows the cap mating surface HAS NOT been touched.

Rear main cap is to tight on the rear most side. Oil pump bolt wasn't bolted on either which pulls the cap out of round as evident by the bearing wiping.

Thrust is way small because the cap wasn't fixed or machined square to the bore. This will not likely show up on the plastic string or even a bore gauge unless your checking both front and rear for taper. Your crank could have taper too for that matter. Most likely at least some in the range of .0005 or so on those steel cranks.

Since the bores aren't round or inline with the cam tunnel then why would you expect this thing to stay together?

I wouldn't be returning anything to those people. Doing it twice is 3 times more expensive.

At this point you might as well splay it as the cast caps aren't the best anyway. Did the engine guy call and ask what torque value your using? Did he ask for the oil pump and bolt or stud?
If not, that's another scary sign.
 
#33 ·
Yeah, I wasn't real happy about the "shrink up" comment, but they are a well respected shop in this area and the guy is genuinely working with me. I think sometimes people just get away with doing things like this for a long time when it really shouldn't work. Why bother just running the hone through the bores without taking anything off the caps? Made it sound like they were saving me money but if they would have asked I would have said just go ahead and line hone it.
 
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