Does this thrust bearing seem "fine" to you?
06-21-2013, 01:36 PM
#1
Staging Lane
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Does this thrust bearing seem "fine" to you? Because that's what the shop who built my engine just told me over the phone after doing a teardown on it.
Here's the condensed version of the story:
- Recently had my motor rebuilt
- After only 12 passes and a few hundred street miles the #3 rod bearing seized at the track to the point where the motor wouldn't even turn over without spark plugs in it
- Before taking the motor back to the shop, I noticed that my crank seemed to have a little too much end play so I pulled off the center main cap and saw how badly worn the thrust bearing was
I should note that before assembling the motor the shop noticed an issue with the thrust bearing area on the crank and sent it out to be repaired prior to assembling it in the engine.
When I called to see how much (if any) responsibility they would be taking for a motor that seized up so quickly, they said the thrust bearing looked perfectly fine and when I pressed them on that statement, he backed off a bit saying something along the lines of "well maybe he was looking at the wrong one".
While I'm no expert on the subject, I think it's pretty clear that the thrust bearing isn't fine and it appears as though the crank shop didn't do the repair properly. On the front side of the bearing, not only is the center "divot" (not sure what the proper technical term is) pretty much completely gone, the wear pattern is different than the ones to the left and right of it. You would think that if the crank was flush with the bearing surface it would have worn equally but instead it almost looks like it was warped similar, to a brake rotor that overheats and ends up with a high spot.
Any thoughts? I'm going to be calling them again this afternoon and I'd like to gather some opinions beforehand if possible.
Front
Rear
Here's the condensed version of the story:
- Recently had my motor rebuilt
- After only 12 passes and a few hundred street miles the #3 rod bearing seized at the track to the point where the motor wouldn't even turn over without spark plugs in it
- Before taking the motor back to the shop, I noticed that my crank seemed to have a little too much end play so I pulled off the center main cap and saw how badly worn the thrust bearing was
I should note that before assembling the motor the shop noticed an issue with the thrust bearing area on the crank and sent it out to be repaired prior to assembling it in the engine.
When I called to see how much (if any) responsibility they would be taking for a motor that seized up so quickly, they said the thrust bearing looked perfectly fine and when I pressed them on that statement, he backed off a bit saying something along the lines of "well maybe he was looking at the wrong one".
While I'm no expert on the subject, I think it's pretty clear that the thrust bearing isn't fine and it appears as though the crank shop didn't do the repair properly. On the front side of the bearing, not only is the center "divot" (not sure what the proper technical term is) pretty much completely gone, the wear pattern is different than the ones to the left and right of it. You would think that if the crank was flush with the bearing surface it would have worn equally but instead it almost looks like it was warped similar, to a brake rotor that overheats and ends up with a high spot.
Any thoughts? I'm going to be calling them again this afternoon and I'd like to gather some opinions beforehand if possible.
Front
Rear
06-21-2013, 03:58 PM
#2
I know this post is against a machine shop who does it for a living, so take my opinion/experience with a grain of salt.
Based on what i see - overheating discolourations. Marks that also look like pitting which can be interpreted as a sign of overheating. For a motor that was freshly built i would assume there was a mistake made in assembly tolerances. What break in method was used? Was the motor blueprinted? Also with thrust bearing failures make sure give the entire motor a one over. Particles that get into your oil due to rubbing only exacerbate the problem and can extend throughout the motor and into the heads.
Based on what i see - overheating discolourations. Marks that also look like pitting which can be interpreted as a sign of overheating. For a motor that was freshly built i would assume there was a mistake made in assembly tolerances. What break in method was used? Was the motor blueprinted? Also with thrust bearing failures make sure give the entire motor a one over. Particles that get into your oil due to rubbing only exacerbate the problem and can extend throughout the motor and into the heads.
06-21-2013, 04:01 PM
#3
Staging Lane
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I know this post is against a machine shop who does it for a living, so take my opinion/experience with a grain of salt.
Based on what i see - overheating discolourations. Marks that also look like pitting which can be interpreted as a sign of overheating. For a motor that was freshly built i would assume there was a mistake made in assembly tolerances. What break in method was used? Was the motor blueprinted? Also with thrust bearing failures make sure to check your main caps for wear. Particles that get into your oil due to rubbing only exacerbate the problem and can extend throughout the motor and into the heads.
Based on what i see - overheating discolourations. Marks that also look like pitting which can be interpreted as a sign of overheating. For a motor that was freshly built i would assume there was a mistake made in assembly tolerances. What break in method was used? Was the motor blueprinted? Also with thrust bearing failures make sure to check your main caps for wear. Particles that get into your oil due to rubbing only exacerbate the problem and can extend throughout the motor and into the heads.
As for breakin, I ran conventional 5-30 for the first 150 miles and then switched over to Mobil 1 5-30.
06-21-2013, 04:17 PM
#5
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I would put it back together and check the end play and get a new bearing to compare the two. The center notch in the front of the bearing appears that it is just made different from the rest for whatever reason. It doesn't look like it is V shaped like the other ones. The crank turns so even if they machined it wrong it would wear the bearing the even the whole way around.
06-21-2013, 04:31 PM
#6
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I'm not sure as I don't have the build sheet with me at the moment.
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06-23-2013, 10:05 AM
#8
I see/read all the time when people spend the time and money to rebuild their engines and skimpout (IMHO) and don't properly prime their engine. I know GM supposedly says to spin it, but thats just asking for some sort of damage.
Do yourself a HUGE favor once you get this engine fixed and make a primer like CARCRAFT did using a 5 gal bucket and SBC oil pump . I bought a Engine Quest preluber mentioned in the mags and it was a pc of junk. Way too had to fill, runs out way to soon and requires repeated refills to get all rockers pissing/bleeding oil. I built the bucket/SBC oil pump for 1/4 the cost.
Do yourself a HUGE favor once you get this engine fixed and make a primer like CARCRAFT did using a 5 gal bucket and SBC oil pump . I bought a Engine Quest preluber mentioned in the mags and it was a pc of junk. Way too had to fill, runs out way to soon and requires repeated refills to get all rockers pissing/bleeding oil. I built the bucket/SBC oil pump for 1/4 the cost.
06-23-2013, 04:41 PM
#10
+2
I was always told to minimize the number of times a motor is turned over completely (to no more than 3 if possible) during rocker setup to prevent wiping assembly lube from critical bearings, camshaft, lifters, etc.
I was always told to minimize the number of times a motor is turned over completely (to no more than 3 if possible) during rocker setup to prevent wiping assembly lube from critical bearings, camshaft, lifters, etc.
