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how do u know when u have a spun bearing

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Old 06-18-2006, 10:24 PM
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Default how do u know when u have a spun bearing

hey not sure how u spell it but exactly how do u know when u have a spun bearing?i mean i never have seen metal in my oil,but then i have never cut open one of my oil filters either.i do u have a knock but it may be vavle train not sure.if i open my hood i only hear the knock a bit,if i close the hood and look under the car i can hear it very good.i mean at idle i have 20-30 psi of oil looking at the gauge cluster about 40 psi cold start and like 45 psi around 3k- 6k rpms.im kind of scare because to rebuild a ls1 is pretty pricely.OHH CAR HAS 110K MILES ON HER
Old 06-18-2006, 10:28 PM
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typically there will be a loss of oil pressure associated with it, and from the one ls1 i've seen with a spun bearing it was like 15-20psi most of the time and it had a terrible skweaking (sp?) during idle etc.

on another note, doing a stock rebuild on your motor with new bearings, rings etc and keepign stock rotating assembly isn't all that pricy anymore, probably could get it done under $750 if you reuse stock parts and replace bearings/rings.
Old 06-18-2006, 10:32 PM
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well as i stated i do have a knock,and my oil psi is normally at 20 in idle and in gear.and will a spun bearing damage the crank or anything else?maybe my oil pump can be weak due to the 110k miles on the engine?
Old 06-18-2006, 10:34 PM
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i would think the oil pump might be getting to the point of death. a spun bearing can kill the crank, thats why i say if you think there is a problem that you should start making a plan of action asap. if you have another mode of transportation that makes it easier so you can have the motor pulled and rebuild and not have to do it super quick and mess something up. good luck, hopefully some others with more knowledge and experience with this will post up.
Old 06-19-2006, 02:45 AM
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You could spin a rod or a main. You'll have to check them visually to be sure. If a bearing spun you're going to have journal damage at that location. I'd hate to think an LSX oil pump is only good for 110K. You should be able to get a lot more than that. Your pressure seems low compared to most LSXs. Did the pressure drop slowly over time or was there a sudden drop to your current level? Either way it's not good and bares looking into. No sense putting in new bearings without fixing your oil pressure problem.
Old 06-19-2006, 02:53 AM
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When my 98 ls1 had low oil pressure like you describe I spun a bearing, it was #5 rod. We fixed the spun bearing and found out the oil pump was shot because the valve had stuck, which is what finally killed my bearing.
Old 06-19-2006, 03:50 AM
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Originally Posted by Boostaholic
When my 98 ls1 had low oil pressure like you describe I spun a bearing, it was #5 rod. We fixed the spun bearing and found out the oil pump was shot because the valve had stuck, which is what finally killed my bearing.
I'm guessing you mean intake/exhaust valves?

Anyone got a pic of a spun bearing? My bearings look a little worn, but I just dont know if I should replace them or not. I'm pretty sure bearings are cheap.
Old 06-19-2006, 07:08 AM
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a spun bearing will look burnt up and you will definitely know something aint right.i've seen a couple that were just eat up alittle but that is because the motors were cut off immediately.
Old 06-19-2006, 09:59 AM
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Originally Posted by ezrollin
I'm guessing you mean intake/exhaust valves?

Anyone got a pic of a spun bearing? My bearings look a little worn, but I just dont know if I should replace them or not. I'm pretty sure bearings are cheap.
Bearings are about $2.50 per rod, and no I mean the valve in your oil pump with that little spring, i believe they call it a relief valve.

Also, a spun bearing is just a bearing that has "spun" from the top side down and bottom side up, or around more than that in extreme cases. It is caused by worn bearings from low oil pressure or too much clearance between the crank and a bearing.
Old 06-19-2006, 10:33 AM
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you might need to just replace the oil pump and o-ring. When i installed a new pump on my car after a cam install i only had 18-20 psi due to re-using the old o-ring. My lifters would lose there prime and the engine would knock. You need about 35 psi + in order to keep them things pumped up.Plus i heard 98 model oil pumps are known to go bad
Old 06-19-2006, 03:17 PM
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well how long will an engine last with a spun bearing?and my oil pressure has pretty much been the same seens i bought the car a year ago,but then it didnt have the knock and now it does
Old 06-19-2006, 07:23 PM
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i curently have a spun bearing,probably rod,and it is non driveable.it only runs when you pat the gas,i'd say because the knock is making knock sensors go crazy and my oil pressure is much less than it was.if you have a spun bearing it will be very audible.you may have lesser problems hopefully.
Old 06-19-2006, 07:45 PM
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well i hope so.will a spun bearing damge a new set of lifters? i mean i will put a new oil pump in along with the lifters and cam
Old 06-19-2006, 08:25 PM
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my "uneducated" guess would be probably not,the shavings from the bearing,if that is what the problem is, should get flushed into the oil pan and trapped in the filter if they make it that far.is your knock actually a clunky knock or a ticking sound ?
Old 06-19-2006, 08:29 PM
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mine spun #6 rod lower bearing was on top. with the top bearing never seen that and i have been a gm tech. for 15 years. and the piston was bearly hitting the head. just save the head if keep driving would have caused major problems. now have a tsp short block.
Old 06-19-2006, 08:36 PM
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I'm struggling with this issue with my LT1. It has a knock and it seems to be getting worse. It's definitely louder when the engine is cold, too. I can't decide if it's a piston knock or a rod bearing. I can fix either without pulling the engine, but I can't even tell which bank it's coming from.

Oil pressure hasn't changed.
Old 06-19-2006, 09:18 PM
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ticking
Old 06-19-2006, 09:51 PM
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When i spun a rod bearing it also bent the crank and the two bearings were spun into one
Old 06-19-2006, 11:28 PM
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okay wouldnt a bend crank cuase losts of vibration
Old 06-20-2006, 01:35 AM
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When the bearing gets spun the locator tabs get broken off and you will see wear marks on the bearing and journal. Of course if you have two bearing stacked up on top of each other on one side and none on the other that pretty much is a dead giveaway a bearing has spun and somehow wedged itself between the other bearing and the journal. That ain't easy to do considering the Law of Impenetratability says two objects are NOT supposed to be able to occupy the same space at the same time. The bearings are cheap and easy enough to change. The pan is probably going to be the hardest part. You need to examine the journals of the spun bearing very closely for wear and pitting. This sounds like a used car you bought that had problems when you got it. You might consider Plasitigage. A new "O" ring at minimum if not a new pump. You can shim the spring on the pressure relief valve in the pump.


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