I'm gonna sound like a newb

[95TransAm]

But in a sense, compared to most of you, i probably am
I've never gotten a straight forward answer to this, and i came across this statement again and i want to know what it exactly means.

When someone says they "spun a bearing", what exactly has happened. Like i said, i've gotten arbitrary answers, but am curious to what exactly is happening when this happens.

Thanks for takin time to help out the newb

[TraceZ]

The bearing fault is caused when metal touches metal. Low oil pressure can cause it, or foreign materials in the oil can cause it. Many times the bearing will completely disintigrate and end up sitting in the oil pan in chunks. It really depends on how long the motor runs after the initial damage takes place. If the motor is left to run long enough after initial failure a spun rod bearing will actually result in failure of the rod. Typically if 1 bearing fails, the others are shortly behind it because the metal shavings will contaminate them all.

The term "spun" is an early stage of failure where one of the halves of the bearing actually crawls under the other half and begins to spins around the journal. This produces much heat and friction until the entire bearing is nothing but metal shavings.

[wolfdogs]

The bearing fault is caused when metal touches metal. Low oil pressure can cause it, or foreign materials in the oil can cause it. Many times the bearing will completely disintigrate and end up sitting in the oil pan in chunks. It really depends on how long the motor runs after the initial damage takes place. If the motor is left to run long enough after initial failure a spun rod bearing will actually result in failure of the rod. Typically if 1 bearing fails, the others are shortly behind it because the metal shavings will contaminate them all.

The term "spun" is an early stage of failure where one of the halves of the bearing actually crawls under the other half and begins to spins around the journal. This produces much heat and friction until the entire bearing is nothing but metal shavings.

my comp's lt1 is living proof of what he just said.... #8...

[raroZ28]

That's why keeping fresh oil is so important. Most people don't realize... I see people all the time, people that buy cars just for transportation. Enthusiasts like us understand the importance of a quality oil change. People like my bosses and co-workers go get a $10 oil change after about 5000 miles. That's why engines don't last long, and a lot of people think 100K is a lot for a motor. Man, that's just broken in if it's properly taken care of. Take care of a motor and it'll take care of you. If everybody changed their oil religiously like I did, I'm sure engines would last a lot longer... I feel bad for whoever gets my boss' malibu after his lease is up Buddy's bro had a 2 year lease on his F-150. Didn't change the oil once the entire time.

I had a spun bearing before, it isn't pretty. The bearing fell out of the rod, got all chopped up by the crank. When I took off my oil pan there were particles all over the pan, it was minced. Looked like something a blender couldn't even do.

[WICKED LT1]

The main bearings are semi-circular pieces of metal (likely to be some babbit alloy) that line the area where the crank rotates inside the block. When everything is working normally, there is a very thin layer of oil trapped between the spinning crank and the bearing. Crank moves, bearing doesn't, it's trapped by the block. When that layer of oil is interupted for whatever reason, the crank contacts the bearing and heat is produced. When the bearing gives up, it will either weld itself to the crank, and then spin inside the block opening, or just begin to disintigrate and allow the crank to hit the block. This is what produces that amazingly bad noise that tells you something has gone horribly wrong. Same principle for the rods, just isolate the crank from the connecting rods. Hope that helps.


-Paul

[95TransAm]

Hey thanks as always guys. Just one more thing that i can be that much more knowledgeable when it comes to cars
Looks like one more reason that makes me glad i change my oil religiously with good oil and a good filter

[wolfdogs]

Hey thanks as always guys. Just one more thing that i can be that much more knowledgeable when it comes to cars
Looks like one more reason that makes me glad i change my oil religiously with good oil and a good filter

keep an eye on that oil pressure gauge too. in my case, i changed my oil every 3k with mobile one..and filter..

my lt1 had one of those "1 in 3000" or something like that, oil pumps in which the shaft developed a hairline crack at the mounting base... this alowed the pick up portion in the pan to "tilt" under accelertion.... as the crack worsened.. the tilt angle became more... so for a bried nanosecond... it sucked air under 3/4 accleration leaving my gas station on the way home one day... that sicking sound i heard told me what happend... i drove home below 3k rpm and took it to the dealer the next day. the motor was rebuilt under warranty... but i paid extra and we used all gm hp parts this time....

watch the oil pressure ... if you see fluctuations on acceleration..you may have that problem...thats the pick up moving around.

[95TransAm]

keep an eye on that oil pressure gauge too. in my case, i changed my oil every 3k with mobile one..and filter..

my lt1 had one of those "1 in 3000" or something like that, oil pumps in which the shaft developed a hairline crack at the mounting base... this alowed the pick up portion in the pan to "tilt" under accelertion.... as the crack worsened.. the tilt angle became more... so for a bried nanosecond... it sucked air under 3/4 accleration leaving my gas station on the way home one day... that sicking sound i heard told me what happend... i drove home below 3k rpm and took it to the dealer the next day. the motor was rebuilt under warranty... but i paid extra and we used all gm hp parts this time....

watch the oil pressure ... if you see fluctuations on acceleration..you may have that problem...thats the pick up moving around.

Thanks for the heads up on that. I always monitor my gauges periodically when I drive, but at least now if something does happen one day, i know how to go about not making it worse.

Also, i was under the impression that when you accelerate, that your oil pressure should increase a lil bit....at least thats what I've been told. Am I wrong here?

[wolfdogs]

Thanks for the heads up on that. I always monitor my gauges periodically when I drive, but at least now if something does happen one day, i know how to go about not making it worse.

Also, i was under the impression that when you accelerate, that your oil pressure should increase a lil bit....at least thats what I've been told. Am I wrong here?

thats correct. underload..the oil pressure goes up. comes down at idle..sometimes as low at 30. so if you see it drop under acceleration...then thats a bad thing..

[raroZ28]

hehehe, i still remember the day... Driving, car started clanking, oil pressure dropped, pulled it home (about a mile). Thing was so hot, radiator hose swelled up like there was a softball in it and exploded, car was smoking like crazy. Always watch your oil pressure, it's the most important gauge you have! I put a mechanical gauge under the hood of my conquest after all that, factory gauges are electrical. Never trust electrical.

[lt1maro]

Cant remember which mark is 30 because mine always sits at the the mark above the red mark or a little above.

[azkkn]

i lost #8 in my 89 Blazer, oil pump pickup fell right off the pump. i drove it 12 miles home, promptly put it in the garage and went and jumped in my dads truck to go get a new motor at the dealer. i knew what the noise was and i knew it had 180k on it.