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help, spun cam bearings, or spun main bearings

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Old Oct 19, 2007 | 02:19 AM
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Default help, spun cam bearings, or spun main bearings

Just finished up a little while ago with KBs motor swap. Had a little trouble getting oil pressure, but after it was fired up, instant pressure, 40+

now the question, it knocked a little, (no tapping, or clacking, just a hint of hitting an extension on the side) and went away after the second 15 min cycle. I started it up, ran it for 5 minutes, and held it at 1,000. Waited 10 or so something minutes, 4 radio songs later. Cranked it again, and a whining sound started. It would only come on at low RPMs. Once it was off idle, it went away.

Now on the third start, it's pretty obvious, and doesn't go away until 2K or so. It sounds like a roots style blower, . . .noticeable or loud at idle, and gets more faint as you rev it.

KB and I both could not remember if we tightened the cam plate, but we're sure that he did the cam bolts right. Any ideas? We took a vid.

Full ARP bottom end, stock bottom end block with 14K something miles on it.
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Old Oct 19, 2007 | 02:44 AM
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why did you rev the motor for 10minutes?
if the bolts on the bottomend werent tightned properly you could have issues
if your hearing sounds, check the dipstick for shavings also for reasurance drain the oil and cut out open the filter to see if you have shavings. if you have shavings time to rebuild that motor
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Old Oct 19, 2007 | 08:28 AM
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Thanks for the reply, I do know for sure the cam bolts were torqued down correctly...but I honestly don't remember the cam plate. I sure hope that's the problem. I'm trying to get the video uploaded, but I've gotta find a firewire card..
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Old Oct 19, 2007 | 08:47 AM
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Originally Posted by Quik
why did you rev the motor for 10minutes?
if the bolts on the bottomend werent tightned properly you could have issues
if your hearing sounds, check the dipstick for shavings also for reasurance drain the oil and cut out open the filter to see if you have shavings. if you have shavings time to rebuild that motor
I ran it for 5 minutes the first time, and then let it cool off, for 10, then ran it again for another 15. Of the first 15 minutes, the sound was gone after the first minute.

I checked the oil stick and nothing but oil. It sounds more like a pissed off squirrel at a feeder. It's very low pitched, with no screeching. Anything past 1,600 - 2K, and the noise it gone
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Old Oct 19, 2007 | 08:55 AM
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If the cam plate is loose your oil pressure would be low since it seals the cam oil channels.
Cut the filter apart on the sides just under o ring and check the filter element for material.
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Old Oct 19, 2007 | 09:09 AM
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Originally Posted by TurboGibbs
If the cam plate is loose your oil pressure would be low since it seals the cam oil channels.
Cut the filter apart on the sides just under o ring and check the filter element for material.
well there's 40+ with 5w-30
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Old Oct 19, 2007 | 09:12 AM
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Or if you KNOW something isn't right just go ahead and pull it and fix it. Or if it's 2wd you can drop the crossmember under the engine and pull the pan pretty easily.
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Old Oct 19, 2007 | 09:23 AM
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Originally Posted by TurboGibbs
Or if you KNOW something isn't right just go ahead and pull it and fix it. Or if it's 2wd you can drop the crossmember under the engine and pull the pan pretty easily.
not looking forward to that . . . can you pull the crank with the pistons in the block?
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Old Oct 19, 2007 | 09:36 AM
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I listened to it this morning (they're doing the work in my garage). I would describe the sound as a chirping sound. No grinding, tapping or knocking.

I've never heard a spun bearing before, but I guess that it could be that. Can anyone describe what a spun bearing sounds like?
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Old Oct 19, 2007 | 09:58 AM
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Originally Posted by Tootall
can you pull the crank with the pistons in the block?
Yes, You just have to push a few pistons up closer to the deck to get the out of the way after you unbolt the rods.
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