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  #1  
Old 06-06-2005, 01:27 PM
And87mnr And87mnr is offline
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Default Shavings

I've put about 3900 miles on a freshley rebuilt engine and am having some concerns. I change my oil about twice a month and have noticed metal shavings covering my magnetic oil plug. Looks like a porcupine. I undersand some shavings in the oil after a rebuild maybe the 1st or 2nd change But it dosn't ease up, in fact it's getting worse. And have noticed the idle is slowley deteriorating as well. What could cause this and where should i start looking? Thanks
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Old 06-06-2005, 04:16 PM
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Default Re: Shavings

Hate to say it, but it might be a cam lobe/lifter going south.
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Old 06-07-2005, 09:51 AM
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Question Re: Shavings

Can you describe how your rebuilt motor was broken in? I'm interested to know how the motor was handled at the very first start up after the rebuild. Was the cam replaced? Were new lifters installed? What's your oil pressure at various operating conditions; idle, 2K rpm, etc?

Thanks.
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Old 06-07-2005, 02:53 PM
And87mnr And87mnr is offline
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Default Re: Shavings

Thanks for the inquiries. The motor was broken in by doing moderate (~ half throttle) accelerations from medium to high RPM over and over, And a few WOT blasts the first 100 miles. The next 200 miles the rpms were kept below 3500. All of my clearances are very tight due to dry film coatings on all bearings and piston skirts. A HV oil unit was used with this rebuild so pressure is real high. Almost too high. Idle right now is 28PSI fully warmed up, and 3100 rpm it's @ 78PSI (cruising@100mph). New cam along with the rebuild and new lifters as well.

Last edited by And87mnr; 06-07-2005 at 03:19 PM.
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Old 06-07-2005, 03:00 PM
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Question Re: Shavings

I was specifically interested to hear how you broke in the new cam. The usual procedure is to run the engine at 2000-3000 rpm for 20-25 minutes on the very first start up.

Was this done?
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Old 06-07-2005, 03:28 PM
And87mnr And87mnr is offline
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Default Re: Shavings

Well the cam was broken in by holding the RPM's at 2500 rpm for ~15-20 minutes.
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Old 06-07-2005, 03:41 PM
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Question Re: Shavings

Who manufactured the cam shaft?
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Old 06-07-2005, 03:43 PM
And87mnr And87mnr is offline
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Default Re: Shavings

Comp cams is the manufacturer.
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Old 06-08-2005, 10:30 AM
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Default Re: Shavings

I guess it could be a lobe or lifter, but it is a new cam . Other than tearing it down again are there any tests i can try or anything i can look at to better narrow down the possibilities?
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Old 06-08-2005, 03:55 PM
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Default Re: Shavings

Quote:
Originally Posted by And87mnr
I guess it could be a lobe or lifter, but it is a new cam . Other than tearing it down again are there any tests i can try or anything i can look at to better narrow down the possibilities?
If the shavings are magnetic, then I'd be concerned and pull the valve covers and measure lift on each rocker arm. You can do this with a dial indicator and magnetic base and measure at the point the rocker contacts the pushrod. You're looking for total lift and for one that is significantly different than the others. Make sure you run the motor a bit (so lifters are pumped up) before doing this.

That could point out an obviously bad cam/lifter.
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2006 Trailblazer SS Red Jewel Tint 395 HP AWD (sold)
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