View Full Version : Shavings

06-06-2005, 01:27 PM
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

06-06-2005, 04:16 PM
Hate to say it, but it might be a cam lobe/lifter going south.

06-07-2005, 09:51 AM
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. :(

06-07-2005, 02:53 PM
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.

06-07-2005, 03:00 PM
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?

06-07-2005, 03:28 PM
Well the cam was broken in by holding the RPM's at 2500 rpm for ~15-20 minutes.

06-07-2005, 03:41 PM
Who manufactured the cam shaft?

06-07-2005, 03:43 PM
Comp cams is the manufacturer.

06-08-2005, 10:30 AM
I guess it could be a lobe or lifter, but it is a new cam :confused: . 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?

06-08-2005, 03:55 PM
I guess it could be a lobe or lifter, but it is a new cam :confused: . 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.

06-08-2005, 05:03 PM
Thank for all the help. I will keep everyone posted on the status and or results.

06-10-2005, 09:01 PM
Being an engine builder, but not incredibly familiar with Buick V-6's in general.....

Ken Mosher makes a good point. Measure the cam lobes. If you're worried about the lifters pumping down when trying to measure how much lift the cams gives your magnetic dial gauge, then remove the rocker arm shaft. It'll remove the pressure against the valve springs, so then you can get a dead nuts valve lift measurement.

I know from other engines, mysterious metal sometimes equivicates into a worn thrust bearing. And a worn thrust will not effect oil pressure, at least not right away.

Again.... not sure if you can use the same "trick" as you can on a chevy motor, but closing off the oil filter by-pass is a good idea also. Run a fram HP filter, so then you can keep the metal trash from recirculating in the engines oil.

I once had a GN that someone supposedly rebuilt the engine on towed into my shop. Engine had no oil pressure when hot and metal in the oil. Come to find out the guy that added on one of these "hi-volume" oil pump kits didn't clearance the spacer to clear the gears properly. So the engine started to circulate the metal shavings.

Hope this helps,