Shavings in oil pan that are not metal

[1970 skylark 350]

Okay, I have a 1970 Buick Skylark with a 350 engine that has not been taken apart. Until now.

I went to replace the timing chain and repair some oil leaks. I removed the oil pan and after getting it out from under the car I found gray matter in the oil, small particles and some shavings in the sump of the pan that made me wonder if I had a rod bearing going out.

The engine never knocked or had poor oil pressure. The oil I poured out of the oil filter did not contain particles. I removed the intake maifold and the lifter gallery was pretty clean considering this engine is 45-years-old and has 120,000 miles.

Then we examined the shavings. A magnet does not grab. The shavings are thin and soft. We took a mini MAP gas torch and attempted to see how the shavings reacted to heat. The shavings melted immediately and looked like solder. My friend thinks the shavings are lead, but how in the world would lead get into the oil pan?

Everything else seems good. I think I've ruled out bearing failure, but I am still perplexed about these shavings.

Any ideas?

[carmantx]

Could it be parts of the original timing gear? It was plastic.
if the pan has never been off, then small pieces through the years get in the bottom, and build up sludge around them over time. Possibly no bad issues.

[1970 skylark 350]

Well it could be from the cam sproket. It is nylon, or plastic. I haven't removed it yet and I was surprised it was in decent shape. I don't see any broken teeth, but that doesn't mean there aren't any broken teeth. I will know more after I take it off.

These shavings are gray and are very pliable. I have about a tablespoon amount of them. When heated the shavings right away reacted like solder melting.

[telriv]

Usually that heavy gray matter is what's left over from leaded fuel contamination. It settles into the crevices & valleys. I've never tried heat to melt it but I would guess that is what you are experiencing.


Tom T.

[TexasJohn55]

The shavings you describe are likely from engine bearings, question is-which one. Most likely would be crank thrust bearing, measure crank thrust end play first. Cam bearings and crank bearings next for inspection.

[1970 skylark 350]

The shavings are not metal though, John. If it was cam bearings or a thrust bearing the magnet would have grabbed it. I even have a set of new cam bearings and I made sure the magnet worked on them and it did.

I'm starting to think it is old lead contamination. This engine has never been opened up. We removed the intake manifold and checked around the cam bearing areas and around the cam. There were no shavings or debris around the cam and in the lifter gallery.

I'll keep looking to make sure, but this stuff dissolves pretty easily. These shavings literally melted instantly when a little MAP torch was applied to them. A metal shaving would have held up better to heat.

[TexasJohn55]

Not all metals are magnetic, only 3 elements are naturally magnetic; iron, nickel and cobalt. Non magnetic metals include lead, aluminum, copper, magnesium, chrome and many others.

Engine bearings are overlayed with lead or lead alloy which is soft and will imbed tiny particles which helps protect the metal surfaces the bearing runs on. Typically the lead overlay is between .0005" and .002" thick, some may be thicker. Bearings typically are 2 or 3 metals bonded together in layers. Tri-metal bearings typically have steel base to hold shape layered with copper and then lead overlay. Some bearings use steel base with aluminum layered on top.

Lead deposits from combustion are not formed in strands or shavings, those can only be from peeling off an engine bearing surface. A magnet will not attract to lead or solder. Your magnet sticks to the cam bearing because of the steel backing.

[1970 skylark 350]

John, I should keep checking. I need to make sure what these shavings are from before putting the engine together.

The engine does not have a knock and the oil pressure seems good (no lifter noise), so it was a surprise to find any shavings in the pan.

Perhaps the shavings are from the initial layer you mention. I looked around the cam and cam bearing areas after removing the intake manifold. If I had a cam bearing problem, I should be able to find some shavings around the cam, shouldn't I?

I guess I could also remove some bearing caps and see what the bearings look like.

How hard is it to check the crank thrust end play with the engine in the car?

[TexasJohn55]

A cam bearing failure often progresses to the bearing drawing inward from the heat and eventually sticking to the camshaft. If you have a cam bearing failure, rotate the engine by hand and watch each cam bearing to see if it spins with the cam.

Crankshaft thrust is easily checked by inserting a large screwdriver between a main bearing cap and the crankshaft couterweight and prying, first one side and then the other, make note if travel seems to be over .010". A dial indicator is typically used with a magnetic base to position on the damper on front or on any flat surface of the counterweights on the crank. You can also use feeler quages betwen the crank and the thrust face. You can physically inspect the thrusts by dropping the main cap which supports them. If you plan on inspecting more lower main bearing shells, always leave at least one cap at each end torqued to support crankshaft in the seals, ie: 1 and 5 or 2 and 4, etc.

Note: you won't typically find metal in filter by pouring it out, you have to cut open filter appx 3/8-1/2" from base mounting end and inspect the bottoms of the pleats. Filters flow oil into pleats thru to the center return hole, flow is from outside in.Clean oil returns to engine thru center hole in filter.

[TexasJohn55]

When inspecting bearings, remember that main bearings wear the bottom shell and rod bearings wear the upper shell. Upper mains and lower rods typically show very little wear and will look almost new under normal conditions.