Anyone ever find plastic pieces in their oil pan?

[Whiplash]

Hi everyone. This is my first post on the forum. I just bought an one owner 71 Convertible, 4spd, AC, 350, SSG project car. The body is in great shape and it runs great.

I'm doing the required maintenance, new front suspension, steering, oilpan gaskets, rear main seal, radiator, etc.

When I pulled the oil pan I found a thimble full of hard plastic pieces, yellow/brown in color. They definitely have some kind of structure and are hard not pliable plastic. When I pulled the oil pump I found a ton of plastic in the pickup screen. Probably about a quarter cup of the pieces. There was nothing in the oil filter (I cut it open to check).

Anyone have any idea what this would be? If it was one piece when it went into the engine there is no way it could have made it through the oil passages from the heads down so I don't think it was dropped in from the valve covers.

The engine runs solid, starts right up, no knock, good oil pressure. I expect the oil pressure to be even better now that it has a clean oil pump and pick up installed.

I'm at a loss here. A friend of mine said it might have been some type of plastic plug(s) knocked out of the block at the factory when they put the motor together. I just don't have a clue.

I have pictures of the pieces but I don't know how to insert here on this forum.

Any ideas would be great.

Thanks,

Whiplash

 

[Tom B Hargrove]

Look to see if the plastic bushing that goes on the oil pump drive shaft is still there. That sounds like what it would look like. Other than that, not a clue.

Tom

 

[Whiplash]

Look to see if the plastic bushing that goes on the oil pump drive shaft is still there. That sounds like what it would look like. Other than that, not a clue.

Tom

Tom,

Thanks. The plastic is almost identicle to this shaft bushing (had to replace it when I pulled the pump). However, I have a Quarter Cup (big handful) of this stuff in there and it's hard corners with structural ridges in it (almost like how a pressed piece of plastic would look).

It's strange.

Hmmm

Thanks for the reply though.

Whiplash

 

[Tom B Hargrove]

That is strange. I completely rebuilt the engine in my 72 350, and didn't see anything that would leave that much plastic in the oil pan. It almost sounds like someone dropped something in it. I am going to watch your post to see if someone can identify it. Good luck.

Tom

 

[atmmac]

dammit i forget the name of the piece. It is a gear and is made up of some strange material that fails eventually in older GM cars. I just read about it the other day. Eventually the gear thing will break and your timing is screwed. The pieces are the gear probably starting to break up. Someone tell em the name i cant remember!

-Andy

 

[bill81vette]

I recall that some of my older chevys that I used to have ,the high mileage ones would need a timing chain and the parts houses would try to sell the (nylon?)gear instead of a steel gear because it was 'quieter'..perhaps this is what you are finding...good luck!

 

[patsnitrovette]

sounds like the upper(cam) timing chain gear to me

 

[4 webers]

Plastic pieces in the pan are quite common , both the pump shaft retainer and the cam gear are the culprits . The general decided years ago that plastic was the way to go on the cam gear .

Geo

 

[Florida Guy]

Sounds like the timing chain gear. They are made of nylon. Common part from the factory.

 

[72Mako]

On my '72 L48 at around 80K miles, I decided to replace the timing chain as PM. Boy was I glad I had a look see. The main body of the upper timing chain gear is made of alumnium with nylon/plastic gears cast onto the alum hub. A bunch of these nylon teeth were gone. I'm thinking I was a short while away from it jumping timing as hard as I was leaning on the ole L48. GM did this for quietness. I replaced it with a Cloyes all steel timing chain set and I didn't notice it being any louder. As others have said, probably the source of your plastic. Charles

 

[KenSny]

Replace the timing gear set and chain before you have SERIOUS engine repairs.

 

[Jack]

Whiplash:
As others said ... it's from the upper (Cam) gear of timing set ... where it shucked plastic sheath of teeth. I saw very same thing in my 71. Check to see what your timing set looks like ... maybe it's already been changed over to non-plastic ... if not, do so right away. You say it cranked & ran good ... so it's probably been changed over ... but you oughta take a close look.
JACK:gap

 

[Whiplash]

Whiplash:
As others said ... it's from the upper (Cam) gear of timing set ... where it shucked plastic sheath of teeth. I saw very same thing in my 71. Check to see what your timing set looks like ... maybe it's already been changed over to non-plastic ... if not, do so right away. You say it cranked & ran good ... so it's probably been changed over ... but you oughta take a close look.
JACK:gap

Thanks to everyone for the ideas here. Based on the descriptions it seams like this could be the culprit. It's a full handfull of plastic/nylon. I would have thought with this much plastic/nylon any gear it was from would be completely gone and the engine wouldn't run at all.

However, since the radiator, shroud, front suspension, and fan are already out what's a little investigation with the timing chain cover? This all started as a quick change out of the power steering cylinder over Thanksgiving and all I have been doing is that one more thing as long as I'm here game. If it goes on much longer I'm just going to pull the engine and lift the body and go for the whole 9 yards. Ha.

If anyone can tell me how to post a picture I'll post one of the debris.

Thanks again for everyone's help.

Regards,

Whiplash

 

[ChuckG]

Here's another thought....Just maybe sometime in the past, during an oil change, the gnurled part of the cap on the plastic oil bottle fell into the valve cover. Might have gotten ground up in there. Chuck

 

[Muleman]

Hello Whiplash,

Me Too!!! I bought a 71 coupe at Thanksgiving. I noticed a slight oil leak at the rear main and dropped the pan to fix. I found the same garbage in the pan and oil pickup screen. Way to much to be anything other than hamburger timing gears. The other plastics that could accidentally be there are much too soft. This junk is black, very hard and about a cup full. I had also noticed after getting on the throttle, my oil pressure would drop off way low. This was the pieces blocking the pump's pick up and starving the engine for oil. "Bubba the Great" had replaced the timing set without cleaning the lube system. Wonder if this was done out of ignorance or meaness? All of this failure and repair happened before I owned the car.
When this all started to make sense, I had to pull a piston to find out if the oil depravation had left its' mark. Oh yea, all the pistons had some galling even though the engine still ran strong with it's new timing set. AT that point, I bit the bullet and went through the engine with a complete overhaul of everything. $2500 later, I am back to where I thougt I was when I bought the car.
Moral of this story, If you ever have a plastic timing gear failure, you will have "pieces" everywhere that need to be removed. Save an engine, clean up the mess and do the job right. This junk won't dissolve and go away.
Good luck with your situation hopefully you found it in time.
Dave

 

[Willis76]

Which years and engines used this type of gear?

Just curious if anyone out there knows which ones or how to find out -

Thanks -

 

[Thumper]

These gears were pretty common in the 70's, as I've replaced a bunch of them with steel gears. My guess is that the timing gear failed and the previous owner had them replaced but never pulled the pan to clean out the broken pieces, which is why you're finding them today. You're lucky that they didn't get recirculated with the oil and cause more damage. But usually when they fail, you run the risk of bending a valve that happened to be open when it should have been closed and the piston hit it.

I'd still pull the timing cover to check on your timing gears....and while you're in there, you might as well change them. Double roller timing chain/gear sets are pretty reasonably priced these days.

:bang

 

[rgtrough]

Hey Whiplash and Muleman, welcome to the CAC. This forum has many knowledgeable and helpful members. Have fun with your sharks. peace Bud

 

[Whiplash]

Hello Whiplash,

Me Too!!! I bought a 71 coupe at Thanksgiving. I noticed a slight oil leak at the rear main and dropped the pan to fix. I found the same garbage in the pan and oil pickup screen. Way to much to be anything other than hamburger timing gears. The other plastics that could accidentally be there are much too soft. This junk is black, very hard and about a cup full. I had also noticed after getting on the throttle, my oil pressure would drop off way low. This was the pieces blocking the pump's pick up and starving the engine for oil. "Bubba the Great" had replaced the timing set without cleaning the lube system. Wonder if this was done out of ignorance or meaness? All of this failure and repair happened before I owned the car.
When this all started to make sense, I had to pull a piston to find out if the oil depravation had left its' mark. Oh yea, all the pistons had some galling even though the engine still ran strong with it's new timing set. AT that point, I bit the bullet and went through the engine with a complete overhaul of everything. $2500 later, I am back to where I thougt I was when I bought the car.
Moral of this story, If you ever have a plastic timing gear failure, you will have "pieces" everywhere that need to be removed. Save an engine, clean up the mess and do the job right. This junk won't dissolve and go away.
Good luck with your situation hopefully you found it in time.
Dave

Hey Muleman,

It's good to know someone else has this problem. My cylinder walls don't look scored so I'm hopefull the oil pickup and filter did a good job of keeping this problem down.

I've got an original numbers car 1 owner. The 350 is the 290 horse but I was thinking of stroking it to get some more push. I'm very concerned about having the rebuild done right while not grinding the numbers off the deck. Did you do the rebuild yourself for $2,500 or did you have someone do it for you? What did you get done for so little?

I'm trying to get the car back on the road for the Spring so we can enjoy it for a season (I've only driven it three times before I started ripping it apart). However, if I can get the motot done for $2,500 I might just pull it now and be done with it. Thanks in advance for the response.

Whiplash

 

[Muleman]

Hi whiplash,

I had a very reputable machinist in Jax Fl. -- Gary Johns, bore the motor an additional 30 thou., new rings, new Comp Cam 270, a comp valve job, new valve guides, new timing set, new roller rockers, all new bearings, all new gaskets and seals, and reassemble the engine. Anything that could have been hurt by running without enough oil was replaced. I am very pleased with his timeliness and product. The motor runs great.
I didn't see scoring on the pistons that were affected by the depravation of oil; I saw a galling or scuffing look on the cylinder walls and corresponding piston surface.
This was not caused by the particles grinding into the surface. It was caused by the particles blocking the oil circulation and depriving the surfaces of oil. Don't make the mistake of thinking all is fine if you don't see scoring. Look for heat damage on the moving and bearing surfaces. Good luck with your engine.

Dave