Topic: That should NOT be in my OIL PAN! Oh no...

[markreimer]

After ten days of straight shop time, I was on the last winter repair job - replacing the oil pan gasket. Pretty simple. I warmed the bike up, drained the oil, and pulled the pan. What I found inside made me feel sick. First thing I saw was a gooey mess clinging to the oil pump screen. It looked like a piece of gauze or something, probably a piece of a gasket?

Then I looked into the pan itself and saw a bunch of metal shavings. I'd seen this once before after I rode 3,500km to the coast, but after an oil change and the ride back home, the oil came out clean so I forgot about it. There was tons of metal bits in the pan. But upon closer inspection, I found what looks like two big chunks of a piston ring!!?

I've never opened an engine up before so I don't know what a piston ring looks like per-say, but this is pretty close to what I had imagined. But I can't understand how it would have made it all the way down into my pan! The PO said he replaced the rings shortly before I bought it. Perhaps it was a bad job and they blew apart as a result?

The concept of breaking the top of the engine open is very daunting to me. I have no experience with engine repair, but have faired well with the carb and brake system on the cb750, so I guess it's time to move on up. Give it to me straight - do I have to pull the engine and remove the top half to replace the rings? What is even involved in replacing rings??? I've read something about honing the cylinders (which I don't understand for the record), replacing the head and valve cover gasket, but that's about it. Is this something that a first timer could theoretically tackle? Any best practices, advice, other things to look for or replace while it's apart, etc? And any ballpark for how long it takes to do?

Should I be worried about other bits and pieces making it's way from the top half, through the bottom? Does this mean I should be cleaning out the lower half as well?

[markreimer]

And here is the sludge that was stuck to the oil screen, as well as a shot looking up into the engine.

[bryanj]

If your engine is running even and on 4 cylinders and not smoking, i suspect those bits got left in after a rebuild

[markreimer]

It is running yes. I started it up for the first time since winterizing it. It had a bit of white smoke for the first minute but then idled fine after for 5 minutes as I let it warm up the oil. I know the PO said he replaced the rings. Is there anyway to figure out if this is just a remnant? I've never pulled the pan before so I guess I don't know how long it's been there. I've only seen metal flakes in the filter housing, which hasn't been there the last two oil changes.

Would a compression test help identify damaged rings?

[Raul CB750K1]

If  it ain't broke- don't fix it. If it is the remains of a ring, the only way it could be from the running setup is if it is an oil control ring, otherwise it is impossible that a broken ring would get to the oil pan.

If the PO replaced the rings it may very well happen that was due to an engine breakdown, and he simply didn't bother recovering all the remaining bits. The hassle of removing bits from the crankcase bottom is not worth it many times. When  my CB350 broke the camchain I couldn't find half a link plate, it must be somewhere down in the crankcase but I didn't bother chasing it.

If I were you I would run the hell outta the bike, and worry about the rings when there are real symptoms that point to an engine rebuild. But that's just what I would do.

[faux fiddy]

Would a compression test help identify damaged rings?

Would be worth doing before tearing into it.

[dave500]

ill bet its part of the old ring dropped into the case by your careless po,as metioned if its not making any funny noises and running well just ride it.

[andrewk]

A compression test is where to start.

If you had a piston with a broken ring in your running engine, you would experience increased oil consumption, fouled plugs, smoking, etc.  If you've put 3500 km on this setup, that piece of ring is a left over from the engine rebuild.

At least you know he wasn't fooling when he said he replaced the rings.  :p

[trueblue]

Ok for the record, there is no way for a piece of a ring to break off and get into the sump without having a chunk of the piston in there keeping it company, it will stay in the ring groove and just go up and down with the piston, there isn't enough room for it to get past your piston skirt.  My best guess is it was left in there by a sloppy mechanic.

[Toxic]

Ok for the record, there is no way for a piece of a ring to break off and get into the sump without having a chunk of the piston in there keeping it company, it will stay in the ring groove and just go up and down with the piston, there isn't enough room for it to get past your piston skirt.  My best guess is it was left in there by a sloppy mechanic.

+1 stop worrying about it
Clean out your sump and screen and ride.

If it were part of your rings you would certainly know it.  Your bike would have allot more problems than you report.

I say you got lucky on this one.

[MoMo]

Ok for the record, there is no way for a piece of a ring to break off and get into the sump without having a chunk of the piston in there keeping it company, it will stay in the ring groove and just go up and down with the piston, there isn't enough room for it to get past your piston skirt.  My best guess is it was left in there by a sloppy mechanic.

TB is right on all accounts, the mechanic probably broke a ring while reassembling and could not fish the broken part out...Larry

[dhall57]

+1

If bike is running fine like you say it seems to be, clean the lower pan on pump screen and put it back together and ride it.  Like already has been said - If it ain't broke don't fix it !

Mark, both my KO and K6 have the common problem like most of these 40 year old bikes do and  that is minor oil seepage in headgasket area. But until it gets much, much worse Im not going to tackle engine removal to fix the problem. The paper towel trick works great and Im still riding both bikes.

[grcamna2]

It's nice that you removed the oil pan to clean out the sump in there...and get all that bad looking stuff flushed out and start w/ a fresh sump  ...clean as can be.I agree w/ trueblue & photolar. It'd be good to do a compression test(make sure the valves are adjusted first) w/ the engine fully warmed up w/ the throttle wide open and the choke wide open when you crank it up...just for you're records.I'd do that and record you're findings along with the present mileage...and just enjoy the fresh Spring season. 

[ADW]

If bike is running fine like you say it seems to be, clean the lower pan on pump screen and put it back together and ride it.  Like already has been said - If it ain't broke don't fix it !

I'd do a compression test just to have peace of mind, but agreed with everyone else that there's no way a ring could get into the sump without a tremendous catastrophic failure of the engine, or someone dropping it in there. So the PO dropped it in there. Take it out, button her back up, do a compression test, and then ride!

[markreimer]

WHOO! Guys, this is music to my ears, thanks so much for the advice!  I'll start with a good cleaning, do a compression test, and hopefully that's it!

[thrutheframe]

Mark,
  You found the metal bits and more impotantly what looks to me like a piece of a shop rag in your screen because you were doing your due diligence.  Carry on.

[bollingball]

At first look I thought it was the outside edge of an old screen filter.

                                                Ken

[754]

 First thing, check that piece with a magnet or see if its metal. Whe re ringing, and removing rings they could braek and fall down..its not like it will plug an oil hole anywhere..

[Bowswell]

Look like main bearing retainer behing sprocket .

[crazypj]

That's a piece of top ring, you can see chrome face.
 What does the outside of curve look like?
 It could be piece of the new ring?

[ekpent]

Measure what you have left maybe to give an idea as to its overall scale.Probably just a lost soldier living in there though.

[chickenman_26]

But upon closer inspection, I found what looks like two big chunks of a piston ring!!?

That's a piece of a brand new top compression ring, and I believe I know exactly how it got there. It's not uncommon for someone to snag a ring on the liner when trying to lower the cylinder block over the pistons. He doesn't notice, keeps lowering the block, the ring snaps, and the piece falls down into the bottom end. There's no way a snapped off piece of a top ring could get past the others and into the bottom end while the engine was running, unless a chunk of piston went along for the ride. If that were the case, you wouldn't be riding the bike.

Stu

[ekpent]

OOOH the plot thickens. Is it old or new ??

[bjatwood]

My guess is a old one. .....

[CycleRanger]

Look like main bearing retainer behind sprocket .

Didn't we have a thread just like this with the same conclusion recently?