Help engine failure diagnosis

[Voyager]

At 95K following a 5K trip my bike is showing me signs of serious engine trouble. So, during my month long wait for a service appointment, I thought I might ask for some help in diagnosis. Started it one morning to the (loud) sound of a ball peen hammer striking the crankcase. Seems to be timed with the left (as in riding) piston movement (increases with RPM). I popped the valve covers & checked the clearences & rotation, which all seemed to be normal (no extra sounds, not bent or poking into the piston head) No chips of metal in the oil, just a hint of tiny metalic flake when rubbed on the fingers. Can't see a hole in the piston through the spark hole. I'm thinking something failed from connecting rod to crank, bearing, wrist pin, etc. Opinions? Options?

 

Thanks.

[Rob L]

Check the timing chain adjuster on the left side. The hydraulic tensioner may be stuck.

[smiller]

Yes, probably the left-hand cam chain tensioner which is a known problem that seems to rear its head on some bikes. The noise is often confused with bearing or piston problems. Or at least let's hope that's the deal in your case as the repair is relatively cheap and easy.

[Voyager]

Yes, probably the left-hand cam chain tensioner which is a known problem that seems to rear its head on some bikes. The noise is often confused with bearing or piston problems. Or at least let's hope that's the deal in your case as the repair is relatively cheap and easy.

 

Check the timing chain adjuster on the left side. The hydraulic tensioner may be stuck.

 

Ah! I wouldn't have thought of that. Thanks guys, I hope you are right!

[Voyager]

Yes, probably the left-hand cam chain tensioner which is a known problem that seems to rear its head on some bikes. The noise is often confused with bearing or piston problems. Or at least let's hope that's the deal in your case as the repair is relatively cheap and easy.

 

Well, bad news..It doesn't look like it's the chain tensioner. I removed both & both seemed to function just fine in and of themselves. It didn't look like the parts were contacting anything but the chain. After re-assembly it makes the same sound. Thanks for the help though, it was worth a shot!

 

Any other ideas?

[smiller]

I removed both & both seemed to function just fine in and of themselves.

 

I'm not certain that mere freedom of movement (if that's what you're saying) necessarily confirms proper operation. The adjusters operate on engine oil pressure and if clearance is excessive they will leak down and provide insufficient pressure on the cam chain. I don't think you can verify proper operation with any kind of static check.

[Voyager]

Hmm. Good point. The manual is kind of,well, vague on the chain tensioners so unless there is a dynamic test I'm guessing replacement is the only way to know?

[smiller]

Hmm. Good point. The manual is kind of,well, vague on the chain tensioners so unless there is a dynamic test I'm guessing replacement is the only way to know?

Yes, probably so. Luckily replacement is neither expensive nor difficult. As mentioned this has been a known issue for some time and it affects some bikes more than others. I can barely hear the noise on the left side of the engine on my bike but on some oilheads the noise apparently progresses to sound quite threatening, and again is often confused with a more serious internal engine problem. BMW first released a fix in the form of a new tensioner assembly which was very effective but also a little pricey at around $200. This item has been discontinued (why? we are only the customer so we don't get to know) but new parts are now available that are much cheaper, like $40 will cover everything. Do the new parts address the same issue as the update parts? Again, we don't get to know. Pretty frustrating. Here is a thread from Advrider that explains the whole mess. It can be a little difficult to follow, but if you read to the end all will become clear, or at least you'll know as much as anyone can figure out so far since BMW is being typically mute.

[Voyager]

Thanks smiller! I ordered one today

[Voyager]

OK. So today I replaced the chain tensioner & have the same issue. Sounds like some failure in the connecting rod. If at idle under no load it quiets down some, but increase the RPM & it almost sounds as if the CR is being dislodged & impacting the piston/crank. Sooo...

 

I already have an appointment with a dealer, but since that is still THREE weeks away I have another question.

 

Can lower end engine work, specifically removing the pistons, connecting rods & bearings, be accomplished while the motor is in the bike or not. In other words, are there any necessary steps precluded by frame location? I've looked at the FSM which, of course, shows pictures of various special BMW part numbered alternate frame hangers & brakets that I don't have.

 

If the dealer verifies the issue AND my extended warrantee will cover repairs (or most of them) then I will let them do the work, otherwise, I am willing to try it myself before junking the bike.

 

Thanks for any help.

[Stan Walker]

can removing the pistons, connecting rods & bearings, be accomplished while the motor is in the bike or not.

 

Yes.

 

But not the crank or the main bearings, for that you need to split the engine case.

 

Stan

[Voyager]

Thanks Stan.

[dcm3]

I had a similar experience, although at much lower mileage. The engine suddenly sounded as though there was major piston slap. The BMW tech thought it was valve adjust or chain tensioner, but those fixes did nothing. After doing a little search on the subject, I suggested that it might be rocker arm end play. He doubted it, but since had no other ideas, he checked it and adjusted it. Presto, problem fixed. You might check it out.

[Voyager]

Thanks Dale. It's worth a look while I wait for the BMW appointment.

[smiller]

Sorry to hear that the cam chain tensioner replacement didn't help. Do try checking the end play and anything else you can think of. I don't think I can remember ever hearing of a serious bottom-end problem on an oilhead engine and hopefully this won't be the first. Please let us know what you find out...

[Stan Walker]

I don't think I can remember ever hearing of a serious bottom-end problem on an oilhead engine

 

I know of one on a '94 RS. One of the cam chain guides shattered at 159,000 miles while she was riding it. Pieces of the guide were sucked into the oil pump pickup and blocked the oil flow starving the main / rod bearings with the normal result, a totally trashed engine. For many years I've been wondering if that would be the normal fate of a high mileage oilhead engine. For the record her husband (a very good wrench) rebuilt the engine and she rode it for many more smiles...

 

And one report recently where the dealer blamed rough running / low compression on a bad lower end. I don't have any faith in this report.

 

I've heard of a few engines that were bad from the factory.

 

And that's about it. A few failures out of thousands of engines and millions of miles.

 

I wish the final drives and trannies were as reliable, it would make a great bike into something truly special.

 

I would cut upen the oil filter and see if it has been collecting anything of interest before I did anything as drastic as yanking the rods.

 

Of course if it's all free, let the dealer worry about it.

 

Stan

[Voyager]

I would cut upen the oil filter and see if it has been collecting anything of interest before I did anything as drastic as yanking the rods.

 

I didn't think of that. I drained the oil and found nothing offensive in the mix, but I suppose if the filter is doing it's job, there wouldn't be. No chunks anyway.

 

I looked up the endplay adjustment in the FSM (or reasonable faximile that I have). As usual it was vauge & not so helpfull. It has one picture for the placement of the feeler guages (with tolerances) in setting endplay after re-assembly but no indication of adjustment point or where the "min" & "max" values should be. Any help there? I ordered a Haynes & it should arrive this week. I'll have a look at it then.

 

Thanks for all the help. I hope I'm not pioneering a lower end failure trend. It would be nice if an adjustment could bring her back to life. The wonderful Rhode Island summer is passing me by quickly

[dcm3]

Here's a link OREPAD that describes everything you'd like to know about rocker arm end adjustment. Remember, all the usual disclaimers apply!

Good luck.

[Voyager]

Wow. A what a technically superb and philosophically insightful reference! Thanks! This should be plenty of rope for my self inflicted hanging!

[jacko]

A mate of mine is going throught the same sort of thing with his 1150rt.

Motor makes loud knocking sound mostly when hot.Also has low oil pressure.

Its a long story really.But the guts of it is that it was stripped,crank ground bearings replaced ect.

Nothing was really found that they could say was definately was the cause.

Anyway we went on a round oz ride 15k all up, (one big Italian tune up really).

About half way into trip its knocking its guts out again.

Get home sure e-nuf low oil pressure ,back to shop new oilpumps this time,knock knock low oil pressure still.

So its back in shop for 3rd time for another look, got us and all the experts stuffed.

Maybe be you could check the oil pressure,you at least have warranty on your side the mate didnt for the first time but 2nd go was and the 3rd will be.

best of luck regards Jacko

[Voyager]

Hmmm. Good thought. Is there an in-line or factory mount take-off pressure guage of prefference? I've only rigged the cheap auto versions for manual pressure. Hope you find an end to the bike trouble. Thanks.

 

Sid

[Stan Walker]

got us and all the experts stuffed.

 

Any cosideration given to the oil pressure relief valve?

 

I've never taken one apart so I can't guess if it's possible for it to stick. But, if it can and it sticks in the open position you get low pressure. If it only sticks occasionally you could get a pressure problem that comes and goes. It might even be temperature sensitive.

 

Just a thought. You've just about swapped out everything else.

 

Stan

[jacko]

Relief valve was the first thing we tried after checking the oil pressure on my bike.

Both bikes are 02 r1150rtp, purchased at the same auction

The oil pressure on mine was right on spec no probs.

The other bikes oil pressure did jump all over the place,

So we went straight to the relief valve.

regards Jacko

But it couldnt be that easy.

We changed oil,cut filters open,found nothing.

Thought on the round oz thrash we might of found the problem

laying on the road,but that didnt happen either.

My diff spewed itself onto the road, buts thats another story.

regards Jacko

[Slartidbartfast]

I would never bother to tear down the bottom end of an oilhead engine, chasing ANY problem. A used, replacement engine would be a far surer fix and probably cheaper.

[jrbldr]

If you still have the oil you drained, a quick analysis by a competent facility will probably identify the problem. They can tell from the metals in the oil which bearings have failed. By your description, it sounds like a rod bearing to me but just a guess. Main bearing would be more likely to show up when warm, combined with low oil pressure, and a deeper knock. Good luck.

[2wheelterry]

If you still have the oil you drained, a quick analysis by a competent facility will probably identify the problem. They can tell from the metals in the oil which bearings have failed.

 

Althought they can sometimes generalize, i.e. its a bearing failure. In my experience, the oil analysis labs cannot conclusively ID the source of the contaminent only the type of metals, etc. found.

 

Its still a good recommendation and its not too expensive.

[smiller]

I would never bother to tear down the bottom end of an oilhead engine, chasing ANY problem. A used, replacement engine would be a far surer fix and probably cheaper.

That's a good point... a low-miles take-out engine would probably cost less than the parts alone for any repairs, be a much simpler job, and probably be more reliable as well.

[Art..]

http://www.beemerboneyard.com/coen1.html

[Voyager]

Update: Called the shop today. They said they tinkered with the chain tensioners, put it back together & it doesn't make the noise any more.

 

Well, I'm not complaining, but it seems strange. I pulled both of them out, replaced the left one with new parts & nothing changed for me. I'll be glad to get it back. That $3.20 per gallon will go a lot farther on the bike than it does in my truck!

 

Thanks for all the help. 95K and still going!