V11 Sport with strange metallic rattle

[Tinus89]

If a seat comes loose it will drop quickly, it will then jam between the valve and the head, the piston will then hit the valve and shatter it leading to carnage that has to be seen to be believed.

 

I've seen it.

 

Having just trawled through this thread's last six or so pages all I can suggest is a last nut and bolt strip and inspect and a full 'Zero Time' on the engine. So much has been done to it piecemeal there is no way it can be known to be right unless it is ALL done right.

 

When the crank was out were the rods closed and ground or just bunged back in with new shells? If they weren't then there is one huge glaring failure right there. And what about the little ends? Anybody check them for out of round or ovalisation? Has the oil pump been removed and inspected/measured? Mention has been made of the cam chain being reluctant to disengage from the cam sprocket but nobody suggested replacing it!

 

Look, I'm not being critical, everyone is trying to help, but with typical Red Suspender frugality the attempts to *Save Money and Effort* have simply resulted in an twelve page ongoing testament to failure.

 

Start again. Buy some good measuring tools and DO IT RIGHT,

 

Pete

 

Thanks for doing so! So clearly, I should not expect it to be a loose seat.

 

When the crank was out, I brought it to an experienced engine shop, who measured and repolished the bigends on the crankshaft. The rods were measured for roundness and fitted with new shells, but not reground. The little ends were only visually inspected I guess, I dropped the whole assembly off there. I followed the shop's advise there and did not try to save money. E.G. they suggested I could re-use the conrod bolts once, but I decided not to do so.

One main bearing was replaced, the other was OK.

 

Oil pump was removed and inspected, bearing replaced. Because the oil pressure was measured with half-warm engine at 4.5bar at just off idle, I did not see reason to further investigate the pump.

 

Cam chain and sprockets were all replaced!

 

Look, I really value everyone's expertise, but I disagree I am trying to fix it half-way by not doing certain stuff resulting in a 12-page topic. The only alternative is either driving her till something fails, or dropping her off at a shop and let them find it for me, but because it requires an investigation, the counter will start at 2000 euros in labor easily.

[Chuck]

A few pages back, you said the noise was in the top end. You can pull the heads, have a look, etc. and put them back together in an afternoon.

[Scud]

Tinus - it sure seems you're in a tough spot. On one hand, you want to trust the work of the mechanics. On the other... anyone can make a mistake (like failing to torque a bolt on a connecting rod) and it seems that only disassembly and inspection will reveal the problem. 

 

Then there's the ride-it-till-it-fails approach. And if the failure is catastrophic, you either find out what was wrong and fix it - or you're left with a pile of parts that's not worth fixing.

 

I had a similar noise on my Champagne LeMans project - right when I thought I was "done."  I can't tell you what to do, but here's what I did:  I pushed it the corner and focused on other stuff for a while (then I scavenged a few parts to get my Greenie project on the road).  I think I'm gonna pull the engine and strip it down as Pete described above.  It's either that or part it out, which seems a shame.  I wouldn't enjoy riding it if I was worried about reliability.

[Scud]

Looks like Chuck and I posted at same time. You could certainly start with the heads as he suggested. If you find nothing wrong, you can keep going from that point.

[Tinus89]

All,

 

 

Again thanks a lot for the help, really appreciated!

I am trying to find the time to pull the heads and inspect them! Anything in particular I should focus on? Valve stem/guide wear?

 

There are two things I just want to make perfectly clear, as it seems there is some misconception...

 

- The sound did NOT start after any work on the engine! It first started to appear with a hot engine, and increasing in loudness and earlyness after a cold start (now

- I did the full re-assembly myself, not a mechanic focusing on 5 projects at the same time

[Chuck]

 

 

 Anything in particular I should focus on?

Ok, I'd first look at the rocker arms sliding back and forth on the shafts. 

 

 

Valve stem/guide wear?

I would be surprised if that would make a noise you could hear.   Naturally, I'd check valve clearances. The *first* thing I do when trouble shooting is a leak down test. Of course, that just gives you a general impression of the condition of the engine. It won't find a noise unless there is a pretty obvious failure.

Valve clearance ok? Rocker arms not rattling back and forth? Time to go deeper..

[pete roper]

Just revisiting this again and getting back to first principles. Are you sure that the throttle body balance is spot on? If it isn't there will be knocking from the gearbox and, if it's got a single plate clutch, from the springs in the friction plate. I seem to recall you saying it has a twin plate clutch which should be silent with the lever released but sing a bit with the lever pulled. The single plater behaves in the opposite way. Out of balance TB's though will accentuate the accelerative and decelerative actions on the input shaft to the box and the knocking of the primaries. Also if your idle speed is too low it will be a lot worse.

 

Pete

[Tinus89]

Hey all,
 
 
After sucking so much of your knowledge here, it is time for me to bring some back to the community .
Or in other words: Ladies and gentlemen, we've got him!  .
 
Now in technical terms: I found the rattle. Good and bad though. This is how:
 
- Ran the engine without rocker covers, no issues found. In re-checking the valve clearance with the plugs installed, I sensed a difference in compression between left and right.
- Did a compression test: Left 9 bar compression, right only 7.5bar. Strange. Poored some oil on the piston and re-tested: straight to 9bar. So it's the rings leaking, not the valves.
 
Does that matter? A difference in compression? She runs fine, really. Then a bloke who was visiting said: so you have blow-by, does it not build up crankcase pressure?
In my explaining of the nice Guzzi crankcase vent system, I passed by the check valve in the vent line. Then we both looked at each other and went: nooooo......
Took out the check valve, ran the engine: silence. The rattle was the little ball jumping up and down on the crankcase pressure.
 
 
So, some questions: 7.5bar compression, is that real bad? What would cause the rings on only one piston to slowly go? (As it initially only occurred on a real hot engine, slowly increasing over time).
Does it hurt to run the engine without the check valve in the vent line?
Would you already take her apart again and machine the cylinders, buy new rings and possibly even new pistons? Or wait until oil consumption becomes an issue?

[docc]

I don't recall anyone actually finding the check valve ball on a V11. Mine does not have one. Others have reported the same.

[Scud]

Good news.  And where is that rattling check-valve, exactly? I'd like to try that test on my noisy champagne LeMans.

 

Bad news.  A leak-down test will tell you more about the condition of the rings than a compression test. You need an air compressor and leak-down tester - or you could have a shop do this simple test. With a leakdown test, you can hear exactly where the compressed air is escaping and know for sure if it is rings, intake valve, or exhaust valves.

 

And if it runs fine... ride it. Wrench when winter comes.

[bbolesaz]

Mine has no check valve.

 

However, there are bikes that do.  BMW Airheads use a disk flapper valve at the top of the motor just under the breather hose connection.  The theory is that if it is always expelling air, the crankcase pressure is reduced which reduces windage losses.

 

I'm assuming the check valve is on the breather outlet hose, the one from the big bolt on the spine top back to the airbox.

[docc]

Pretty sure it’s at the bottom of the rubber hose at the actual vent outlets.

[Lucky Phil]

Hey all,

 

 

After sucking so much of your knowledge here, it is time for me to bring some back to the community .

Or in other words: Ladies and gentlemen, we've got him!  .

 

Now in technical terms: I found the rattle. Good and bad though. This is how:

 

- Ran the engine without rocker covers, no issues found. In re-checking the valve clearance with the plugs installed, I sensed a difference in compression between left and right.

- Did a compression test: Left 9 bar compression, right only 7.5bar. Strange. Poored some oil on the piston and re-tested: straight to 9bar. So it's the rings leaking, not the valves.

 

Does that matter? A difference in compression? She runs fine, really. Then a bloke who was visiting said: so you have blow-by, does it not build up crankcase pressure?

In my explaining of the nice Guzzi crankcase vent system, I passed by the check valve in the vent line. Then we both looked at each other and went: nooooo......

Took out the check valve, ran the engine: silence. The rattle was the little ball jumping up and down on the crankcase pressure.

 

 

So, some questions: 7.5bar compression, is that real bad? What would cause the rings on only one piston to slowly go? (As it initially only occurred on a real hot engine, slowly increasing over time).

Does it hurt to run the engine without the check valve in the vent line?

Would you already take her apart again and machine the cylinders, buy new rings and possibly even new pistons? Or wait until oil consumption becomes an issue?

Did you have the throttle wide open during the comp test? Was the engine at operating temp? 108psi is very low and 130 isnt exactly up there either. Of equal importance is also how the engine makes its final compression numbers. A good engine should give you the maximum reading in 2 or maybe 3 steps, if it creeps up there in 4 or more steps thats not great.

Pleased you found the rattling ball cause....great info that.

 

Ciao  

[Chuck]

As I mentioned a while back, it's time for a leak down test. .

[docc]

As I mentioned a while back, it's time for a leak down test. .

I'd like to see a "How To . . . " thread on that procedure . . .