Author Topic: Not really a new topic. Cam failures 8V.  (Read 67964 times)

Vasco DG

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Not really a new topic. Cam failures 8V.
« on: November 17, 2014, 03:54:21 AM »
Interestingly I'm finally beginning to see cam failures coming through in my shop. Things that are worth noting.

1.) The failures are all occurring in spring after a wet winter.

2.) They usually manifest themselves immediately after a service. I have no certain idea why. The only thing I can think of is that the high carbon content of the dirty oil may contribute some form of added protection and once new, clean oil is in circulation it all goes pear shaped very quickly.

3.) Engines seem to start misbehaving long before there is visible damage to the tappets but at the same time similar wear patterns on functioning cams do not seem to necessarily be terminal. For example I inspect my cams and tappets about every six to nine months and while they have a similar 'Pattern' on their nose circles, (Which is where the cam failures begin oddly, rather than the opening flank as I'd expect.) but my great lump of Munt soldiers on seemingly impregnably!?!

4.) Long before the valves become really noisy signs of the demise of the cams and tappets will begin to manifest themselves by firstly misfiring and hesitation as the throttle is opened with no load at about 2,000-2,500 rpm, this is easy to overlook if you don't know what you're listening for. Secondly the engine will start spitting back through the throttle bodies, this can be both seen and heard, at idle. A drop of engine speed and a 'Chuff' accompanied by the physical rearward movement of the TB's between the boot to the manifold and trumpet to airbox.

To paraphrase our ridiculous governments propaganda about chanting fanatics be alert but not alarmed. Keep your oil hot and ride 'em hard. They'll be far less likely to fail if you thrash 'em!

Pete

Offline Tazturtle

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Re: Not really a new topic. Cam failures 8V.
« Reply #1 on: November 17, 2014, 04:37:03 AM »
Thanks Pete.

I'm doing my best to flog her. It's easy to do!

Kurt

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Offline pauldaytona

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Re: Not really a new topic. Cam failures 8V.
« Reply #2 on: November 17, 2014, 05:02:52 AM »
Well it starts before you hear it, in the picture look at the dlc that is not even anymore, and that gave the heating on the cam lobe. That makes the cam rough, and that then takes the rest of the tappet away. It can take 2mm of the tappet. But anyway the engine runs and brings you home.


« Last Edit: November 17, 2014, 05:09:32 AM by pauldaytona »
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Re: Not really a new topic. Cam failures 8V.
« Reply #3 on: November 17, 2014, 06:24:11 AM »
 Pete,what brand oil are you putting in those bikes? Average miles on the bikes? Brand specific cam failures in cars after thousands of miles are mostly bad heat treating on cam and or what makes contact with the cam . Oil with low ZDDP can be a factor but years ago when some OHV and OHC auto engines had epidemic failures it was bad materials..

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Re: Not really a new topic. Cam failures 8V.
« Reply #3 on: November 17, 2014, 06:24:11 AM »

Offline youcanrunnaked

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Re: Not really a new topic. Cam failures 8V.
« Reply #4 on: November 17, 2014, 06:58:24 AM »
So many questions!

How many of these have you seen?

Can any of the failures be attributed to poor break-in,  lack of proper maintenance, or abuse?  Or is it happening despite the owner doing everything "by the book?"

Is there any pattern as far as model, year, or date of manufacture?

Are these engines still under warranty?   

For bikes either within or outside of the warranty period, what has been the factory's response as far as parts, repairs, and financial responsibility?

What does fixing this entail, and what is the cost?  Are the failed engines getting upgraded to roller tappets?

Have any of the failures occurred among the engines with roller tappets?  If not, from the damage that you have inspected, do you anticipate that the roller engines will not have these failures?





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Offline leafman60

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Re: Not really a new topic. Cam failures 8V.
« Reply #5 on: November 17, 2014, 07:05:29 AM »
 Oil with low ZDDP can be a factor but years ago when some OHV and OHC auto engines had epidemic failures it was bad materials..

Ditto on both points.

A little inexpensive insurance-

http://barsproducts.com/catalog/view/245-3x-concentrated-engine-oil-supplement-with-zinc-treatment-4405

http://zddplus.com/


Considering the past issue with materials hardness (and the recall) that afflicted early Stelvio models, I'm wondering if a smattering of that same issue from the same suppliers may be a persisting issue.

The overall incidence of failures may be small, though.  I dunno.


.
« Last Edit: November 17, 2014, 07:18:36 AM by leafman60 »

Offline pauldaytona

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Re: Not really a new topic. Cam failures 8V.
« Reply #6 on: November 17, 2014, 07:34:12 AM »
we had all abuse and oil discussions in the past, not doing it over again. In German Stelvio forum we made a list of members with the problem. 30 until now.

http://www.razyboard.com/system/morethread-liste-aller-betroffenen-mit-nockenwellenschaden-stelvioforum-1988046-6198716-310.html
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Offline brlawson

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Re: Not really a new topic. Cam failures 8V.
« Reply #7 on: November 17, 2014, 08:37:06 AM »
I just surpassed the 50,000 mile mark on my Stelvio and have noticed a few symptoms.

The backfire through the throttle bodies happens but only on startup after a spirited ride.

Valve lash has been an issue this summer with frequent adjustment. Exhaust valves on left bank in particular loosing up. I even had a couple of valve tighten up a bit on this last check. Never had any real issue in this regard for at least the first 30,000. I did notice a faint but unusual noise in the engine and GuzziSteve replaced the two exhaust lifters on the left side due to unusual wear patterns. The cam looked ok at that time. Everything seems ok except that it always seems to come back to the same suspects.

Fortunately, the engine has always run as it should and I do ride it as Pete recommends but I may well do the roller tappet upgrade before the worse happens.
« Last Edit: November 17, 2014, 09:13:07 AM by brlawson »
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Vasco DG

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Re: Not really a new topic. Cam failures 8V.
« Reply #8 on: November 17, 2014, 08:55:05 AM »
As Paul says this has been discussed ad-nauseam there is no need to cover the same ground again. I am certain I know the cause and the recent nature of the failures I'm seeing is relevant hence my mentioning it as a new data point. I'm only now, seven years into the life of the engine, beginning to see failures in my shop.

With the bikes I'm seeing I'm catching the damage early and so far on these bikes there is, at least to me with my bad hearing, no audible signature to the failure, it's the poor running that has alerted me and a check of the valve lash has confirmed it. Once the hard coating has gone from the tappets though they wear quickly and THEN they get real noisy, real quick.

Pete

Offline kevdog3019

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Re: Not really a new topic. Cam failures 8V.
« Reply #9 on: November 17, 2014, 09:49:47 AM »
Sounds faintly similar to Lario issues, though the cause is not necessarily similar. I DLC coated my cam/tappets in hopes of better wear. Is this something anyone considers Pete?  Makes perfect sense, but pricey yeah.
Kevin
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Offline JoeW

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Re:
« Reply #10 on: November 17, 2014, 10:27:50 AM »
In the 80s Mercedes had a rash of cam failures. It seemed to be across the board, 6&8 cylinder gas motors as well as 4&5 cylinder diesels. All over head cam engines. The theory was, the oil would be forced out from between the cam and follower while stationary. On start up, the hardness would gradually be scraped away. Once the hardness was gone, the cam would wear quickly.
Joe Walano

Vasco DG

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Re: Not really a new topic. Cam failures 8V.
« Reply #11 on: November 17, 2014, 11:05:57 AM »
Sounds faintly similar to Lario issues, though the cause is not necessarily similar. I DLC coated my cam/tappets in hopes of better wear. Is this something anyone considers Pete?  Makes perfect sense, but pricey yeah.
Kevin

Stock tappets are DLC.

Offline BlizzGuzz

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Re: Not really a new topic. Cam failures 8V.
« Reply #12 on: November 17, 2014, 12:42:14 PM »
First 8V cam failure in Norway?

Never heard of one until it happened to me a month ago...
Started it up to take it to the shop for winterizing in October, two days after oil and filter change at 48K kilometers on the meter, and heard a more pronounced valve ticking sound.
Last oil change before this was in the authorized Guzzi repair shop at 41K. The bike has been serviced by skilled mechanich at an authorized Guzzi garage every 10K kilometers since new.
And I have changed motor oil and filter between the ordinary service intervall. 
About the valve sound: Didn't give it much thought other than I thought it probably had to do with cold start in chilly weather.
Didn't notice anything unusual on my way to the garage. Didn't notice anything unusual on my daily Stelvio trips the days before either. 

A few days later the mechanic contacted me and told me that the valve clearance was more out of specs than it had been before.
A closes inspection revealed this (very visible cam lobe wear and "curved" wear on the tappets) :





The bike is a 2012 modell 8V, registered on me as the first owner in september 2012, engine no. AC012543, build March 14th according to the mechanic at the local Guzzi garage.
He contacted the importer promptly after the miserable discovery and confirmed the day after that the whole package will be covered by the warranty – new parts and the repair:

I have to admit that I've become a bit skeptic to the Moto Guzzi quality after this. I seriously think that such wear shouldn't be happening on a well-built bike like this after just 48 K kilometers.
Fortunately things seems to turn out good for me and I hope that the flat tappet design will be replaced with roller tappets and make my Stelvio fit for fight again when Spring is here in a few months:


Offline kevdog3019

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Re: Not really a new topic. Cam failures 8V.
« Reply #13 on: November 17, 2014, 01:06:45 PM »
Stock tappets are DLC.
Doesn't make sense that one is and one isn't. You're only as good as your weakest link. Of course it's only now that we're finding out the weak link or contributing theories on cause.
Kevin
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Vasco DG

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Re: Not really a new topic. Cam failures 8V.
« Reply #14 on: November 17, 2014, 02:28:59 PM »
It should also be remembered that there have been two or maybe three updates to the flat tappets. The original A5 motors used chilled cast iron tappets which there was a recall on. All of these should of been replaced by the forged steel with DLC type used in the A8 and on motors. At some later point, I think around 2012 sometime from memory the part number for the forged tappets changed but they still appear identical to the earlier ones so it might just of been due to a change of supplier.

Some, especially in cool, damp climates fail very quickly. Some, like mine, seem to soldier on forever. Certainly understanding the 8V and servicing it correctly makes a big difference. Using mineral oil in it is a recipe for disaster but is alas very common. I remain skeptical about the whole ZDDP issue but ensuring the oil has a higher level certainly can't do any harm. Understanding the extremes of heat and cooling seems to be most important factor in longevity and prevention in my experience.

Pete

Offline Gliderjohn

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Re: Not really a new topic. Cam failures 8V.
« Reply #15 on: November 17, 2014, 02:35:50 PM »
Pete,
You mentioned in a recent thread that in cold weather one should restrict the air flow to the oil cooler on an 8V. How do you determine how much to restrict without either over or under doing it?
GliderJohn
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Vasco DG

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Re: Not really a new topic. Cam failures 8V.
« Reply #16 on: November 17, 2014, 02:44:11 PM »
Do a search for the 'Simply Brilliant' thread.

I use an oil temperature dipstick to ascertain oil temperaure. Having an adjustable baffle gives flexibility. Anyone with half a brain will soon be able to look at the ambient temperature on the dash and quickly work out how much baffling is needed to keep the oil temperature up with a bit of experience. The temp guage can then be used to confirm it.

Pete

Offline Gliderjohn

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Re: Not really a new topic. Cam failures 8V.
« Reply #17 on: November 17, 2014, 02:55:38 PM »
Thanks Pete.
GliderJohn
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Offline pyoungbl

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Re: Not really a new topic. Cam failures 8V.
« Reply #18 on: November 17, 2014, 04:04:31 PM »
I recently rode to Swamp Scooters in Louisiana...a 2500 mile round trip.  On most days I was riding in the 50s to 60s but there were a couple mornings where I started out in the low 40s.  I found that I could always rest my bare hand on the valve cover, even at 75mph on the Interstate .  That tells me that the oil was only getting up to about 150F at most.  On part of the return trip I put two strips of Duct tape across the bottom of the oil cooler.  That did not change anything.  Next I'll add another two layers and check with an IR thermometer.  The NTX has such a huge oil radiator it's going to take significant blockage to get the oil up to 220-250F, where I would like to see it.  My gas mileage was only 36 mpg and I attribute that to over cooling.

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Re: Not really a new topic. Cam failures 8V.
« Reply #19 on: November 17, 2014, 04:41:49 PM »
Pretty quickly after taking ownership of my Stelvio I put on this cover.  At the time I wondered if I was restricting the cooling too much. I'm not concerned after reading this thread. Above 85F I can feel the heat coming off the cylinders on my legs. I've ridden in 95F-102F for hours at 80mph+ on the Stelvio (2012) with no issues.

I'd much rather ask for forgiveness than ask for permission.

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Offline jacksonracingcomau

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Re: Not really a new topic. Cam failures 8V.
« Reply #20 on: November 17, 2014, 07:19:11 PM »
Interestingly I'm finally beginning to see cam failures coming through in my shop. Things that are worth noting.


4.) Long before the valves become really noisy signs of the demise of the cams and tappets will begin to manifest themselves by firstly misfiring and hesitation as the throttle is opened with no load at about 2,000-2,500 rpm, this is easy to overlook if you don't know what you're listening for. Secondly the engine will start spitting back through the throttle bodies, this can be both seen and heard, at idle. A drop of engine speed and a 'Chuff' accompanied by the physical rearward movement of the TB's between the boot to the manifold and trumpet to airbox.


Pete

I know you've dismissed this before but #4 is classic inlet valve recession, if you ever get one at this stage (spitting back) check clearances then, my bet is tight not loose. Then at zero clearance it goes pear shaped VFQ.
Trying to help, not criticise . Are the ones you're seeing now all four lobes ?
Are you seeing any tight clearances ever ?
Pic of valve head after tits up cam should show story too
MH

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Re: Not really a new topic. Cam failures 8V.
« Reply #21 on: November 17, 2014, 07:26:49 PM »
Clearances aren't the issue, believe me.

Pete

Offline leafman60

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Re: Not really a new topic. Cam failures 8V.
« Reply #22 on: November 17, 2014, 07:30:29 PM »
If oil operating temperature is a concern, a thermostat can be added to any oil cooler not so equipped.

http://wildguzzi.com/forum/index.php?topic=73346.msg1143225#msg1143225



Vasco DG

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Re: Not really a new topic. Cam failures 8V.
« Reply #23 on: November 17, 2014, 08:23:51 PM »
The issue with that is that it is weighty, complex and adds a whole heap of leak points. It also wouldn't be cheap and would be an eyesore. If you don't mind those things then yes, it's an alternative. My own favourite is Mark Salkeld's sollution which is cheap, simple and will work just as well but required a bit of owner input.

Pete

Offline leafman60

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Re: Not really a new topic. Cam failures 8V.
« Reply #24 on: November 17, 2014, 08:39:53 PM »
Those thermostats are not very large and can be nestled in to the cooler circuit pretty discreetly.  I have one that is barely 2 inches square and plan to install on my Stelvio.  I'll post pics later.
« Last Edit: November 18, 2014, 06:33:59 AM by leafman60 »

Offline leafman60

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Re: Not really a new topic. Cam failures 8V.
« Reply #25 on: November 17, 2014, 08:56:49 PM »
Ya know, the more I read here about this topic, the more I wonder if this is not a quality control issue with metals, hardness etc as has occurred in the past.

Many thousands of cam-in-head BMW 1100, 1150 and 1200 boxer engines built from 1994 to 2010 had a "flat tappet" type valve lifter design. BMW has experienced issues in other areas but I have not yet heard about serious premature wear issues related to these flat lifters.

Part #5, BMW parts fiche


Even the 2010-2013 and the new 2013-2014 water cooled engines with overhead cams do not use any roller device but utilize a flat "drag lever" that rides on the camshaft.
« Last Edit: November 17, 2014, 09:24:54 PM by leafman60 »

Offline jacksonracingcomau

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Re: Not really a new topic. Cam failures 8V.
« Reply #26 on: November 17, 2014, 09:22:01 PM »
Clearances aren't the issue, believe me.

Pete

What makes them spit back, falter at idle etc ? As you say this is the big clue, loose clearance won't envoke this, somehow there is spark happening in manifold, on old engines this can only be ignition timing or valve leak, on modern MX bikes it is always valve problem, search CRF Honda valves, million theories why, but changing not adjusting the only way, once they've started they keep recessing.

After service is another clue, if valves were tight, then clearance reset, sounds like deja vu all over again, I met this issue a long time ago.

Hope I'm wrong but it's so very familiar.
MH

Vasco DG

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Re: Not really a new topic. Cam failures 8V.
« Reply #27 on: November 17, 2014, 11:57:32 PM »
Well it will if you understand the fueling parameters. Martin, I'm sure you have extensive experience in failures of this type on other, probably carbureted, machines. The symptoms will be markedly different on a machine that fuels mainly from sensor input rather than atmospheric pressure. And yes, I do know there is an air pressure sensor.

Pete

Offline lucky phil

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Re: Not really a new topic. Cam failures 8V.
« Reply #28 on: November 18, 2014, 12:27:33 AM »
I did some research on DLC as I was considering it for the Daytona engine I'm rebuilding. Apparently it's ok on tool steel lifters but nothing else and I think its an issue if you float a valve. fails badly if that happens from memory due to the impact.
With what Pete outlined and others feedback on the pre cursers to  lifter issues, would instead of valve seat recession being the cause of running issues it may be an intermittently sticking valve?
That would give the same symptoms as the riding valve and also pound the lifters badly whan the clearances opened up which may cause lifter failures.
Would also be more likely with machines that are little used in a cold climate.
Just something to consider from left field.
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Offline youcanrunnaked

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Re: Not really a new topic. Cam failures 8V.
« Reply #29 on: November 18, 2014, 06:35:47 AM »
I don't understand why I am getting "we have discussed this before" in response to my specific questions about these specific incidents that you have been experiencing of late, Pete, but I have been following this issue with great interest, and I believe these are important questions that have not been previously answered.  (How could they?  They pertain to incidents that you first disclosed in this thread one day ago.)  Of course, it is your prerogative to ignore them, but I really wish you wouldn't.
« Last Edit: November 18, 2014, 06:39:08 AM by youcanrunnaked »
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