Not really a new topic. Cam failures 8V.

[leafman60]

Pete, you have stated your theory that this problem is caused primarily in cold, wet climates and results from moisture condensing on the inside of the valve covers and finding its way down to the lifter mechanism causing microscopic rust that results in premature wear.

If this is true, how about lining the inside of the valve cover with an insulating barrier of gasket cork or maybe felt to inhibit such condensation. I'm not totally buying into this theory but, if it is correct, an insulation barrier on the inside of the cover or even just positioned across the valve mechanism without contact should help.

About 30 years ago, on a cold winter morning, I had ridden my Shovelhead a short distance afterwhich I decided to check the primary chain tension.  When I removed the slick chrome derby cover to expose the inside of the primary chaincase, the inside of the derby cover was coated with moisture-emulsified oil that looked like mayonnaise.

Moisture had condensed on the inside of the chrome steel derby cover and mixed with the oil. With about 10-15 minutes of continued riding, this was all burned off and the oil looked clear. I went ahead and adhered a layer of gasket cork to the inside of that derby cover that is still there after 30 years. It totally stopped that source of condensation and any mayonnaise that I get must be bought from the store (but I don't use it).  

[lucian]

Am I courting disaster by running my 09 griso 8v in cold weather? Is it advisable to let it warm up at idle? Should I periodically pull the cam boxes to inspect for wear or is close monitoring of valve lash adjustment adequate to catch this early? Love this bike, but wont have a bike I cant ride because its cold or damp. Enough questions for now , thanks Dave.      ps I realize there is probably no simple answer to these questions.

[Vasco DG]

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.

Sorry, but the reason I say it's been discussed before is because it has, almost endlessly, in a multitude of threads. Those who are interested will either of seen these ramblings or, if they wish, can do a search here or on any one of a number of boards and get the skinny on how and why I developed my theory as to why the damage occurs and why geographical location is relevant.

It is neither necessary or useful for me to completely re-state every step I have undertaken to analyse and rule out different causes for the failures, hence my comment to Martin that it isn't a clearance option, that was something I ruled out very early in the piece as it was an obvious cause, and yes, I've had the heads off both failed and healthy cammed bikes and there are no signs of valve recession. I've checked most if not all of the *obvious* causes for failure and although I'm only now beginning to get failures through my shop, (As noted after a very cool, damp winter.) I have seen the guts of multiple failed bikes and have had enough experience tearing down 8V engines to know that the manual often lies, (Look at the thermostat in the cooling system issue.) and what happens in various parts of the engine in various temperatures and conditions.

As I've said before I may be quite wrong in my diagnosis but it is at least a diagnosis based on scientific observation, documentation and repeatable results. I've also pestered people world wide for specific information regarding failures on their or their customers bikes. It's been a long, slow haul.

Pete

[Vasco DG]

Am I courting disaster by running my 09 griso 8v in cold weather?

Probably, if you only use it for short trips and don't get it hot enough.

Is it advisable to let it warm up at idle?

No, idling won't warm the oil up in any significant way, the engine has to work to make heat.

Should I periodically pull the cam boxes to inspect for wear or is close monitoring of valve lash adjustment adequate to catch this early?

No point in pulling the camboxes all the time. As soon as wear begins the gaps will open up appreciably, normally 8V's need only tiny adjustments at the 10,000Km service interval. If the gaps open by more than a thou you've probably got a problem. Note also that while it isn't a check that allows 100% certainty observing the tops of the tappets where they poke through the top of the cambox casting is another useful check. When the cam and tappets are healthy with the piston at TDC compression as when you are checking valve lash the tappets are usually ever so slightly proud of the top of the cambox casting, (15-30 thou say.). Once the tappets start to wear the tops will drop to flush or below flush with the top of the cambox. This is clearly visible, even to my old eyes!

Love this bike, but wont have a bike I cant ride because its cold or damp. Enough questions for now , thanks Dave.      ps I realize there is probably no simple answer to these questions.

If you have a FSH and your flat tappets fail then the factory will give you a roller conversion, if the bike is outside of its warranty period you have to pay for installation. If your bike is festooned with aftermarket junk like O2 sensor foolers or Power Commanders, has no name filters and Wally-world oil in it? Forget it!

Pete

[CalVin2007]

  The above photo of the tappets with the DLC missing in the centers interests me. Since DLC is a non-wearing very thin coating I'd think the tappets would be ground absolutely flat and would run on a cam lobe that was also flat (rather than the conventional very slight crowned tappet and tapered cam lobe). No matching "break-in" wear would occur with DLC coatings. SO...my question is: Are the DLC coated tappets and matching cams ground flat or has Guzzi coated tapered parts and caused localized overloading of the tappet resulting in lost DLC in the centers? Once that coating chips it'll be like a lathe cutting the cam lobe down.

  Might be I'm all wet here but that's what crept into my feeble mind this afternoon as I attempt to thaw from this hellish cold spell!

   Terry

[Vasco DG]

I'd considered that and my mind is still open as to it being a contributory factor but it is the timing and geographical nature of the failures that points me away from it as a primary cause.

Pete

[beetle]

Lucian, when running logging runs for map testing in cold weather, I found it takes a very long time (even at 60 mph) to get the 8V up to a 'hot' state of 96C (204F) when you are cruising on the open road. Up to 20 minutes. Now if you are riding slower through town or in a stop/start situation, it may never get hot enough to vaporize water. That's without rain. Water splashing onto the sump exacerbates the situation. The only way to get it not enough was too thrash it. That is high revs at low gear, for a long time. Even then, once returning to cruise, the temp would plummet.

It's my opinion that those who commute in town or stop/start riding all year long through cold weather and rain are in the greatest danger of failure via mayo.

[dddd]

Peter

The failures you have had coming through your workshop, have they been just the older style cast iron tappets or have you been getting the later model forged steel ones as well

[Steph]

Like I said in a previous thread, i think this is a big issue for Piaggio.
& Well done for documenting what you have found so far

http://wildguzzi.com/forum/index.php?topic=70319.msg1106375#msg1106375

[Vasco DG]

There was a 'Technical update', (The recall you have when you aren't having a recall.) on the original cast iron tappets which were only fitted to early A5 motors. By now there should, theoretically, be none left in service.

There certainly was an issue with these, I took some failed ones to the Australian Mint back in '09 or so and had them hardness tested on a Beakers machine and they were found to be wanting but having said that the ones in my bike never failed in 22,000km. I know that the bike before mine suffered an early failure, as did the bike after mine but I put this down mainly to poor prep and negligent servicing, (At this time a lot of shops were still working on the "It's a Guzzi, you can run any old oil in them!" Philosophy and didn't understand the nature of the oil cooling circuit.) I was absolutely anal about stuff like valve clearances during break in and yes, they do close up appreciably when new but even running the original A5 settings of 4 and 6 thou the tappets never rode the cam when hot, yes, I checked, on multiple bikes.

Pete

[lucian]

Thank you Vasco and Beetle for providing concise useful answers to my questions. I know damn well I couldn't have paid my dealer to do the same. You have given myself and others,  a concrete plan in place to deal with these issues in an intelligent manor. I am also gratefull for your permission to flog my griso like a red headed stepchild. Dave

[lucky phil]

 The above photo of the tappets with the DLC missing in the centers interests me. Since DLC is a non-wearing very thin coating I'd think the tappets would be ground absolutely flat and would run on a cam lobe that was also flat (rather than the conventional very slight crowned tappet and tapered cam lobe). No matching "break-in" wear would occur with DLC coatings. SO...my question is: Are the DLC coated tappets and matching cams ground flat or has Guzzi coated tapered parts and caused localized overloading of the tappet resulting in lost DLC in the centers? Once that coating chips it'll be like a lathe cutting the cam lobe down.

  Might be I'm all wet here but that's what crept into my feeble mind this afternoon as I attempt to thaw from this hellish cold spell!

   Terry

The reason for the slight dome on the lifter face along with the lifter bore being slightly off centre with the cam lobe centre line and a slight taper on the cam lobe is to cause the lifter to rotate and present a fresh surface to the cam and promote oil renewal between the surfaces.
There are 2 ways a lifter fails, one is due to oil film loss and the subsequent micro welding pulling the hardening off the face and the other is fatigue.
All of that loading and unloading of the coated or hardened face eventually causes fatigue below the surface and the surface breaks away. Hence the need to still have the lifters rotate to distribute the fatigue evenly.
The same applies to roller bearings, even properly lubricated and protected a roller bearing still has a "life" due to fatigue issues.
Ciao  

[jacksonracingcomau]

I was absolutely anal about stuff like valve clearances during break in and yes, they do close up appreciably

Pete

This, AFAIK there is only one place to lose valve clearance, find it and you have problem solved. If not the valve recessing, where is the clearance going ?

Are all your new failures covered in mayo ?  If so, just after a service suggests some neglect, no-one would put cambox lid back on without cleaning it, surely ?

Old joke but can't stop myself
"Knock, knock"
Who's there ?
Griso

[Vasco DG]

Initially the seats will settle in the heads, there is also stuff like assembly lube that will was out allowing clearances to change, freshly cut seats bed as the valves settle into the margins. Almost all valves will close their gaps in the first few hundred Km/hours of use, some more than others. I would of thought you'd of known that?

Pete

[jacksonracingcomau]

Initially the seats will settle in the heads, there is also stuff like assembly lube that will was out allowing clearances to change, freshly cut seats bed as the valves settle into the margins. Almost all valves will close their gaps in the first few hundred Km/hours of use, some more than others. I would of thought you'd of known that?

Pete

Once marginally is not the issue here, appreciably thereafter might be, can you get to service records of bikes that were just done before they did the trick ?

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.

This new information tells a good story and theory of old oil contaminants being better for DLC is dubious to say the least, can't see not changing oil as the definitive answer.

Generally speaking this is frowned upon


Long bow
When oil is changed it's possible to get air lock in cam feed oil galleries. This can happen on pushrod BB's , starving rockers for a while, normally they self bleed but I have had one that needed bleeding at crankcase.
If this is reason and they self bleed eventually, rollers rocker may be factory's easiest solution, as they possibly withstand dry for the time it takes to bleed gallery.
Are failures always on one side ? (L or R),

Hope Piaggio is covering them all

[Morizzi]

This, AFAIK there is only one place to lose valve clearance, find it and you have problem solved. If not the valve recessing, where is the clearance going ?

Valve stretch? That's where the small blocks normally lose clearance.

Just a thought.  :BEER:

Rod

[Vasco DG]

Considered that too. Yes, I have a variety of half way decent measuring sticks :D

Pete

[youcanrunnaked]

Sorry, but the reason I say it's been discussed before is because it has, almost endlessly, in a multitude of threads. Those who are interested will either of seen these ramblings or, if they wish, can do a search here or on any one of a number of boards and get the skinny on how and why I developed my theory as to why the damage occurs and why geographical location is relevant.

It is neither necessary or useful for me to completely re-state every step I have undertaken to analyse and rule out different causes for the failures....

So, the "it" that has been "discussed before" is the "causes for the failures?"  Not to be rude, but that's not what I asked.  Perhaps you didn't actually read any of my questions?  Only one of them (the second one) touched on the issue of what might be causing the failures, and even that was only in a tangential way.  My other questions had nothing to do with that issue.

I value your insight and experience, so I would really appreciate your consideration of the questions that I actually posed.  As your stated reason for not doing so appears to be a misunderstanding of what I am asking, I will ask one more time.  If there is some other reason why you don't want to answer, well... again, your prerogative to tell me to "bugger off."

[CalVin2007]

The reason for the slight dome on the lifter face along with the lifter bore being slightly off centre with the cam lobe centre line and a slight taper on the cam lobe is to cause the lifter to rotate and present a fresh surface to the cam and promote oil renewal between the surfaces.
There are 2 ways a lifter fails, one is due to oil film loss and the subsequent micro welding pulling the hardening off the face and the other is fatigue.
All of that loading and unloading of the coated or hardened face eventually causes fatigue below the surface and the surface breaks away. Hence the need to still have the lifters rotate to distribute the fatigue evenly.
The same applies to roller bearings, even properly lubricated and protected a roller bearing still has a "life" due to fatigue issues.
Ciao  

      This is true, and I understand it. However, I work daily with a number of diesel engines from a variety of manufacturers and those using tappets with hard coatings or inserts (like the 500 series JD diesel with Carbide disc inserts in the tappets) have no crown and no taper. Only the offset from center to promote rotation. My thoughts are based on these facts as the physics involved seem to fit the pattern of failures seen in some 8V Guzzis.

  Terry

[Vasco DG]

One of my early thoughts was non-rotation of the tappets but if that was the case I would of expected different wear patterns. With your far greater experience of failures of this type I'd be interested in your opinions. I'll drag out a selection of tappets tomorrow and take some pics.

Non rotation wouldn't explain the geographic and climatic pattern to the failures though.

Pete

[CalVin2007]

One of my early thoughts was non-rotation of the tappets but if that was the case I would of expected different wear patterns. With your far greater experience of failures of this type I'd be interested in your opinions. I'll drag out a selection of tappets tomorrow and take some pics.

Non rotation wouldn't explain the geographic and climatic pattern to the failures though.

Pete

     I don't know that I have far greater experience with this type failure,Pete...but I do have occasion to observe how different types of valve train treatments and machining techniques operate and survive. This stuff piques my interest and I appreciate your taking time to post photos of the offending parts. If we don't figure anything out we can always say Bugger It and go drink!

  Terry

[Vasco DG]

  If there is some other reason why you don't want to answer, well... again, your prerogative to tell me to "bugger off."

No, why should I tell you to bugger off? I'm not going to spoon feed you either. All of those questions have been covered extensively over the last few years. If you are really interested you will find the information and subject matter you desire.

Pete (Who forgot to take pics of failed tappets today because he was up to is neck in ot. Sorry.)

[lucky phil]

      This is true, and I understand it. However, I work daily with a number of diesel engines from a variety of manufacturers and those using tappets with hard coatings or inserts (like the 500 series JD diesel with Carbide disc inserts in the tappets) have no crown and no taper. Only the offset from center to promote rotation. My thoughts are based on these facts as the physics involved seem to fit the pattern of failures seen in some 8V Guzzis.

  Terry

I see your point but you know not everything translates exactly. I'll make an assumption that the diesel engines you refer to are a direct injection type of large capacity that probably rev to 2700 rpm or there abouts, might be wrong but if so it doesn't necessarily follow that an engine with a much wider operating rpm range that can spin to 8000 rpm can get away with the same design of lifters and cam lobes
Ciao

[MotoG5]

Keep the info coming Pete. I love my NTX and have had two years of great riding. Armed with the information you and others are providing I can monitor my flat tappets and cam condition and possibly catch an insipient failure before major damage IF it ever comes to that. Piaggio has already stated that the roller kit will be provided free of charge to anyone who has this issue even if the bike is out of warranty. I am confident I can do the install myself. I am sure as heck not going to sell the bike for a loss and go out and spend thousands more on some other brand to replace it just in case the problem MIGHT happen. Or spend the cash out of pocket for the kit and replace it just in case. If I can get 40 or 50k miles out of the current set up I have already paid for good enough. At least I will have gotten that much out of it before investing any more to keep on the road. During the mean time I will have had time to see how the new roller set up works out or who knows maybe there will be a new design change down the road that's better. No matter for me, the bike is paid for and I may as well roll with what ever comes to keep riding it. ;-T

[youcanrunnaked]

No, why should I tell you to bugger off? I'm not going to spoon feed you either. All of those questions have been covered extensively over the last few years....

Oh, brother!  How could my questions have been answered "extensively over the last few years" when I am specifically asking about the failures THAT YOU HAVE PERSONALLY WITNESSED COMING THROUGH YOUR SHOP  -- failures that you first reported here on November 17, 2014 (three days ago)?

Moreover, the question that has been "covered extensively" is the source of these failures.  I DIDN'T ASK THAT QUESTION.  

I am not asking to be "spoon-fed."  If you know anything about how I operate, I am perfectly capable of looking up available information.  However, you state that you are finally dealing personally with 8V failures in your shop, and that this is a recent phenomenon.  For questions such as whether the failed 8V bikes that are in your shop now or you have recently seen are in or out of warranty, and whether Piaggio is covering all or part of the expense of repairs (and what that repair and expense entails), who else but you should I ask, and how else except by asking you now could I find the answers?

So, to be clear, FOR THE 8V FAILURES THAT YOU FIRST REPORTED HERE THREE DAYS AGO (and ONLY in regard to those bikes):

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?


FWIW, I am not asking out of idle curiosity, but to inform future purchasing decisions.

[BlizzGuzz]

So, to be clear, FOR THE 8V FAILURES THAT YOU FIRST REPORTED HERE THREE DAYS AGO (and ONLY in regard to those bikes):

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?


FWIW, I am not asking out of idle curiosity, but to inform future purchasing decisions.

 ;-T
I'm also very interested in answers to these questions.   

[Vasco DG]

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?


FWIW, I am not asking out of idle curiosity, but to inform future purchasing decisions.

OK, I'll waste a bit more time for you.

1.) Several.

2.) No idea, I wasn't riding them.

3.) No.

4.) No.

5.) This has been explained a dozen times.

6.) Replacement of the camboxes with roller assemblies. Depending on motor the heads may need to come off to shim the inlet valve springs.

7.) AFAIK there have been no systemic failures of roller top ends but there again they haven't been around that long.

I strongly advise you don't buy one. You'd never enjoy it because you would always be anticipating some sort of failure. Where's the fun in that.

OK. Questions answered. Happy?

Pete

[Aaron D.]

This is fun!
If nothing else, Pete, at least everyone now realises that flat tappets are not just a pushrod thing.

Hey, what are the cam bearings, roller or plain? Any damage there? I have some relevant experience with cam failures like this that started with bearings getting smushed at cold-start due to high pressures on certain bearings. The bearing damage blocked the oil feed, which restricted flow to the cam lobe. Engines with fewer cold starts lasted many miles longer than engines in short commuting service. I have pictures...

[Vasco DG]

Cam bearings are plain, fed from high pressure circuit, no damage, always plenty of oil in evidence.

Pete

[lucian]

Pete, I'm curios if any of the failed 8v's you are encountering will be upgraded to roller tappets, if so can we hope for a tutorial? Also are you seeing this both in a5 and a8 motors? Dave