Author Topic: Guzzi 8V tappet failure. WHY, and why not others?  (Read 18966 times)

Offline bsanut

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Guzzi 8V tappet failure. WHY, and why not others?
« on: December 22, 2015, 04:28:58 PM »
So if this is explained in another thread, sorry.  But with SO many conversations regarding the non-roller 8V engines, I'm curious as to WHY the Diamond-Like-Coating was used, if what was working before was....working?

The Britbikes used stellite, whatever that is.  What does/did Guzzi use as a tappet surface on the pushrod bikes?  The Centauro/Daytona engines?

And for that matter, why does Guzzi seem to have SO MUCH TROUBLE with new valve train designs?  It seem like that kind of stuff should be old-school engineering by now.

But I'm not that great a mechanic, and certainly not an engineer, so explain somebody...

Joe
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Offline lucian

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #1 on: December 22, 2015, 04:38:08 PM »
Man , I hope Pete's in a good mood. :laugh:

Offline HDGoose

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #2 on: December 22, 2015, 05:15:44 PM »
I am assuming lowest bidder. And since 80-90% are good, corporations say screw the rest.

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #3 on: December 22, 2015, 05:57:18 PM »
As you say it has been covered in numerous other threads over the last seven years. I have reiterated my views and reviewed my opinions as new research had validated or discredited my suggestions. I've had considerable help from people who are a lot better qualified than me but they choose to remain anonymous which is fine. I feel that there is little to be gained by constantly groundhog day-ing the whole wretched topic. I think I have a pretty good idea why the DLC fails and why it wasn't a very good idea but every time I've explained and supplied references they are generally ignored and I simply get trolled so it really isn't worth me wasting my life on.

As it is I am now more focused on trying to get the problem rectified with as little grief and expense as I can for as many people as possible. Anybody else is more than welcome to continue to isolate the cause and prove me wrong. I care not.

Pete

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #3 on: December 22, 2015, 05:57:18 PM »

canuguzzi

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #4 on: December 22, 2015, 06:46:15 PM »
Why it happened is irrelevant, what does it matter unless it is a failure to perform maintenance or abuse in operation?

Who really cares what causes a coating to flake off, peel off or get worn off? The only people that can fix it are the ones who screwed it up and they want those who paid for the bikes to be the ones who pay to fix it too.

It isn't about passion, love of the marque, loyalty to a brand, understanding and empathy for people or anything else, it is business. Some will want to make it personal with others, it is not, its money and business unless it is impossible to separate the motorcycle from the person. Oh well.

The business is who will end up paying for the fix? End up is the key because it has come to push or shove and in the end, nothing anyone here says means much, it's past that. Someone else will decide and it will be one of three entities:

The company voluntarily or;

Some agreement  between a few and the company and affecting individuals or all those who bought an affected bike or;

Some government agency or a court and affecting all those who bought an affect bike even if they paid out of pocket to fix it.

It won't matter one bit who on this forum says what nor any opinions, speculation or theories about why it happened.

The wheels are in motion, just a matter of where they stop. The end.

Offline smdl

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #5 on: December 22, 2015, 08:51:03 PM »
I just noticed that the "ignore" feature seems to be gone.  I've never used it before, at least not intentionally.  Did it disappear with the upgrade to the current version, or am I just missing it?

Thanks -- sorry for the OT comment.

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Online Bisbonian

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #6 on: December 22, 2015, 09:45:05 PM »
I just noticed that the "ignore" feature seems to be gone.  I've never used it before, at least not intentionally.  Did it disappear with the upgrade to the current version, or am I just missing it?

Thanks -- sorry for the OT comment.

Shaun
Profile - account settings - modify profile - ignore/buddy list.

Offline smdl

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #7 on: December 22, 2015, 10:05:00 PM »
Profile - account settings - modify profile - ignore/buddy list.

Thanks!  Again, sorry for the interruption!

Shaun
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Offline molly

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #8 on: December 23, 2015, 06:08:46 AM »
So if this is explained in another thread, sorry.  But with SO many conversations regarding the non-roller 8V engines, I'm curious as to WHY the Diamond-Like-Coating was used, if what was working before was....working?

The Britbikes used stellite, whatever that is.  What does/did Guzzi use as a tappet surface on the pushrod bikes?  The Centauro/Daytona engines?

And for that matter, why does Guzzi seem to have SO MUCH TROUBLE with new valve train designs?  It seem like that kind of stuff should be old-school engineering by now.

But I'm not that great a mechanic, and certainly not an engineer, so explain somebody...

Joe

Newcomers to the subject are entitled at ask questions because it has been a long tale of woe that unless you were in on from the beginning is very difficult to grasp.
Basically Guzzi designed a new 8 valve motor to replace their traditional 2 valve big block engine and for some undeclared reason made a design error that resulted in excessive valve train wear.
 Different sticking plaster solutions including lastly DLC were attempted with no success until the roller version was released. You probably need to google DLC coatings on engine components to get a better picture but here is a starter.

https://www.researchgate.net/publication/223598544_Impact_wear_testing_of_diamond-like_carbon_films_for_engine_valve-tappet_surfaces

Note the relevance to valve train impact loading on the durability of DLC.  Which could suggest the 8 valve design suffered from excessive impact loading.

There has been no factory communique on the subject so it has been left to individuals to try and explain the cause which at present it still unclear as any theory cannot be verified by the factory.
Why  Guzzi got the design so wrong is anybodies guess, they are not the first company to make such errors and probably won't be the last. Would they mismanage the all important remedial solutions so badly again only time will tell.

These are just my musings please don't get on my back,  I know it is an emotive subject.
Dave

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Offline bsanut

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #9 on: December 23, 2015, 01:10:50 PM »
I guess I didn't ask the question properly.  I was hoping to understand why other tappets DIDN'T fail, not so much why the DLC DID.

And what surface treatment used in the past, and why the change to DLC if it didn't have issues.  But I guess I'll just let this die.

Joe
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Offline bsanut

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #10 on: December 23, 2015, 01:15:06 PM »
Should have read a little deeper first.  So the DLC came with the 1st recall of the flat tappet 8Vs?  It was a 'fix' for the first bad setups of '08/'09?

Joe
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Online Wayne Orwig

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #11 on: December 23, 2015, 04:04:09 PM »
Should have read a little deeper first.  So the DLC came with the 1st recall of the flat tappet 8Vs?  It was a 'fix' for the first bad setups of '08/'09?

Yes, it was the 'fix'.

Oops..... :weiner:

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Offline MotoG5

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #12 on: December 23, 2015, 09:10:21 PM »
Newcomers to the subject are entitled at ask questions because it has been a long tale of woe that unless you were in on from the beginning is very difficult to grasp.
Basically Guzzi designed a new 8 valve motor to replace their traditional 2 valve big block engine and for some undeclared reason made a design error that resulted in excessive valve train wear.
 Different sticking plaster solutions including lastly DLC were attempted with no success until the roller version was released. You probably need to google DLC coatings on engine components to get a better picture but here is a starter.

https://www.researchgate.net/publication/223598544_Impact_wear_testing_of_diamond-like_carbon_films_for_engine_valve-tappet_surfaces

Note the relevance to valve train impact loading on the durability of DLC.  Which could suggest the 8 valve design suffered from excessive impact loading.

There has been no factory communique on the subject so it has been left to individuals to try and explain the cause which at present it still unclear as any theory cannot be verified by the factory.
Why  Guzzi got the design so wrong is anybodies guess, they are not the first company to make such errors and probably won't be the last. Would they mismanage the all important remedial solutions so badly again only time will tell.

These are just my musings please don't get on my back,  I know it is an emotive subject.

Actually a very good concise and accurate summation of this event. :thumb: I have a self rollerized 2012' NTX sitting out in my garage so have been in this deal from the start. I did in the end get reimbursed by Piaggio for the kit but only because of my dealers support and the fantastic Guzzi people who love and support these bikes. They have made it possible for me to do what it took to get it fixed. Why it happened is at this time is a point of interest that I will of course follow as an interesting mechanical engineering exercise. As for the emotional aspect the 8V twin is a soulful gas to ride and well worth the price of admission. :cool: 
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Offline jacksonracingcomau

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #13 on: December 23, 2015, 10:21:05 PM »
First a little background on the area, this part of Northern Italy has been inhabited for 10's of thousands of years, many of the local people can lay legitimate claim to being truly native, an ancient and noble people , one of the first cultures in the world to use the written word. They were and still are not happy to be ruled by Rome, under the facade of a Roman Catholic society lies some deep rooted beliefs and superstitions.

Carlo Guzzi and Alberto Camero were both of such history and one of the pacts they made as tribal cousins was that certain pieces of Carlo's creations would be designed and manufactured by Camero, including but not limited to all valve train components, breather systems and final drives. Camero's genius in this field led to his company growing to be the only camshaft producing industry in Italy, designing and supplying all motorcycle, car and truck manufacturers, winning a number of world championships no-one can best, not even Michelin. But that was in the future.

Jump to December 1921, the war was nearly forgotten, Alberto was working feverishly for Guzzi, he'd completed and test run his DOHC 4 valve per cyl 70deg twin, this was going to blow the world into the weeds.
T'was the night before Xmas, Alberto returned home from the factory late as usual , only to see shadows in the firelight. His jaw dropped as he peered through his own window. His beautiful new young wife covorting naked not with one but with two of the Guzzi clan.
He took his own life that night but not before returning to his factory to destroy all evidence of the DOHC rocketship, the plans and tooling all gone. Finally he painted in the ancient script in blood on the factory wall
"A curse on Guzzi and all that will work there, never can they build a mutlivalve engine that will work"

Of course, such things were taken a bit more seriously then and Guzzi , by way of honour, used only 2vpc. Camero's design for their pushrod  driven OHV 500 single lasting 50 odd years, race winning and bulletproof. The 67 V twin used essentially the same design and proved itself, although mysterious batches of flawed cam followers showed up periodically. These were not sourced elsewhere as is often thought but were a direct action against De Tomasso's engineers who made but never actually sold a pushrod/forked rocker set up for 4vpc in big block engine. The ju-ju worked

The 80's and 90's saw the ju-ju spill. The Lario and it's brother the V75 incurred Alberto's wrath, the models sent to an early grave, taking Guzzi reputation down a peg or two

Why they didn't listen to the townsfolk of Mandello, we'll never know but the Daytona/Centauro followed the Lario, both to the workshop and the early grave.

Quietly reverting to the 2vpc engines that they were allowed by Alberto to build, nearly 20 years of calm and total reliability ensued. The memory of the 4vpc attempts enough to convince anyone that Alberto's curse was and is real.

Enter Piaggio, their engineers, as devout Catholics, dismissed the fairy story, built a new 8V V twin around the old cases and sold it

Ju -ju spilling everywhere, these things defied belief, cams and followers turning to dust all over the world. A little ju-ju fell on the new CARC system, various other stuff too

The engineers scratched their nuts and looked for answers, unbelievably trying to test Alberto by going outside Italy for camshafts and followers. They found a supplier in China (These people had similar ancient history and could put Alberto's curse to rest, so they said) to confuse the punter the new cam follower would be of the "roller' type, neatly explaining how all made before it were of faulty design not product, and most definitely not because of ju-ju.

This is when Alberto's curse goes right off
In designated areas, certain market and weather conditions perhaps, he let loose the ju-ju big time
Just some (so far) of the original bikes that have had the Chinese cams and followers fitted, he let the ju-ju run right through the engine, attacking big end shells and crankshafts, sending complete engines to the eternal scrapheap.


More as it happens

Happy Xmas, one and all

Offline Aaron D.

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #14 on: December 24, 2015, 06:26:35 AM »
Now THAT makes sense! Thank you!

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #15 on: December 24, 2015, 07:50:36 AM »
Finally, an explanation I can wrap my head around!
I just knew the smoking gun component of these failures had not yet
been revealed. Thanks.
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Offline Jim Rich

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #16 on: December 24, 2015, 08:11:17 AM »
Yes, excellent explanation, I especially like the socio/political/religous bs, I mean parts, that ties it back to my experience with old british twins that had all kind of interesting juju and myths attached to them.  Thanks 

Offline molly

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #17 on: December 24, 2015, 08:31:54 AM »
You've copied the ju ju explanation from some secret Guzzi web site haven't you? Probably only available to persons who were educated at Hogwarts.
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yrunvs

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #18 on: December 24, 2015, 09:20:39 AM »
Somewhere in the story Alberto declared "And let there be mayonnaise!"

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #19 on: December 24, 2015, 10:29:58 AM »
Well, that should put the whole thing to rest. Makes perfect sense, now..   :grin:
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Offline lucian

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #20 on: December 24, 2015, 12:22:40 PM »
Fascinating. Said Mr Spock.

Looks like the eggnog 's got a little extra kick to it this year. :laugh:
« Last Edit: December 24, 2015, 12:25:00 PM by lucian »

Offline steven c

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #21 on: December 28, 2015, 09:11:48 AM »
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Online Wayne Orwig

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #22 on: December 28, 2015, 11:25:35 AM »
Suzuki does the right thing. Recall on valve and tappet,cam wear.
http://blog.motorcycle.com/2015/12/24/manufacturers/suzuki/multiple-suzuki-models-recalled-for-valve-tappet-and-cam-wear/

Interestingly, they word it almost like Moto Guzzi already is. Basically, they only replace the parts IF they are wearing. (or they will replace them on a nearly new machine)
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Offline DCWCALI

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #23 on: December 28, 2015, 12:20:13 PM »
First a little background on the area, this part of Northern Italy has been inhabited for 10's of thousands of years, many of the local people can lay legitimate claim to being truly native, an ancient and noble people , one of the first cultures in the world to use the written word. They were and still are not happy to be ruled by Rome, under the facade of a Roman Catholic society lies some deep rooted beliefs and superstitions.

Carlo Guzzi and Alberto Camero were both of such history and one of the pacts they made as tribal cousins was that certain pieces of Carlo's creations would be designed and manufactured by Camero, including but not limited to all valve train components, breather systems and final drives. Camero's genius in this field led to his company growing to be the only camshaft producing industry in Italy, designing and supplying all motorcycle, car and truck manufacturers, winning a number of world championships no-one can best, not even Michelin. But that was in the future.

Jump to December 1921, the war was nearly forgotten, Alberto was working feverishly for Guzzi, he'd completed and test run his DOHC 4 valve per cyl 70deg twin, this was going to blow the world into the weeds.
T'was the night before Xmas, Alberto returned home from the factory late as usual , only to see shadows in the firelight. His jaw dropped as he peered through his own window. His beautiful new young wife covorting naked not with one but with two of the Guzzi clan.
He took his own life that night but not before returning to his factory to destroy all evidence of the DOHC rocketship, the plans and tooling all gone. Finally he painted in the ancient script in blood on the factory wall
"A curse on Guzzi and all that will work there, never can they build a mutlivalve engine that will work"

Of course, such things were taken a bit more seriously then and Guzzi , by way of honour, used only 2vpc. Camero's design for their pushrod  driven OHV 500 single lasting 50 odd years, race winning and bulletproof. The 67 V twin used essentially the same design and proved itself, although mysterious batches of flawed cam followers showed up periodically. These were not sourced elsewhere as is often thought but were a direct action against De Tomasso's engineers who made but never actually sold a pushrod/forked rocker set up for 4vpc in big block engine. The ju-ju worked

The 80's and 90's saw the ju-ju spill. The Lario and it's brother the V75 incurred Alberto's wrath, the models sent to an early grave, taking Guzzi reputation down a peg or two

Why they didn't listen to the townsfolk of Mandello, we'll never know but the Daytona/Centauro followed the Lario, both to the workshop and the early grave.

Quietly reverting to the 2vpc engines that they were allowed by Alberto to build, nearly 20 years of calm and total reliability ensued. The memory of the 4vpc attempts enough to convince anyone that Alberto's curse was and is real.

Enter Piaggio, their engineers, as devout Catholics, dismissed the fairy story, built a new 8V V twin around the old cases and sold it

Ju -ju spilling everywhere, these things defied belief, cams and followers turning to dust all over the world. A little ju-ju fell on the new CARC system, various other stuff too

The engineers scratched their nuts and looked for answers, unbelievably trying to test Alberto by going outside Italy for camshafts and followers. They found a supplier in China (These people had similar ancient history and could put Alberto's curse to rest, so they said) to confuse the punter the new cam follower would be of the "roller' type, neatly explaining how all made before it were of faulty design not product, and most definitely not because of ju-ju.

This is when Alberto's curse goes right off
In designated areas, certain market and weather conditions perhaps, he let loose the ju-ju big time
Just some (so far) of the original bikes that have had the Chinese cams and followers fitted, he let the ju-ju run right through the engine, attacking big end shells and crankshafts, sending complete engines to the eternal scrapheap.


More as it happens

Happy Xmas, one and all

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Offline Waterbottle

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #24 on: December 28, 2015, 04:19:01 PM »
Ju Ju ?  :laugh:
I'm going to use a clean towel and some WD40  to clean off any residual Ju Ju left over from the last ride  :grin:
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Offline jacksonracingcomau

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #25 on: January 09, 2016, 03:36:36 AM »
Somewhere in the story Alberto declared "And let there be mayonnaise!"
And that made huge sense, certain markets & conditions, I had my head around that
Fuel to disprove the "Alberto" story. Actually his real name was Alberro but that's another story

Speaking to old Guzzisti mate today of a bloke he swears I know but,,,,,,,,,

Has 8V Griso engine, one of first, he has the DLC tappets but not fitted
Was FIFO worker, lives in SW WA, 1400Km (900 odd m) to airport, girlfriend north of Perth 2200Km from home. Job was 4600Km
Sometimes he did whole trip, stopping at girl's on way, sometimes he flew
Anyway, thing's done 250,000 Km apparently only apart when he first got it-- made some noises that no -one would live with.

I'l get the full SP at Easter, he'll be at Broadford Bonanza (so will the factory V8)
But look out for Tonti 8V, Aussies, is a bit special apparently,

If true, Pete was prob right all along, on both counts

Was markets & conditions, this engine only ever run hot
No-one should consider riding with an engine that sounds like it wants to break, it probably will

canuguzzi

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #26 on: January 09, 2016, 10:26:18 AM »
Juju probably is the problem:

www.jujuaroma.com

An oil for dry flaky skin. Apparently it doesn't fix dry flaky DLC.

Offline organfixsing

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #27 on: January 11, 2016, 05:58:37 AM »
I seem to remember, in Phil Irving's 'Tuning For Speed' that the tappets should be designed so that they rotate at every cam contact, that is , the cam would be slightly offset to the centre on the tappet. Is this not the case with these tappets?
Cheers
Brian    :grin:
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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #28 on: January 11, 2016, 06:14:49 AM »
I seem to remember, in Phil Irving's 'Tuning For Speed' that the tappets should be designed so that they rotate at every cam contact, that is , the cam would be slightly offset to the centre on the tappet. Is this not the case with these tappets?
Cheers
Brian    :grin:

(Sigh!) The technology has changed, the tappets now rotate via a small angle on the grind rather than convex faces on the tappets. This had to be done due to the nature of the DLC coating, how it is applied and how it works.

Mr. Irving's book is a great tome and still contains a lot that is relevant. Unfortunately it also contains a lot of information that has been superceeded by advances in design, materials and maufacure in the last half a century. It is no longer the 'Go To' it once was.

FWIW it seems that BMW are having similar de-lamination problems with the DLC coating on their four cylinder motors. I assume these are the buckets the cam lobes ride on seeing as it is a conventional DOHC design. It seems that it is just not a viable technology for this application.

Pete
« Last Edit: January 11, 2016, 06:29:23 AM by Vasco DG »

Offline Gliderjohn

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Re: Guzzi 8V tappet failure. WHY, and why not others?
« Reply #29 on: January 14, 2016, 03:14:56 PM »
Well I have decided to roller my 2011 Norge regardless. Not doing anything appears to be a real crap shoot. Having it inspected is pretty much the same labor costs as the inspection only. If wear is found and Guzzi throws in the kit, great. If no wear showing at this time putting the kit in anyway will give me much more piece of mind but also make me much more gun shy in the future to buy a new Guzzi product.
GliderJohn
John Peters
East Mountains, NM

 

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