Wildguzzi.com
General Category => General Discussion => Topic started by: jlburgess on October 20, 2015, 08:56:12 AM
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:popcorn:
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I have the factory supplied roller tappets in my engine. The '12 Stelvio was built in Feb 2012, bought in June 2012. It now has 32K miles on it and I just did the service work, including a valve clearance check. All readings were where they should be -- '006" Intakes, '008" Exhausts. The bike has been running great.
Ride safe out there.
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I have the factory supplied roller tappets in my engine. The '12 Stelvio was built in Feb 2012, bought in June 2012. It now has 32K miles on it and I just did the service work, including a valve clearance check. All readings were where they should be -- '006" Intakes, '008" Exhausts. The bike has been running great.
Ride safe out there.
With the roller tappets, do you see much change in clearances when you check them?
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Just had mine inspected at 32k miles - 2012 Stelvio
No issue - but this is Houston so limited cold weather condensation
....now to go check my swing arm, luckily my son does NDE for a living :thewife:
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Recently did the roller conversion on my 2012 Norge with 3500 miles. The flat tappet surfaces showed the beginning of breakdown of the DLC. I'll try to post a couple of pictures later -- I didn't really expect to see any breakdown of the DLC, but even with so few miles, it was starting to happen ....
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Recently did the roller conversion on my 2012 Norge with 3500 miles. The flat tappet surfaces showed the beginning of breakdown of the DLC. I'll try to post a couple of pictures later -- I didn't really expect to see any breakdown of the DLC, but even with so few miles, it was starting to happen ....
Was anything covered by Piaggio?
I just talked to the importer about my 2009 Griso. If I thought I had a case I'd have to provide them with documentation, any reimbursement of a roller tappet conversion would be considered case by case. No surprise about that.
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No. In my case, I purchased the bike used, with an unknown service history, and no warranty left. I just decided to do the conversion on my dime --
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I have the factory supplied roller tappets in my engine. The '12 Stelvio was built in Feb 2012, bought in June 2012. It now has 32K miles on it and I just did the service work, including a valve clearance check. All readings were where they should be -- '006" Intakes, '008" Exhausts. The bike has been running great.
Ride safe out there.
I thought that the roller tappet settings were .004" and .006". :huh:
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Factory rollers. Valves remain in spec for two adjustment periods.
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More information for the collective knowledge on the flat tappet issue:
(http://i1383.photobucket.com/albums/ah305/mgregomail/DSC_0208_zpssugon4nm.jpg)
2012 8V Norge tappets, 3500 miles
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With the roller tappets, do you see much change in clearances when you check them?
Wayne,
I check them regularly at 6K intervals, or a bit earlier if I'm ready to go out on a trip. Oil and filter get changed at the same time. I've got all of the records but, as I recall, the clearances have not changed, either up or down, more than .001" on any of the intervals. This last check, just done this past week, was the only one where all readings were right where they were set. Apparently, they finally seated in.
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I thought that the roller tappet settings were .004" and .006".
Moto,
I'm just going on what Jim B. at Rose Farms told me -- .006" Intakes, .008" Exhausts -- for the roller tappet 8V engines.
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The 8V bikes seem a bit strange in that the clearances open up appreciably as the engine heats up. I've experimented with going down to 2 and 4 and it still behaves itself when hot because whipping the cover off and checking them as quick as possible I was still finding them at five and eight when hot.
I suggest 4 & 6 for safety and quietness.
Pete
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:bike-037:
Recently did the roller conversion on my 2012 Norge with 3500 miles. The flat tappet surfaces showed the beginning of breakdown of the DLC. I'll try to post a couple of pictures later -- I didn't really expect to see any breakdown of the DLC, but even with so few miles, it was starting to happen ....
Does the factory DLC coat the tappets? Another question, do you have any way to check the Rockwell hardness of the tappet face?
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:bike-037:
Does the factory DLC coat the tappets? Another question, do you have any way to check the Rockwell hardness of the tappet face?
No, but the Australian Mint does and that's where I got the original chilled cast iron tappets tested. They were, in some cases, not hard enough. You can't use a Beakers machine on DLC as its a penetrative test not a density test.
Pete
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No, but the Australian Mint does and that's where I got the original chilled cast iron tappets tested. They were, in some cases, not hard enough. You can't use a Beakers machine on DLC as its a penetrative test not a density test.
Pete
Ok, thanks for the info. I am working with some H13 hot work tool steel, making tappets for a project V7. Hardening to 50-51 Rockwell to match the factory hardness. Following the tappet failure thread with great interest.
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Ok, thanks for the info. I am working with some H13 hot work tool steel, making tappets for a project V7. Hardening to 50-51 Rockwell to match the factory hardness. Following the tappet failure thread with great interest.
I've spent a lot of time communicating with people a lot cleverer and better educated than myself on this issue, as I often say I'm just a facilitator and communicator but I DO try and do the research. If people ask me at the time I can probably post links to some of the wordy and mainly tedious papers that have been written by boffins on these subjects but really it isn't probably worth it.
The gist of the matter though is there are problems getting DLC to adhere to a ferrous substrate and also because of its frangible nature flexing of that substrate during use may cause the coating to craze and shatter. This issue can be exacerbated by the use of incorrect lubricants or certain additives.
External environmental issues such as moisture, heat and incorrect servicing are another dead fish that has to be thrown into the mix. NO I don't have 'The Answers' but I'll bet you a bus full of beehives I've done a damn sight more research and testing on this issue than just about anyone else outside the factory. Does that mean my suppositions are right? No, but the scientific method requires that peer review disprove my findings rather than just being shouted at by blockheads who haven't got a clue and just want to pile on.
Pete
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I suppose it is possible the DLC just can't cope with the impact of the cam as it leaves and returns to the tappet.
http://www.sciencedirect.com/science/article/pii/S0043164810000505
The above is from Leicester university (UK) department of engineering.
I am losing the plot a bit here, was DLC applied after the intial failures?
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I am losing the plot a bit here, was DLC applied after the intial failures?
That is my understanding. It was an attempt to fix the issues fist encountered. When it became apparent that it did not work the change over to rollers was quietly instituted.
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The tappet material was changed and the DLC coating added. Early tappets were batched produced chilled cast iron, later ones are forged steel with DLC coating. Foot shape of tappet and possibly radiusing changed with the V2 tappets. I believe, although I've not managed to confirm, that the V1 tappets were radiused for spin whereas the V2, DLC coated tappets are flat but the cam profile is angled ever so slightly in section. NOTE. I say this is something I haven't been able to accurately confirm!
I don't think it is the fault of the DLC. I think it's a combination of issues one of which will be the fairly major stresses imposed on the tappets by the somewhat aggressive cam profiles. Interestingly though on the cams themselves the major manifestation of damage during early detected failure is on the nose circles of the cams, not on the ramps or opening flanks where you would expect them to be.
Pete
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O.k. I get that, DLC obviously didn't solve a problem that already existed and was probably a last ditch attempt prior to rollers.
So what makes the 8v tappet/cam relationship on the 8v motor so different to other engines that it constantly wears hardened or DLC coated components.?
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Ok, thanks for the info. I am working with some H13 hot work tool steel, making tappets for a project V7. Hardening to 50-51 Rockwell to match the factory hardness. Following the tappet failure thread with great interest.
Wow..that's not very hard. I would think they should be at least RC 56-58? Disclaimer.. I'm certainly *not* an engine designer, but I've heat treated a ton of tool steels. Probably more than that, actually.. :smiley:
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Wow..that's not very hard. I would think they should be at least RC 56-58? Disclaimer.. I'm certainly *not* an engine designer, but I've heat treated a ton of tool steels. Probably more than that, actually.. :smiley:
Apologies in advance for the thread drift...
Tested two Lario tappets, both at 52 Rockwell. Checked later model new Guzzi tappets, same value.
The H13 cool down is at 1000 degrees F. I can go harder, but I'm trying to match the factory spec.
We will see how they hold up...
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Apologies in advance for the thread drift...
Tested two Lario tappets, both at 52 Rockwell. Checked later model new Guzzi tappets, same value.
The H13 cool down is at 1000 degrees F. I can go harder, but I'm trying to match the factory spec.
We will see how they hold up...
Oh, I understand, I would too.. it just surprises me. I've never personally heat treated H13, so it may be a completely different animal. For wear, we used to shoot for RC 56. Back in the Pliocene, when Pete was first investigating cam failures, he was finding RC 45. Now, I *know* that isn't hard enough. That's spring hardness..
Ok, did a little research, and H13 seems to be a strange alloy *to me* for this application. It's generally used to make die cast molds. I thought it sounded familiar..and yes, it's a completely different animal. I would have thought they would use a shock and wear resistant alloy like S7 for something like cam and lifters. That needs to be around RC 56. <shrug>
Live and learn.. :smiley:
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Oh, I understand, I would too.. it just surprises me. I've never personally heat treated H13, so it may be a completely different animal. For wear, we used to shoot for RC 56. Back in the Pliocene, when Pete was first investigating cam failures, he was finding RC 45. Now, I *know* that isn't hard enough. That's spring hardness..
Ok, did a little research, and H13 seems to be a strange alloy *to me* for this application. It's generally used to make die cast molds. I thought it sounded familiar..and yes, it's a completely different animal. I would have thought they would use a shock and wear resistant alloy like S7 for something like cam and lifters. That needs to be around RC 56. <shrug>
Live and learn.. :smiley:
For the rest of us, would it be fair to say that it isn't just a matter of the DLC but the material the tappets are made from and that the flat design might work just fine were different materials used to make the tappets? Just for discussion of course.
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I'm normally just a lurker here. Enjoy the banter, but not much for communicating by type. Anyway, I have experience in tooling systems and precision tool making that gives me info that is pertinent here. The term "DLC" is really pretty generic. There are a bunch of coatings that would fit that description with different capabilities and hardness. In this application, it would be a "PVD" type coating that is applied at around 900 deg F (possibly lower depending on the coating system). The question I've had is just because the coating is gone, it doesn't necessarily mean the tappet is damaged - only that the coating didn't adhere, and that is a pretty normal failure mode. The problem usually is the cleanliness of the surface that it's applied to. So when the coating is gone, has anyone actually inspected the tappet surface for wear? Any good tool maker could indicate that surface and tell you with in tenths of a thousandths (for us imperial guys) whether that surface is scarred or not. Actually the cam could be done also with more effort. Has that ever been done? If not, I can do it if someone can provide the components.
For the record - mines got 24K miles on it and I check clearances twice a year whether it's time or not and haven't made an adjustment more than a thou / thou and a half ever.
Ride Safe,
Jeff
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Once the wear reaches a critical point it all goes very bad very quickly and the parent material of the tappet vanishes rapidly.
Pete
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For the rest of us, would it be fair to say that it isn't just a matter of the DLC but the material the tappets are made from and that the flat design might work just fine were different materials used to make the tappets? Just for discussion of course.
Well, I've never designed an engine, but I have designed and built many machines. I wouldn't think of using a mold steel for something like a cam or cam follower. Maybe that is what is commonly used? *I don't know.* H 13 is a high chrome alloy, and would have good rust resistance. That is certainly important..
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Well, I've never designed an engine, but I have designed and built many machines. I wouldn't think of using a mold steel for something like a cam or cam follower. Maybe that is what is commonly used? *I don't know.* H 13 is a high chrome alloy, and would have good rust resistance. That is certainly important..
I am still in the experiment stage. Will PM you the details Chuck. Using the H13 for the pushrods cups that are pressed into the lifter bodies so that shorter pushrods can be used. It is the same hardness as the stock cups after heat treat, and has excellent wear resistance.
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Once the wear reaches a critical point it all goes very bad very quickly and the parent material of the tappet vanishes rapidly.
Pete
That's the downside to coatings, they are thin and once compromised game over. I'm sure Guzzi would have chosen materials in the original design which normally would have been expected to do the job, we have to give them some credit I suppose.
The puzzling thing for me is besides not knowing why the excessive wear is taking place is that the factory did not pick it up in the development stage. They manufacture a limited number of engines so it is not as if they were distracted by numerous other engine projects. Unless it was a Aprilia design.
I would love to be a local in the factory watering hole and after a few beers and a few loose tongues, getting the real low down on the matter.
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So when the coating is gone, has anyone actually inspected the tappet surface for wear? Any good tool maker could indicate that surface and tell you with in tenths of a thousandths (for us imperial guys) whether that surface is scarred or not. Actually the cam could be done also with more effort. Has that ever been done? If not, I can do it if someone can provide the components.
Once the DLC was gone, mine opened another 0.002" in 200 miles. The cam was damaged, but only very slightly. The tappet is pretty soft metal under that DLC. And visually you could see the gouge, though I didn't try to measure it.
Still waiting in kit C.
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Wayne - I may have missed this, but what kind of mileage did you have on yours and what type of oil (and / or any additives) were you running.
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Trophy, this has all been covered innumerable times in several threads, do a search and you'll find your answers. The ZDDP issue is a red herring.
Pete
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So this is only with 8V motors? All models? When did they make the change? Thanks
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That's the downside to coatings, they are thin and once compromised game over. I'm sure Guzzi would have chosen materials in the original design which normally would have been expected to do the job, we have to give them some credit I suppose.
The puzzling thing for me is besides not knowing why the excessive wear is taking place is that the factory did not pick it up in the development stage. They manufacture a limited number of engines so it is not as if they were distracted by numerous other engine projects. Unless it was a Aprilia design.
I would love to be a local in the factory watering hole and after a few beers and a few loose tongues, getting the real low down on the matter.
Indeed.
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Joyous news from San Diego! GP motorcycles just inspected my tappets and reported they are in perfect condition :thumb:
I have about 10k hard miles on my recall kit . Mostly canyon riding in Oregon and Washington. Perhaps there was only a bad batch of tappets that failed miserably right away?
Most of my riding was in a damp environment yet there is no milky colored oil in the valve cover. Maybe running it hard is the key to keeping moisture out of the oil? So happy, Thanks Santa :bike-037:
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Have you got pics?
Really John, I haven't inspected a single flat tappet bike since I started checking them all that didn't have damage. I'm really glad for you if yours are good but I really do think its a matter of when, not if.
Pete
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My mechanic thought MY tappets looked fine too, but after seeing photo's of them I had him submit them to Piaggio. They approved the roller tappet upgrade gratis (I paid labor).
If you can, post your pics of your tappets here or on Griso Ghetto; maybe the collective, with the collective experience; agrees with your mechanic. I push this because you want them replaced early in failure mode or risk punting the whole motor due to abrasive slurry pumped through it.
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Joyous news from San Diego! GP motorcycles just inspected my tappets and reported they are in perfect condition :thumb:
I have about 10k hard miles on my recall kit . Mostly canyon riding in Oregon and Washington. Perhaps there was only a bad batch of tappets that failed miserably right away?
Most of my riding was in a damp environment yet there is no milky colored oil in the valve cover. Maybe running it hard is the key to keeping moisture out of the oil? So happy, Thanks Santa :bike-037:
So if I am reading this right you are seeing good condition on the dlc coated flats installed on your early model 8V at its original cam issue recall. And at this point they have 10K on. If so good news. BUT if I were you I would keep a very close eye on them as the miles go by. By and large the dlc flats have failed anywhere from 3K to 50K. Mine were hosed at 16K with never seeing mayo or any other indication of trouble. I absolutely am not making any statement here and am only saying what in fact happened to me.
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I would seriously consider installing a roller kit NOW, don't wait until it starts to fail. You will have tremendous peace of mind knowing that not even an inkling of dlc is searching out your oil pumps and big ends. Do you have visual confirmation that there is no wear, or just the dealers word? I know it sounds like a pricey approach but actually it is rather cheap insurance . Dave
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sorry guys I'm going with the report the mechanic says. He's had the bike to completely apart before and fixed the clutch issues that nobody else could. I think GP will stand by me if there's a problem with the tappets in the near future..It's probably not as bad as we think. rumor mill says there's another one coming in there from LA for inspection also.
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I also have an 09 griso and my tappets were toast at 4000 miles. It also had the recall dlc tappets. I would have a talk with your dealer about exactly what they are going to do if and when the time comes . Will they cover the costs of inspecting the oil pump and flushing out the oil cooler? Also dropping the sump and inspecting the crank bearings? If they say no and you will have to pay out of pocket, I would just as soon spend it now on a preemptive solution. Most dealers I have talked to are only installing the roller kit, changing the oil and filter and sending them out the door. In any event catching this in the very early stages is essential.