Ducati.ms - The Ultimate Ducati Forum banner

Rocker Arm Flaking

55K views 40 replies 21 participants last post by  ducatimike  
#1 ·
On bikes with 4-valve heads, the rocker arms have simply not been reliable. A good number of them flake-off their chrome plating before the time of their first service at 6,000 miles and that often can result in scratched camshaft lobes if not caught in time. The rocker arms in 851/888's and pre-1996 916's typically lasted 80K miles with no problems. 1996 was the year when Ducati began to outsource the rocker plating to subcontractors and problems began.

Ducati basically concedes that there has indeed been a rocker problem in the past, but has repeatedly assured us that things have been fixed. They also point out that the rocker problem will be covered under warranty, even if you're outside the warranty period, (if it's not a race bike or an SPS/R.) So, when you have this problem, just work with your local dealer who will replace the damaged parts. If you're out of warranty, you usually will have to pay for the labor cost only. Keep in mind, however, that the replacement has to be done by an authorized Ducati dealer in order for the cost of parts on an out-of warranty bike to be covered.

They're not just being good guys here. From a legal standpoint, if there is a known manufacturing defect, warranty period or not, the manufacturer is responsible to sell you goods that can perform up to the standard expected when purchased - no matter how long after purchase.

There probably have been 17 rocker design iterations over the years. For 2001, Ducati announced they were now using an improved rocker design that is also compatible with earlier year engines. The new 2001 opening rockers can be identified by a small dot punched on the side where they fit onto the shaft. Unfortunately these rockers fail in exactly the same way. So even if you have a 2001 or later model, make sure that when you have your bike serviced at 6K miles, that they remove the cams (25 minutes labor, you pay) and inspect the rockers since any damage cannot be seen otherwise. The flaking starts as small little patches and if you catch early you can avoid cam damage. Time your last major service before going out of warranty to make sure they’re checked, so your replacement labor charges will be covered.

To play it safe, and to make sure that Ducati doesn't balk at replacing your rockers, it's a good idea to keep adequate records to show that you've adjusting the engine valve clearances to Ducati specs on schedule, and used a lubricant that conforms to Ducati's specification in the owners manual.*There have been instances reported where some Ducati dealers have tried to make the owner feel that they have somehow abused the bike and then charged them for repairs.

The rocker arms have a hard chrome coating to increase their wear resistance where they contact the cam lobe. The opening rockers are more likely to be affected but occasionally the closing rockers flake as well. The closers don't take anywhere near the abuse as the openers.

There has been a lot of debate about the reasons why the chrome comes off. The answer is likely a combination of inadequate chrome thickness and the unusually long time needed for the oil to reach these parts during a cold start. In normal circumstances, a good synthetic oil would leave a surface film that is adequate lubrication until oil flow is established.

There's a correlation between a lack of oil and rocker failures. For example, the horizontal cylinder exhaust rockers sit in a oil bath and rarely fail. Most often, failures are seen in the more distant vertical cylinder rockers, especially on the hotter exhaust side. For the 1999 model year, Ducati increased the size of the oil gallerys to the heads to try to solve the problem.

There is a hope that the new testatretta engines with their plain bearing cams and having significantly shorter oil lines coming directly up the right hand side of the engine, would help reduce the 90 second-or-so lubrication delay encountered with the earlier engines. Time will tell.

I don't think Ducati knows the definitive answer. If they did, the problem would’ve been corrected years ago. If it's any consolation, this type of problem is not unique to Ducati. Other manufacturers have had rocker hard coating issues in the past. Honda, Kawasaki and Suzuki, to name a few.

Replacing a failed rocker with another having the same potential for failure doesn't make a lot of sense, so some owners have installed Megacycle rockers, stock rocker arms that have been machined down in thickness to allow for a greater thickness of chrome to be applied. Others say that the Corsa rockers are the ultimate fix, but others say no.

The Megacycle fix is to grind the rocker/cam contact area back .035 to .040 inches and then build back up with a hard nickle-chrome boron alloy brazed onto the rocker, then grind the repair back to factory specs.

http://www.megacyclecams.com/
 
#2 ·
2000 996

At the risk of pissing someone off: As I’ve stated before - in my case there is NO WAY even the best of chrome could stand up to the rotary file abuse - i.e. The Camshafts -All 4 in my case. Mine had such a course “Finish” (I use that word lightly) all they could do is grind the hell out of the rockers. Another Duc Drowns http://www.ducati.ms/forums/showthre...t=73773&page=3

DNA couldn’t blow me off fast enough about this issue, and IMO is trained in denial - at least that‘s all I‘ve ever got from them - needing to pummel answers out of them because they don‘t want to deal with you if they think it will cost them $.

“I don't think Ducati knows the definitive answer“. They know full well there’s more going on with this issue - how could they not? I think they know a thing or two about physics, but it boils down to $$$$$ - it costs money to actually fix the problem on thousands of bikes correctly, So they “Used to” (I was told by DNA they no longer honor this extended warranty) change the least expensive part (the rocker) - and only if the mechanic did actually do his/her job correctly. The dealers used to be paid in full by DNA for parts and labor - but they stopped doing that as I understand it, so for awhile there was an incentive for them to look closer.

Just throwing in more victims (rockers) won’t necessary do much unless the worn rocker smoothed the cam lobe finish out enough to lessen the damage to the new rocker - from what I’ve seen anyway. You’ll be faced with the continued problem if the cams are not polished. They cover the cams with a Moly (black) coating, but the surface under this coating is as you see in the attached photos. This is NOT chrome transfer - it IS the cam finish. Included is the same cam polished. The first 2 are rocker and matching cam lobe. They don’t quite match up if it were chrome transfer do they?

Not saying there wasn’t a problem with rockers. From my understanding the final step was not done (just like the cams didn’t get a finish grind/polish) as the chrome was not stress relived so it was brittle. That last operation cost money so they cut that step.

One of the worst rockers that failed on mine was the Horz. Head - Left Hand Exhaust Opener - one that is supposedly bathed in oil on start-up, so I don’t agree with that theory either. It was a Camshaft finish issue that pretty much took out all my opener rockers and was working hard on the closer rockers also - which I also replaced. The engine had just under 5K with what would have been the 5th oil change, by me, using Amsoil 20W-50 motorcycle oil starting at 230 miles indicated with the first flush oil change using Mobil1 15W-50. Doesn’t matter what oil you use if the cams look like mind “Did”!
 

Attachments

#3 · (Edited)
Rocker Flaking Early Warning?

There probably have been 17 rocker design iterations over the years. For 2001, Ducati announced they were now using an improved rocker design that is also compatible with earlier year engines. The new 2001 opening rockers can be identified by a small dot punched on the side where they fit onto the shaft. Unfortunately these rockers fail in exactly the same way. So even if you have a 2001 or later model, make sure that when you have your bike serviced at 6K miles, that they remove the cams (25 minutes labor, you pay) and inspect the rockers since any damage cannot be seen otherwise. The flaking starts as small little patches and if you catch early you can avoid cam damage. Time your last major service before going out of warranty to make sure they’re checked, so your replacement labor charges will be covered.
Bought my first Ducati in December 2012 (2001 748) so my exposure to the rocker flaking issue is new. I have read many of the forum's past threads and posts on this topic about the preventive recommendations and also the successful fixes/repairs, which are great.
My question is this: is there any performance indication that rockers are flaking that becomes evident before the bike is being serviced, valves adjusted, etc.? In other words, other than rocker wear followed by cam wear that is visible during service that might cause significant damage and expense if not repaired, is there a way to tell this is happening just based on some kind of noticeable change in engine performance?
My 748 has just under 3K miles on the clock. Don't know if that's a true reading, but if there's something I can do early to detect and address rocker issue, I might do it..
Thanks..hope this isn't the Department of Redundancy Department..
 
#4 ·
My question is this: is there any performance indication that rockers are flaking that becomes evident before the bike is being serviced, valves adjusted, etc.? In other words, other than rocker wear followed by cam wear that is visible during service that might cause significant damage and expense if not repaired, is there a way to tell this is happening just based on some kind of noticeable change in engine performance?
No, you won't detect a change in performance. Sometimes you'll find some chromium flakes caught by the filter screen. Have the cams pulled at the next service and have the rockers inspected for flaking chrome plating.
 
#9 ·
I am curious about the "rotary file" statement? I think if the chrome was applied correctly the cams would not be able to hurt the chrome regardless of the cams surface finish. That "hard chrome" has really high Rockwell numbers. Then again anything is possible; I am just ohere to learn!
 
#11 ·
Hi all. I know this is an established issue so sorry to those that have been over it before. I’ve read up on this more than once, but have been left with two nagging questions. The first question, which was answered above, was if you have the flaking rocker issue will you have a drop in performance, and the answer appears to be no so that you need to visually id the damage during inspection. The second question is , to me , the obvious corollary. If the flaking rockers don’t generate a drop in performance, then what is the downside. Are we talking about eventual rocker arm failure? Does the chrome circulating in the oil result in other engine problems? I haven’t seen this addressed in prior threads and would appreciate any input on what the end result of the rocker issue is. TIA.
 
#12 ·
Two metal surfaces sliding past each other generate heat and wear from friction. To minimize friction the two surfaces should be smooth, and to minimize wear these materials should be hard. Adding a lubricating oil to a smooth surface provides a thin film that separate the two metals, but if the surface is uneven the high spots will wear down.

Ducati rocker arms are plated with a hard material (chromium) and the camshaft lobes are hardened through heat treating — both are ground to a high degree of smoothness.

If you remove a portion of the rocker chrome plating, the softer metal underneath is exposed and the oil film cannot prevent contact between the cam and rocker chrome and base metal surfaces. The result is accelerated and uneven wear to the camshaft and rocker with the associated excessive heat and metal debris deposited in the lubricating oil.
 
#13 ·
but I'm using Agip synthetic, so I've got like a zero friction coefficient, right?:) jk. so, it sounds like cam damage and fragging the engine by recirculating the contaminated oil is the preeminent concern. from that standpoint, better safe than sorry makes sense. thanks.
 
#17 · (Edited)
There is more than a little truth in the joke about synthetic oil there incidentally.
I just stripped two 748s (wrote about it in another thread) one with 59k km on the clock.
One exhaust rocker had no chrome and as no flakes had come out of that engine for about 9k km and none was found inside when the cases were split I think it's safe to assume that rocker was running on the cam for that 9k km.
The cam has no measurable wear and the rocker is fine to re-plate, just the chrome gone and the undersurface was working just fine with the cam lobe.
The difference between the top of the existing chrome and the actual base metal of the rocker is 0.0015" which I believe is the thickness of the chrome.
This engine was run on full synthetics.

The second bit about recirculating the contaminated oil.. see my above posts, the main body of oil fed to the crank is filtered but not the portion going to the heads.
What were they thinking ?

davy
 

Attachments

#14 ·
One thing I have found whilst investigating the oil system on my 748/853 is that the oil supply to the rockers comes straight from the oil pump before the filter, in other word unfiltered oil is being fed to the heads, cams and rockers.
This the case on all machines whether or not an oil cooler is fitted.
Now that can't be a good thing.



davy
 
#15 ·
One thing I have found whilst investigating the oil system on my 748/853 is that the oil supply to the rockers comes straight from the oil pump before the filter, in other word unfiltered oil is being fed to the heads, cams and rockers.
This the case on all machines whether or not an oil cooler is fitted.
Now that can't be a good thing.
That's just Ducati's way of trying to get the chrome flakes back on the rockers where they belong.
 
  • Like
Reactions: Aguiar
#16 ·
Yes and the problem there is they are feeding it straight into the ends of the rocker shafts where it gets between the rocker shafts and rockers and also straight to the cam lobes.
I was thinking of fitting an oil cooler to the 853 but instead I'm working on a filter/cooler in the rocker feed line positioned in the airflow where a cooler normally sits.
That way I'm going to get slightly cooler, much cleaner oil to the heads


davy
 
#18 ·
Been involved with the whole rocker flaking phenomenon for last 10 yrs and have read countless theories as to the cause. I met a fellow a few years ago that has 40 years experience with the hard chrome process and has a company that chromes parts (parts used in landing gear assemblies) for the aerospace industry. Just to be able to provide parts for aerospace (commercial airliners) the company has to do business according to Mil Spec standards which requires the company to validate all its processes. I hold this gentlemen in high regard as he has actually developed many of the processes now used to make parts. He was made aware of the Ducati rocker issues and did a little investigation himself. Here is what he told me.

Hard chrome plating on the Ducati rocker arms, if done properly, should last for the life of the bike. Some of the theories talked about may contribute to a poorly plated rocker failing, but he told me that the main reason for a rocker to flake is that the base metal has not been prepared properly to accept the chrome. He told me that the base metal preparation was the most important step in the process, a step that his company developed many years ago and is still proprietary.

Here is the process he uses (from his website):
Our process includes stripping of the existing chrome, a stress relief bake, glass bead blast, polish, and a proprietary activation of the base material. Only then are the parts chrome plated to a specified thickness, achieving the maximum hardness of 68-72 Rockwell.

The fact that some Ducati rockers never flake tells me that the other theories (oil feed time, etc) are not the real problem. I believe Ducati sourced out the rockers to a vendor and apparently they did not get the process dialed in, hence the chrome flaked off during use.

Mike
 
#19 ·
I think you might be opening a can of worms here Mike, someone I know recently replaced a lot of rockers re-plated by a very reputable company in the US go bad on him in very short order.

I also repudiate the oil feed time myth as the rocker feed is before the filter and so gets full pressure even before the crank and oil pressure test port do
which are downstream of the filter.
My oil gauge line is the same dash 3 size as the rocker feed line and it gets pressure almost instantaneously on start-up and is longer than the rocker feed line.

davy
 
#20 ·
Davy if you put a filter in the line you would want to make sure it doesn't drain when the engine is off or it will delay the oil getting to the cams but i am sure you have thought of that.
 
#21 ·
HI Davy,
By reputable, do you mean a company that makes parts under a controlled process? There is a big difference. I would put faith in a company that makes parts for Commercial airliners. They use the same manufacturing controls that medical device manufacturers use. These controls assures that all the parts are made exactly the same and that there is no variation from batch to batch. They do this by validating the entire chroming process. They even come up with limits of variables like temperature, ion concentration, and time, etc., then monitor all these variables during the process. They keep records for each batch of parts and assign a lot number to each batch. So if a problem occurs down the road, they can go back to the records see all the details concerning the process for that batch of parts.

Some Ducati rockers arms last forever. Also, why do the rocker arms on a 95' 916 rarely fail, but the rocker arms on all the 96' through 2003 desmoquattro motors have a much higher incidence of rocker flaking? If the problem was something other than the rocker arms themselves, why would some last and some fail really early on? I think these facts points to process control issues during the hard chroming.

Another issue that has come up recently from a customer may also make a small contribution to the rocker flaking issue. A small percentage of the rocker arms are not ground flat. What I mean is the surface of the rocker arm should be parallel with the bore that the spindle goes through. A customer of mine measured and found a few of his rockers were not ground flat but at a small angle. What happens is that when the rocker is installed it contacts the cam on a very small patch on one side and not fully across the surface. This then puts higher contact stress on the rocker arm. I had him measure alot of rockers and it seems like it is only a small
percentage. So I dont think this is the cause of all the rocker issues, but may contribute in some small way. Also, I have seen many bad rockers and the worn contact patch is the entire width of the cam, which tells me the rocker surface is parallel to the surface of the cam.
Mike
 
#27 ·
HI Davy,


Some Ducati rockers arms last forever. Also, why do the rocker arms on a 95' 916 rarely fail, but the rocker arms on all the 96' through 2003 desmoquattro motors have a much higher incidence of rocker flaking?

from what I have read cagiva had better quality control on rockers
production moved in 95 96 and the plating had issue at new plant
 
#22 · (Edited)
Yes Mike I'm aware of the crooked rocker issue, the one faulty one I just removed from my old 59k km motor shows that symptom, the chrome is gone, the crater is tapered indicating face slope but interestingly the base material is working well and the cam is fine with no dimensional difference from it's twin.
If you re-read my first post you'll see at no point did I ever suggest that rocker flaking is caused by anything other than bad plating/preparation but I don't for one moment think that's the full story on these heads.
For instance why do I have two 748 engines with similar mileages but on one the rocker pin retaining plates have 34 thou deep scores from the pins but the other which has had very regular synthetic oil changes and good pressure the marks are only 3 thou deep?
This engine also when stripped and measured was found to be running clearances between 8 and 10 thou on all rockers, ran extremely hard and fast but was very kind to the valve gear, just that one exhaust opener which I believe had been like that for 12k km.
Perhaps running tight clearances on the gear isn't helping rocker chrome either as this one had done no damage to the surfaces inspite of the wide gaps contrary to popular wisdom.

davy
 

Attachments

#30 ·
Yes Mike I'm aware of the crooked rocker issue, the one faulty one I just removed from my old 59k km motor shows that symptom, the chrome is gone, the crater is tapered indicating face slope but interestingly the base material is working well and the cam is fine with no dimensional difference from it's twin.
If you re-read my first post you'll see at no point did I ever suggest that rocker flaking is caused by anything other than bad plating/preparation but I don't for one moment think that's the full story on these heads.
For instance why do I have two 748 engines with similar mileages but on one the rocker pin retaining plates have 34 thou deep scores from the pins but the other which has had very regular synthetic oil changes and good pressure the marks are only 3 thou deep?
This engine also when stripped and measured was found to be running clearances between 8 and 10 thou on all rockers, ran extremely hard and fast
but was very kind to the valve gear, just that one exhaust opener which I believe had been like that for 12k km.
Perhaps running tight clearances on the gear isn't helping rocker chrome either as this one had done no damage to the surfaces inspite of the wide gaps contrary to popular wisdom.

davy
The above condition is from oil pressure trapped behind the other end of the rocker pin! There's a fix for it. All do it to some extent some just more than others. Has nothing to do with rockers I would think!:confused:
 
#24 ·
HI Davy,
I agree there could be other issues that contribute to rockers failing, for example the one I mentioned. But I dont believe it is the main source of the problems. I say this because there are hundreds of rockers that have replaced bad ones that are not flaking. If the cause was something other than the faulty chrome process, why would not the refurbished rockers placed in the same valve always flake also? If they do I say the problem was never fixed. But not all of them have, so I still contend that a rocker that is plated properly wont flake.

Mike
 
#25 ·
I think we are on the same page Mike.
The rockers I pulled out of my donor 748 to 853 engine were in a really bad state so I didn't mess around I had all 16 of them re-chromed and re-profile ground so they are true by Wade Cams over here, but I still want to give them the best chance of survival long term hence the rocker feed line filter so I only feed them clean oil.

Davy
 
#26 · (Edited)
I have had my 02 748 for a couple years now..just hit 10K on the locks. I found out about this issue a month after owning the bike. Now that she has racked up a few miles, I have been watching it like a hawk. At the same time, I am learning no matter what, this is a expensive issue. That being said, I often think about selling it for something newer...but that is a shame since I really enjoy this bike.

Image

Image

Image

Here is my last oil change..I would also like to give the big middle finger to Photobucket and their new design...cant even sort by upload date.


..has anyone permanently solved this issue?
 
  • Like
Reactions: crashmctavish
#32 ·
With the amount of out of line between some rockers and the shaft axis I've seen which manifests as a one side contact between the cam and rocker as in that photo I showed I'd be very surprised if side thrust on the shafts isn't generated contributing greatly to end plate wear so I'm firmly of the opinion the rockers actually do have something to do with it.

davy
 
#34 · (Edited)
Well...it was my first time and I am not done..but what a pleasure to work on. I had to wait for some tools and some time..but I went in, and was left with some questions.

Image


Image

Well I only got the vertical cylinder done..I will do the horizontal tomorrow. But what do you think of the numbers?...I hope I am doing this right. Bike has 10K on the clocks. Seems everything was spot on.

Image

I noticed one of the pins wont go in all the way, it just pops back out .I believe their is air trapped behind it. Will it be ok or?

Image

The exhaust side..

Image

And here is the intake side.

Image

I went ahead and pulled the intake openers for pics, as they "looked" like they worst of the vertical side. There appear to be some slight discoloration to the contact areas , however it is smooth to the touch with the the finger and nail. You cant feel a difference from the rest of the surface. Are these acceptable ? And should I use any loctite anywhere?