barnett468
Coast to Coast
Sonreir said:
thats what i have commonly seen . . just to clarify, i was referring to cam and rocker damage vs cam bearing damage
Father Son 75 CB200T Rise From the Ruins
- Thread starter Texasstar
- Start date
thats what i have commonly seen . . just to clarify, i was referring to cam and rocker damage vs cam bearing damage
barnett468
Coast to Coast
DohcBikes said:
but he only ran it wot at 7000 rpm for an hour or so. :-\
barnett468
Coast to Coast
Sonreir said:I don't believe that's what led to the failure. That was several months prior to the problem. And it was more like 3/4 throttle.
Does that mean that you had done of few runs prior to that where you had maintained rpms above 6000?
Since the oil does cool the engine, and the faster an engine goes, the more friction is generated, thereby increasing its cooling requirements, its likely that had you sustained rpm of maybe 4000 instead of 7000 with your oil level, that the amount of oil you had would have been sufficient enough to keep the engine cool enough to prevent the failure.
In cases like this where there is no question that increasing the amount of oil to the top end will definitely help reduce the potential for failures, there is more than one way to reduce them . . In other words, if one does not increase the amount of oil to the top end, they can try other methods, and the simplest one is to use better oil . . If one is already using the best oil on the planet and failures are still experienced, cooling the oil would be an additional option . . If doing both of these don't work, one could try a thinner oil . . This would perform a similar function to modifying the system to increase the quantity of oil to the top end, HOWEVER, if the oil is the same brand that was being used, it will have LESS protective qualities, which means that increasing flow AND using a thinner oil is not necessarily the best option, but increasing flow and using the same viscosity and brand will help.
My point is that there is no substitute for high quality oil . . The weakest link in any chain will be the first one to break, and you can have a gallon of oil per minute flooding the top end, but if the oil is not good enough for the app, there will still be failures.
I understand people not knowing which oils are better than others, but I don't understand the people that know which ones are better yet still buy the lower priced ones for an expensive machine or even for any machine for that matter . . I'm not suggesting that this is what you did, I am only mentioning it as a general thought.
imo, it's a bit like people that buy Chinese parts for their car and then cry when they break . . Well, either quit your $5.00 job at Mcdonalds and get better one so you can afford better parts. or if you have enough money and buy Chinese parts and they break...don't cry and look for sympathy when they do.
As far as the reason that a rocker arm will fail before a cam lobe does is simple . . The amount of force applied to both is exactly equal and is applied to the same amount of area at the point of contact, however, because the cam rotates and the rocker does not, the area on the cam keeps moving so the pressure is not applied to the same spot for nearly as long.
It would be similar to dragging the rocker along the road as you drive . . You can see that the rocker and road receive the same amount of force but the road is no longer in the same spot as it was when you started but the rocker is still in your hand . . This is basically the premise upon which the Timken wear test operates, which is the same premise that all grinding wheels operate, but in this instance, an abrasive is added to the wheel to speed up the "wear" process.
Once the rocker face is worn, it will more easily damage the cam lobe and the rate of cam wear will increase . . Another way to reduce rocker wear is to have them hard welded, however, this is still not a substitute for high quality oil or increasing the amount of oil to the top end and really is only necessary for high perf apps.
barnett468 said:
Regularly and frequently. My ride to work was about 20 miles of highway.
For what it's worth, I'll admit it's possible that a higher quality oil may have saved me some heart ache, but actually having the correct amount of oil in the cases would be a lot better option, supposing you had to pick between the two.
barnett468
Coast to Coast
Sonreir said:
LOL, I KNEW this was going to turn into an oil thread and right now DOHC is laughing his back side off . . [I made that comment PG for the sake of Texasstar's son.]
As DOHC knows, more info would be needed for a half way intelligent "guess" could be made, and imo, the most important things to know are the following:
What is the recommended oil capacity of the bike?
How many miles were on that oil?
Exactly who mfg'd the oil for NAPA?
What was the API rating of the oil?
Knowing the mileage on the oil and the type of abuse [use] it incurred is important because the engine reduces the additive package as the mileage increases which reduces the oils anti wear capabilities and also increases its acidity . . If it was a grade I, II, or III oil, it can also, and often does, "shear" the tiny molecules that are added to make it a multi viscosity oil, and the more of these molecules that get sheared, the LOWER the viscosity will be, and in fact, it is possible for an oils viscosity to be reduced by 1 full viscosity . . I have seen this happen on numerous occasions, and this shearing is more common than some realize, and obviously, if the mfg recommends 15w-40, and the oil shears causing it to break down to 5w-30, it definitely isn't a good thing, AND, if one adds the lower viscosity to reduced levels of ZDDP and/or other anti wear agents, it is an even worse thing.
Anyway, based on the info you have supplied, I think that using the lower oil level with a very high quality oil would have prevented the problem, however, since you said that you had made many similar runs before with the higher oil level and it didn't seize, obviously running the correct level with the same oil you had run it with many times before would be the safest option because there is no guesswork involved . . That being said, if you had been running good oil all along and then you had just put in crummy oil, if an oil level that is less than the mfg is used, I would definitely use a higher quality oil than the NAPA is.
As you can see by this, things aren't always cut and dried, and proper controlled testing that yields repeatable results is really a very time consuming and detailed process and is actually one of the things I did at Kawasaki.
