Originally posted by Canniboomer Question, if we stop and lay our rigs on their sides every 20 minutes, would that assure some "bathing" of oil to the crank and wristpin?
:confused:
This should not be neccesary.
"Hey George, why does the Cannondale team all have their bikes tipped over in the mud?"
not to mention there really is not much oil in the crankcase, so saturation is unlikely... Remember, it is a dry sump system. Most oil remains in the frame spars.
ok ill say this this is over my head. but like sume said here most of the oil is in the fram right. could the oil pump bypast the fram back to the motor maybe like sume oil tank sume thing like a 400ex?????
Wolfman never thought of that one.We actually do have about 1/2 a quart in the sump at all times unless there is a pump failure.Even if we had more the problem would be getting the oil to the rodbearing. A good example of how complicated this is Local Racer had his motor stall and lock up for a second.We were concerned but thought it must be some fluke thing since it started right back up.He ran two flat track motos and two mx motos that day along with more practice.Ran perfect and even placed real well. This was around the time when bolts were falling out quite frequently.Anyway he sold the thing and wanted to check over the motor before shipping it out.First thing I did was drain oil.Only a trickle came out of motor drain.Pulled motor and sidecover.8 bolts fell on ground.Not good!Completely took motor apart the counterbalancer shaft which drives the main oil pump was sheared and not doing a thing!This was caused by the crankplate floating around.The right intake and left exhaust cams were washed out big time.Piston pin was scored slightly along with some scoring in cylinder. That is ALL!!The crank was fine (03 stock crank)and it was run without any real oil pressure for God knows how long.Some must have gotten to it but it wasnt much.Now that was only one case.The vast majority of other motors I have seen the rod bearing is shot(tight) or showing some wear or heat marks But why was that crank able to survive on almost no oil? Speaking of the main oilpump (one with filter on it)we are all concerned when the checkball sticks causing hydrolock at startup but what if it sticks closed?There would be no oil getting to motor at all. The possibilities are endless for such a problem as ours it is not a simple matter.Think about it Cannondale had all kinds of resources when they designed this motor yet the cranks were a major problem yet as Jay said his and others were fine.It could be that at the level we are now at with 4st motors a certain % of failures because of defects is unavoidable in mass production.But now we arent talking mass production so the rate should go down and not up.
Another good theory could be that the pin is distorting under the extraordinary force needed to assemble crank.This would explain why some stockers fail and some dont and would also explain why Winks seem to fail at a higher rate than stock since the odds of distortion would probably be increased with the extra oil holes that supposedly were added to the crank pin.There is no way to check for distortion or even cracks once it is put together other than feel or maybe a xray of some sort.Just guessing here though since we dont really have any good numbers to confirm any of this.
..This is kinda OT but has anyone ever heard of a ristpin breaking?....and no not keepers comeing out,not droping a valve..just breaking right down the middle..
Just fillling the case with oil like an oil bath would do nothing for the rod bearing. The purpose of oil pressure is to force oil into the voids between two moving surfaces to a point where there is actually no metal touching metal. The two parts would then hardly ever wear out. On our air boats, we have to run old and wore out cranks and rods and pistons because we cannot afford to buy the new stuff (eg. one cylinder with piston $1685.00...times six). Our oil pressures often leak down to about 10 psi at 2900 rpm. I know that this is slow, but these are stroker motors and torque monsters and thats not the point. My point is that, these bearing failures must be due to no oil getting to the rod bearing itself. Even if it had 10 psi, I believe it would run fine. All the oil, however it gets to the rod bearing, must be leaking by it somehow. At that same time, there are a bunch of them out there that have no problems at all.
What about making it a wet sump system while devoting the oil pump to oiling the rod bearings? I'm just throwing absurd ideas out there- if we ever see an XR reliability I can die a happy man.
Originally posted by Bags Just fillling the case with oil like an oil bath would do nothing for the rod bearing. The purpose of oil pressure is to force oil into the voids between two moving surfaces to a point where there is actually no metal touching metal. The two parts would then hardly ever wear out. On our air boats, we have to run old and wore out cranks and rods and pistons because we cannot afford to buy the new stuff (eg. one cylinder with piston $1685.00...times six). Our oil pressures often leak down to about 10 psi at 2900 rpm. I know that this is slow, but these are stroker motors and torque monsters and thats not the point. My point is that, these bearing failures must be due to no oil getting to the rod bearing itself. Even if it had 10 psi, I believe it would run fine. All the oil, however it gets to the rod bearing, must be leaking by it somehow. At that same time, there are a bunch of them out there that have no problems at all.
Then perhaps a system that utilizes the existing oil pump with an oil bath lubricating the crank main bearings, and maybe the oil pump outlets plugged and tapped to direct oil over the wristpin and connecting rod bearings, and anything else the oil bath doesn't coat (Maybe even tap the transmission pump to supply the head with oil????). It worked for the XR's.
XR reliability... heck, even 400ex reliability will not be achieved.. bummer huh?? Thats the tradeoff I suppose. Personally I would like to see at least 200hrs on a motor before a major rebuild being needed. I believe that is achievable if we dont give up
