Nice job, Tom however it was a disappointment not to see the first director's cut showing the oil spray. ;-)
I included that in an ABS modulator thread on another group at several points as: "Clean glasses as in step X".
I haven't gotten to lapping my relief valve as yet but seems like a no brainer if one is willing to spend the time.
Justjeff, given your professional exerience in this field, can you see any downside to lapping (improving the seal) of the relief valve?
It seems to me that It's unlikely that a small relief valve leakage will affect the operation under any but the most remote possibility so not likely likely to make any significant improvement. That said, no down side to if one feels like doing so....
Do you agree that this is an accurate view?
Tom, you commented regarding the bottom end being essentially like a two stroke and it certainly resembles those systems excepting for two factors which have been at the root of my concern from the outset:
1) The wrist pin does not have a bearing and runs directly in the steel of the connecting rod which means it requires both much more lubrication and cooling than a typical two stroke.
2) Piston cooling is highly dependent on oil spray from below onto the underside of the piston crown. None of us has been able to offer any means of evaluating the effects of reduced spray on piston cooling in this engine. IME, pistons reach a critical temperature after which they fail in a rapid progression.
Two cycles depend on the inlet charge for piston cooling which must be considered in design.
This has been a very interesting project and Paul has shown great courage in taking the risk of long distance trial.
There are many not qualified/not measured factors involved such as oil flow, for example. No one has been able to offer data or calculations indicating the effects of cross drilling the banjo bolts, for example. It is not unlikely that the cross drilling had no material increase in oil flow because the size of the cross hole may not be a materially affecting factor. That the cross hole is at 90 degrees to the axial bore will cause significant restriction, for example.
We don't have any indication as to the relative restriction offered by the long axial passage in the banjo bolt. It is quite possible that the longer axial passage has so much more resistance to flow that the cross hole size is immaterial. Someone pointed this out a while ago, again.
We have no indication as to whether the banjo bolt is a restriction factor at all, given the length of the oil pipe, so it may be that our drilling of the cross holes in the banjo bolt has no real effect on oil flow.
One would need to set up a test jig in order to attempt to duplicate the pressure drop across the various parts of the system as a means to evaluate these effects. If one has an oil temperature, same oil, and pressure at both ends, one should be able to calculate the oil flow rate, Correct, someone? Anyone?
Regardless of calculations, if one knows the pressure difference between the inlet and outlet of the oil pipe (for example) one could use the same oil at the same temperature with an adjustable oil flow to duplicate that pressure difference. Say, for example one had 5 PSI difference between the two ends, applying 5 PSI at the inlet should allow one to measure the oil flow rate. Knowing the oil flow rate/volume would allow one to experiment with changing the banjo hole size and so on to determine changes in oil flow.
I never did find a donor valve cover into which to glue windows to study oil throw-off from the cams and am into other interests but some time.
Too many unknowns and far to many assumptions here, IMO. We just don't know many of the things which are claimed.
What we do know is that Paul performed these several modifications, reported the data. We really don't know the import of the data other than we do know that Paul's bike made a long journey successfully, he reports improvement in oil consumption and fuel consumption which may not actually be due to the factors which we believe.
I'm convinced that the results and conclusions he reports are correct because they seem to be well documented and there is no doubt in my mind that he has reported accurately. When I state "accurately" I mean that he has professional competence to evaluate that the information reported is correct as reported. In other words, he has not made errors in terms of what he has done during the work. Very professionally done!
The apparent reduction in excessive oil throw-off, as I stated when first commented on this project, would be expected to have the results reported because we used to see these effects as common place in automotive engines when worn main bearings were encountered. We also saw oil consumption increase in engines which were fitted with a high pressure oil pump rather than a high volume pump. Both worn mains and higher pressure will/must increase throw off of oil onto the cylinder walls.
I am not convinced that the case has been made that cross drilling of the banjo bolts does increase (materially) the oil flow volume to either cams or transmission. As said, it seems like a no-down side as it may increase this flow which would seem not to be a bad thing. Paul's work is, I think, conclusive in showing that were flow to cams and transmission to be somewhat increased, this increase will not be likely to reduce the crankshaft oil flow to a problem degree.
Great stuff and much to think about however we do need to be careful in what conclusions we are willing to accept as proven.
Perhaps Justjeff may be willing to comment on flows and restriction effects?
Good on you, Paul. You do have a large set of coconuts for trying that long distance ride. I don't think I'd like to play chicken with you.
I'm certain that others also are very appreciative of the risk which you took in order to offer the outcome.