I am prepping for my motor build but noticed something yesterday that made me wonder
Is the oil pump drive shaft - driven by the crank really just running in the crankcase depending on oil to prevent wear or seizure - no bush or bearing used
That's how it is John...It works fine, I've yet to see a worn out one...
On the same subject a word of caution. Don't fit a Draganfly drive shaft without taking extreme care to ensure it is correct...They are made in India and the gear is incorrectly machined resulting in all sorts of problems with the crank pinion ...I have had personal experience of this on 3 occasions...
I'm unsure whether Draganfly have corrected the problem...Ian
I have a Draganfly drive shaft that has been sitting on a shelf for a few years after hearing about the possible dodgy nature of these and not being sure if it was OK or not. How can I tell if it is a good ‘un or not? It looks much the same as the old ones I have, except the teeth are not worn out.
Once I'd established on the first occasion that the shaft was at fault I didn't bother to go into specifically what was wrong with it...It's either the tooth form or the tooth angle/depth or a combination of those features...
If the crank is in the engine with the crank pinion fitted you will find it hard, or impossible, to fit the drive shaft due to the meshing problem between the two gears...
Don't be tempted to apply any force...That will probably lead to broken teeth which can make it difficult to extract the (now jammed) drive shaft without damaging the housing that it runs in...Also the crankshaft pinion may sustain some damage...
If you can't feed the drive shaft in by hand without excessive force it's may be a dodgy one...
It's worth remembering that the reason most pump drives are worn is as a result of a tight oil pump. It should be possible to turn the oil pump by hand using the oil pump drive shaft when these parts are fitted to the crank cases (before the crank is fitted)... I do this first and then remove the parts again prior to general assembly...
If the pump is too tight that problem needs to be addressed or the new drive shaft will soon wear....Ian
