- Thu Jul 12, 2012 10:38 pm
#14722
Hi Leon. I used to think that oil pressure gauges or warning lights fitted to engines with plain bearings were superfluous in that if one suffered an oil delivery or pressure failure the engine would be wrecked within seconds of it happening. In fact I had an old Velo LE that I used to run around on a dirt track. One day I knocked a hole through the external oil pipe it had but I wanted to get it home. Within less than 5 seconds the engine had seized solid. However with an engine with all ball and roller bearings there is a chance that with a warning you could shut down the motor quickly enough to save it without hardly any damage to the bottom end, there might be some scuffing of the piston surface but at least the warning saved some great expense which is definitely worth having. Experiments were tried at one time where an engine had the oil supply to the crankshaft diverted past the oil pump and the centrifugal force of the big end spun enough oil out of them to lubricate the big ends just as well as having the pump working. Of course this could only work when the engine was revving highly. Unfortunately if the Bullet pump when not working (oil spindle stripped) the piston pump would block the oil flow instantly and the plain bush (floating) big end would be wrecked or severely damaged. Even an oil pressure gauge is probably not that useful if you think about it. We would know the recommended oil pressure but what would you do if the oil pressure was low? It would not seize and the engine would carry on as before until the big ends became too rattly, which is why the oil pressure was low in the first place. The low pressure would not mean that the engine was short of oil circulating, so the rest of the engine would be getting plenty of lubrication perhaps even more than when the oil pressure reading was high as a high pressure usually is blowing oil off through the relief valve. (I know Indian Bullets mostly don’t have one) So even with low oil pressure you might as well continue to use the bike until the big ends completely wore out. So all in all it’s hard to see the value of warning systems, perhaps ignorance is bliss, or does a stitch in time save nine? On balance if it gives the rider some relaxation and a feeling of confidence that all is well down below, maybe that is a thing worth having especially or perhaps only if the warning it gave was so clear and obvious that an instant engine shut off could be done. Perhaps wiring it into the ignition system to shut off the engine automatically would be best, but it would need bypassing to start the thing...Oh well…Nighty night.
