Tornado
VIP MEMBER
- Joined
- Dec 5, 2017
- Messages
- 4,863
After reading this excerpt from a doc found on NOC (attached below), i've decided to follow the sage advice and eliminate a possible engine killing liabilty:
"Mention of pressure brings me to another point-the fitting of oil pressure gauges. On the Commando (and for similar
reasons. most bikes) an oil pressure gauge is more of a liability than an asset. It is of necessity, fitted on the feed side
where any failure of pipe or gauge is disastrous to engine and rider--it's touch and go whether the engine seizes
before or after you fall off with oil on the back wheel. On the Commando this failure could be caused by engine
vibration in the same way that early rocker pipes failed. (We're coming to that.) The other reason that a pressure
gauge isn't much good is really twofold. At high speeds and high oil temperatures the pressure can drop to nothing
on the gauge because the pump can hardly keep up with the rate the stuff is flying out of the big ends. The
centrifugal force can keep the pressure at the big ends above the danger point, so there's no real panic--but the gauge
would inspire you with horror. Then of course if you did seize an oil pump by the time you noticed that the pressure
had dropped the big ends would have gone (. . . through the hole in the crankcase, with average N.O.C. luck!). If you
want an interesting gauge to frighten yourself with, but, which is inherently safer and can give useful information, fit
an oil temperature gauge in the oil tank. Let me know what it reads as you change into top for the Mountain Mile on
both the fourth or fifth lap! The latest Racing Nortons (we can't call them J.P. Nortons any more as they've stopped
the bikes from smoking) had a new type of oil pump-I wonder if this is because the ordinary pump can't keep up?"
"Mention of pressure brings me to another point-the fitting of oil pressure gauges. On the Commando (and for similar
reasons. most bikes) an oil pressure gauge is more of a liability than an asset. It is of necessity, fitted on the feed side
where any failure of pipe or gauge is disastrous to engine and rider--it's touch and go whether the engine seizes
before or after you fall off with oil on the back wheel. On the Commando this failure could be caused by engine
vibration in the same way that early rocker pipes failed. (We're coming to that.) The other reason that a pressure
gauge isn't much good is really twofold. At high speeds and high oil temperatures the pressure can drop to nothing
on the gauge because the pump can hardly keep up with the rate the stuff is flying out of the big ends. The
centrifugal force can keep the pressure at the big ends above the danger point, so there's no real panic--but the gauge
would inspire you with horror. Then of course if you did seize an oil pump by the time you noticed that the pressure
had dropped the big ends would have gone (. . . through the hole in the crankcase, with average N.O.C. luck!). If you
want an interesting gauge to frighten yourself with, but, which is inherently safer and can give useful information, fit
an oil temperature gauge in the oil tank. Let me know what it reads as you change into top for the Mountain Mile on
both the fourth or fifth lap! The latest Racing Nortons (we can't call them J.P. Nortons any more as they've stopped
the bikes from smoking) had a new type of oil pump-I wonder if this is because the ordinary pump can't keep up?"
