Date: Sun, 21 Jun 1998 01:16:02 +1200 (GMT)
From: Alan Lewer
Greetings fellow Norton lovers, as a change from slurs and spelling ;> here's an article I wrote for the NOC New Zealand, hope you find it interesting.
Norton Commando 850 mark 3 - oil temperature
or good oil on keeping the oil good!
Some time ago I fitted an oil pressure gauge. This provided something else to look at whilst bombing along, and judging by the way the pressure fell off whilst maintaining the legal limit it provided information to do with the way viscosity varies with temperature for various oils. Not entirely scientific perhaps, but a reasonable basis for comparison. The gauge showed 40psi at 70 mph after 20 miles or so from cold, and after that, if the speed was maintained, dropped variously depending on the oil used.
GTX 15/50 fell to 32, which was the biggest drop of any of the oils I used: GTX2, Shell Helix, Penzoil 20/50, Penrite 25/50 showed lesser drop, in that order.
So I fitted a thermocouple sender temperature indicator (i.e. pretty
accurate), with the thermocouple about 1 inch below the oil level in the
oil tank, which after a number of journeys told me:
at constant 65 mph, 95 deg C
at constant 70 mph, 100 deg C
good belt, 120 deg C (on private roads of course)
around town, 95 deg C
when the air temperature was around 20 deg C.
I asked the oil companies what happened to multigrades at 120 deg C plus(given that the oil returned to the tank is a mixture of cooler oil from sump and hotter oil from head) and got no clear reply...and also what temperature oil should be run at. This produced the info that the oil temperature in a car sump is, desirably, around 85 deg C.
So this made me decide to put an oil cooler in, and an oil thermostat,
which resulted in:
at constant 65 mph, 80 deg C
at constant 70 mph, 85 deg C
good belt, 100 deg C
The pressure gauge showed 38 psi without cooler, 42 with at 70 on
25/50 Penrite and 20/50 Penzoil (which I use mostly) oils.
I bought the Hyde oil cooler, which is quite trick, but doubtless the local Japscrap shop will provide a cheaper one. Don't skimp on the oil lines - eggs fry well at the temperature the oil reaches - get proper oil line hose which is marked with the purpose.
I bought the thermostat from Tony Hayward in UK, and its a bit of a tight fit but just goes in above the gearbox, to which position the pipe runs are reasonable. One pipe required a metal right angle bend.
And to round it all off, I fitted a car accessory temperature gauge on a nice stainless panel (great, something else to polish!) that a mate made for me (thanks Micky). This moved the front of the Mark 3 binnacle forward to more or less in line with the instruments, so it looks good and makes the gold Ulysses badge more prominent, as of course it should be.
Alan Lewer
P.S. Ulysses Club is for motorcyclists over 40 in Aussie and New
Zealand,
gold badge is for the geriatrics over 50!