Subject: Re: Oil Pressure Warning Light
Author: Patrick Hayes
Date: Feb 22, 2005, 12:48 PM
Post ID: 1718436231
Robert Hawkes wrote:
| Patrick, are motorcycle oil pressure switches generic or specific to each brand of motorcycle? Thanks BOb |
Not quite that specific. There are some variations for the set low
pressure which triggers the light and also for the max pressure
tolerance of the switch itself. The Guzzi motor would likely be at the
lower end of either of these variations. Another important concern is
the threaded lug. They are not straight drilled and threaded holes, but
pipe tapers which seal by thread compression. American car switches
would use a tapered standard pipe thread pitch and taper angle. Euro
switches might use some euro pipe thread. (Oddly, the whole world uses
fractional inch measurements for standard ball bearing diameters.) I DO
NOT know if they are the same. It is entirely possible or so close as to
not really matter. Otherwise almost all switches will ground out at
about 5psi or so. Easy enough to pull a switch and go to any napa store
for thread comparison. I used to have a "T" fitting on my eldo with
both a Buick pressure switch and a SW gauge. My cold start oil pressure
(100K crank and bearings) would be 65psi. Once it heated up it ran all
day at 54psi. In extreme desert heat it might drop to 45psi and then
I'd slow down. Idle pressure was usually about 8 psi or so when hot and
the light would trigger at about 6psi. I ran an old VW for years which
idles at about 4psi and NEVER saw 40.
Patrick Hayes
Fremont CA