Message text written by Fernando Sanchez Zinny
>Taking advantage of the list gurues's knowledge I would like to share with
you a recent situation with my oil pressure gauge. Instead of going up and
down smoothly, it started going up erraticly and never comes down, unless
you knock the instrument several times (same thing if you knock the brass
conecting pipe). Oil pressure seems to be OK. Any clue?
Again, many thanks, Fernando
<
Buenos diaz. I had a similar problem with my TR6 and this turned out to be
the gauge itself. The needle was bent a bit and was rubbing the gauge
face. It doesn't take much force at all to cause it to hang up like that.
The way the gauge works is there is a bourdon tube inside. That is a
curved tube. The pressure connection goes to this tube and under the
influence of pressure the tube tends to straighen out. One end of the tube
is fixe and the other has a linkage connected. This linkage is connected
to a tiny rack that turns a pinion gear that turns the needle of the gauge.
A very small piece of grit on the rack can also cause this problem.
But in my case the needle was dragging on the gauge face (probably due to
my own ham-fisted attempts to make it better). I re-fiddled with it last
fall and it now works freely.
These things are very fragile so if you attempt this be very carefull.
Good luck
Dave Massey
57 TR3 (and others)
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