Is there any chance that the original gauge is designed to be accurate with
the engine oil warm? This would explain your observation that the tube was
"stiff". However, I can't imagine that much warmth could be transmitted down
the plastic pipe to the guage even if it had leaked to the point of having
oil all the way throught the pipe.
I converted to an electric gauge (el cheapo) due to hatred of the ever
leaking capillary tube. Now to get the look right I am examining replacing
with a Smiths electric I see is on the site of that company repairing and
selling their gauges.
Mark Hooper
-----Original Message-----
From: Hugh Fader
To: '6pack'; 'triumphs'
Sent: 21/01/03 5:54 PM
Subject: Oil Pressure Gage Calibration Check
I recently put my early TR6 oil pressure gage on a NIST-traceable
pressure
calibrator. I checked the actual pressure required to get the gage to
read 2
kg/cm2, 50 PSI, and 5 kg/cm2. The calibration is way off! Here is what I
found:
Gage Reading Calibrator
PSI (kg/m2) PSI
28 (2) 33
50 (3.5) 62
71 (5) 90
I remember someone on the list saying that the readings went higher as
the
gage aged -- possibly because the tube inside became fatigued and easier
to
move. Doesn't look like that's the case with mine. Maybe the tube
actually
becomes work hardened and harder to move or maybe things get gummed up
and
there's higher friction.
My hot oil pressure at 2000-3000 RPM was dipping below 50 PSI as
indicated
by the gage and I was a bit worried because I just rebuilt the engine. I
guess it was really reading 60!
Anyway, keep this in mind next time there's a "Mine's bigger than yours"
discussion about oil pressure.
Regards,
Hugh Fader
|