Steve and All,
Yes, from my experience, your temp probe IS accurate and your gauge is NOT.
Frankly, this is something I caution all Tiger owners about....to make sure
the gauge is reading accurately. In my case years ago, the culprit was the
temp sending unit.
If I recall correctly, I think it was Stu Brennan (please listers, if I am
wrong, correct me, so credit is given where it is due,) who did some nice
work regarding ohms put out by the sending unit in relation to actual
temperature. This is a good table to help you judge weather it is a bad
sender or gauge. Chances are it is the gauge.
Unfortunately, I cannot recall WHERE this fine work resides no, but I seem
to recall that it is on the TA/AE website or Mark Olsen's site.
OK, there I go....lotta help....provide an enticing portion of the solution,
but not where to find it!
Regards,
Allan
-----Original Message-----
From: owner-tigers@autox.team.net [mailto:owner-tigers@autox.team.net]On
Behalf Of SJC Worldwide
Sent: Tuesday, April 24, 2001 7:16 PM
To: Tiger Mailing List
Subject: It Looks Like It's Really Hot??!!!??
Hello Sunbeamers:
I'm getting ready to complete my air conditioning installation in the
Tiger in the next two or three weeks. It took a long time to figure out
a setup that will work and, inside the passenger compartment, look like
the factory did the installation. It's a long story and I'll post
pertinent details after the job is done for those interested. I will say
I have spent waaay too much time at auto junkyards lately (Pick Your
Part especially) looking at different A/C setups before I found
something that I think will get the interior cold, not overheat the
engine, and look pretty "cool" inside too. I felt reasonably guilty
ripping apart a few older cars' dashboards to get what was behind them.
The wreckers said no problem, though.
Speaking of keeping the car itself reasonably cool, I am suspicious that
my water temp. guage reads much higher than the water temp. actually is.
I bought a GB digital multi-tester today with a temperature probe. The
probe is a metal tube and temperature of the object is determined by
touching the probe to it and waiting a few seconds. Just to make sure
the tester itself was accurate I boiled a pan of water and tested it
and, sure enough, the reading was between 210-212 degrees.
I warmed up the Tiger and, touching the intake maifold right next to the
factory temp. sender with the probe, here's what I found, comparing the
probe readings with the in dash Jaeger guage. The probe gives an exact,
digital readout and, as we know, the readings on the dash guage are
guesstimates relating to how close the needle is to the numbers on the
guage face. The numbers were: 190 degrees (probe)=225 on the guage
(approx).......180=205......188=215-220..........
179 (probe)= 210 (guage)..........175=205......177=210...... and
180=210. Taking the spread between the probe and the guage, this
averages slightly over a 30 degree difference. The Tiger behaves, by the
way, like it is running at the lower temps. as, even stuck in stopped
traffic today (90++ degrees) when the guage reads up to 230/240, the car
runs fine and doesn't ping when you "nail" it. Also, no loss of coolant
(other than some recycling back and forth from the header tank and my
extra overflow tank), and as soon as I get moving the temp. comes back
down to 200-210 (on the guage).
So, if the probe is accurate (and it's reading temperatures on the top
surface of the manifold while the guage is reading the water inside), I
need to re-calibrate my temp guage 30 degrees cooler, which I'll be very
happy to do. I'd appreciate the opinions of the group.
Steve Sage
1967 Tiger MK1A (289)
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