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 Old Hutcho
Officially Full-On Dubber
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Location: Bomaderry NSW. 2541
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| posted on February 15th, 2006 at 07:27 PM |
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Voltage affecting gauge accuracy???
OK boys and girls. Here is the scenario. I built a 1916 with 8.4 to 1 comp. Engle 110 cam, twin 40mm dellortos. Bandido 043 heads, stock crank.
Car runs sweet as. Changed the main jets down from 140 to 130 on Sunday and drove it home. The temp gauge didint read any hotter than with the
140's.
But it runs hot. Bloody hot. Or so the gauge says. I drive it and the gauge says 100 degrees celsius. Thats hot. I stop the car, let the needle
fall back and switch it back on and the highest it reads is 90 degrees.
I reckon the gauge and sender are OK. Trust me.
One of the gurus here has said that perhaps the gauge is reading high because I now run an alternator (converted it from a generator) and the system
is taking relatively high voltage. Maybe up to 13 or 14 volts.
Will high voltage cause the gauge to read high? Or is my guru pulling my chain.?
Old Hutcho
ps. Isnt it great to see Wendell Sailor and Lote Tuqiri playing their hearts out for NSW. Thats pride for you.
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modulus
A.k.a.: Peter Hill
Veteran Volks Folk
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| posted on February 15th, 2006 at 08:42 PM |
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Possibly.
The temperature senders work by changing the resistance of the sender as temperature varies, and the gauge works by displaying (effectively) the
voltage drop across that resistance. So, if your battery is flattish or dying and your regulator is set normally to about 13.8 V (thats the proper
voltage in a nominal 12 V system), you indeed get a difference between engine on/engine off. Could also happen with an OK battery but Voltage
regulator set overly high.
You can:
- check that your regulator is set correctly and that your battery is healthy and by appropriate adjustment get the engine running / not running
readings aligned or
- live with it. The reading is not particularly important (it is, after all, only the oil temperature at one particular point), but variations are
important i.e. when it climbs to 115 on a hot day then you might want to back off.
I think your guru may be the real thing.
hth
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Purple Martin
A.k.a.: Martin
Fahrvergnugen
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| posted on February 16th, 2006 at 01:16 PM |
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Many car dashboards have a voltage regulator in them to deliver a steady accurate 10V to the guages, otherwise the guages would read differently under
different battery and driving conditions. Our after-market guages on our VWs don't have a regulated power supply and so they do vary a bit. The
trick is to get used to what is normal guage behaviour for your car and then watch for readings that are unusual. As for how hot your motor is
running... if you can hold the top end of the dipstick comfortably, the motor is not overheated.
1959 red & white Beetle
1975 Kombi camper
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lugnuts
A.k.a.: Mike
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| posted on February 18th, 2006 at 05:43 PM |
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What idle jets are u running,your still on your idle jets till 2500-3000rpm.
[ Edited on 18-2-2006 by lugnuts ]
Dont listen to what they say,just watch what they do.Oh yeah ive NEVER finished anything ive started.:o
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Old Hutcho
Officially Full-On Dubber
Posts: 281
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| posted on February 18th, 2006 at 07:07 PM |
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Lugnuts
I am running 60 idles, and now 125 mains
Old Hutcho
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lugnuts
A.k.a.: Mike
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| posted on February 18th, 2006 at 07:19 PM |
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I know u said the sensor and gauge are fine but if u get some spare time :P u could try the sensor with gauge attached in boiling water to
verify,preferably still attached to car and engine running.
Dont listen to what they say,just watch what they do.Oh yeah ive NEVER finished anything ive started.:o
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 Bizarre
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The artist formerly known as blue74l
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| posted on February 18th, 2006 at 08:07 PM |
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how long does it take to read 100???
Under what conditions???
cruising round town or a hr blast along the Princes??
Futue te ipsum!!!
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