EGT gauge

[Tom Endy]

Does anyone have experience running a Model A engine in a test stand equipped with a tachometer and an EGT gauge? I would like to know what kind of temperature readings are observed at different RPM's, and at different GAV settings. Also where exactly is the EGT probe inserted into the exhaust.

Tom Endy

[Phred]

Slightly off topic...

When I got my first Model A about 10 years ago, I installed a Westach 2C2-1 EGT gauge in hopes of monitoring GAV setting and/or ignition timing efficiencies. Never did see much change on the gauge with different settings.

I had the probe installed approx. 2 - 4" below the exhaust pipe/manifold joint.

Peace

[d.j. moordigian]

Originally Posted by Tom Endy

Does anyone have experience running a Model A engine in a test stand equipped with a tachometer and an EGT gauge? I would like to know what kind of temperature readings are observed at different RPM's, and at different GAV settings. Also where exactly is the EGT probe inserted into the exhaust.

Tom Endy

The engines we ran on the dyno's had the probes as close to the
exhaust ports as possible. The aircraft pyrometer ports on the
exhaust headers are about 2" from the flange. The farther away
from the port, the less you know about the true temperature..

Tom,...what I'm saying is....use 4 probes / meters and put them as close
to the block as possible.

[SAJ]

Hello Tom,
I fitted an EGT gauge to my roadster after I burned No. 3 inlet valve. I suspected lean running and wanted to see what effect mixture and spark timing had on the temperatures. Attached are pics showing the thermocouple which is in the top of the manifold next to the no. 3 exhaust valve. The unit is powered by a 9 volt lithium battery, because I could not find a 6 V unit. It has an on-off push switch for intermittent use since it was intended to be only temporary while I found out what was going on. The switch is mounted to the late-type steering mount I fitted to the car.
I get maximum 720 deg F when running up a long hill at 57 MPH in 3rd gear (the fastest it will go up this hill). Normal running at 60 MPH on flat motorway in overdrive (Mitchell) is about 580 to 620 Deg F. Idling is about 400 Deg F. fully retarded. Car runs a water temp of 145 Deg with a 160 deg thermostat in the top hose.. I checked the thermostat and it opens at 160 deg, so I don't know why the motor runs so cool. Temps checked with an IR thermometer, but I cannot check the thermocouple accuracy in the EGT meter, though it is a new good quality Dragon brand stepper motor type, according to the box it came in.
I have more exact figures elsewhere if important. But what I can say is altering the GAV from fairly lean to over-rich does not affect the temperature on the gauge, even climbing long hills at high revs. in 3rd. This did surprise me.
But retarding the spark makes the temperature climb quickly to dangerous levels when running, but not so badly at idle where full retard seems quite happy.
Engine is 120 thou over, 5.5 head, 330 Stipe cam, standard muffler, 95 psi compressions, B carb and bored manifold.
I now think my burnt valves started when the engine nipped up after an "expert" I asked to check my diff. when I was too busy to do it myself, instead re-tuned the engine and sent me home down the motorway with a severely retarded ignition. When I got off the motorway it stalled and would not turn over on starter or crank until it cooled. There seemed to be no damage but I surmise this warped a valve head, and started the valve burning episode.
The real cause of the jerky running was a bent diff carrier and Crown gear wobbling .040. I rebuilt it following your instructions which were invaluable!
I don't let anyone else work on my car now. There are too many "experts" around.
SAJ in NZ

[Bill in SoCal]

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For those that wonder - like me, Exhaust Gas Temperature (EGT).