It is critical that the EGT probes be placed the proper distance from the
exhaust valve - otherwise the temperature readings will be meaningless.
Gasses will be much too cold at the collector. The general rule of thumb
I've seen is roughly 4-6" from the exhaust valve opening. That's where I've
placed the EGT's on my 1600 race car. I'm using cylinders 1 and 4 for my
measurements, but to really know which ones are the leanest, you would need
to measure all four collectors.
I must add that it's been one of the most helpful tools I've had in the race
car. It is great for checking carb mixture balance.
Expect to see temps between 1350-1450 degrees F when everything is good. As
you start to go lean, the temps will skyrocket. At 1600 you're about ready
to burn a hole in a piston. If you go rich, the temps will cool off.
However, there's a crossover point at which temps will begin to cool off if
you go way, way too lean. In my experience, you'll feel the drop off in
power before this happens, though.
Also, the engine must be under load for the temps to make any sense.
Regards,
--
Chris Coker
69 1600 SPL311 <http://mywebpages.comcast.net/chriscoker/roadster.html>
66 1600 GP Race Car www.risensonracing.com
Royal Oak, MI
> From: Graeme Suckling <graemes@saonline.com.au>
> Reply-To: Graeme Suckling <graemes@saonline.com.au>
> Date: Tue, 29 Apr 2003 11:29:58 +0930
> To: 'Guy & Pamela Pepoy' <gppepoy@cybertrails.com>, "Datsun Roadsters List
> (E-mail)" <datsun-roadsters@autox.team.net>
> Subject: RE: Installation of Exhaust Gas Temperature Gauge.
>
> Guy, I think the Roadster pre-dates the manufactures instructions by
> several decades.
> I would treat it like an O2 sensor and mount it at the closest point
> to the engine headers where all 4 cylinders can be monitored i.e. the
> collector pipe.
> I can't see the point in restricting the sensor to less than the full
> tote of exhaust gasses.
> Regards,
> Graeme Suckling
> 1965 SP310 - under construction DSOA Member # 112
> 1971 P510 4 door - daily driver, original owner, highly modified.
> 1972 PL510 2 door - in storage.
> 1973 HS30/240Z - re-building to 2003 specs.
> www.imagestation.com/mypictures/index.html
> Adelaide, South Australia.
>
>
>
>
> -----Original Message-----
> From: owner-datsun-roadsters@autox.team.net
> [mailto:owner-datsun-roadsters@autox.team.net]On Behalf Of Guy &
> Pamela
> Pepoy
> Sent: Tuesday, 29 April 2003 10:41 AM
> To: Datsun Roadsters
> Subject: Installation of Exhaust Gas Temperature Gauge.
>
>
> Greetings,
> I am installing an exhaust gas temperature gauge into my 67.5 stroked
> 1600. This involves drilling a 3/16" hole in my header to enstall a
> clamp style thermocouple that inserts into and clamps around the
> drilled
> hole. My question is....the gauge manufacturer states I should
> install
> the thermocouple into the "leanest cylinder as defined by the engine
> manufacturer". I don't have a clue. I suspect that with cylinder
> #1
> being closest to the water pump and #4 being closest to the fire wall
> that # 4 would be the leanest. That is my guess. Oh, I also have a
> solex set up on this puppy. As always, any suggestions will be
> appreciated.
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