CHT - Cylinder Head Temp gauge - where to find one?

[Craig 930 RS]

Seems like a good idea to have one - where can I find one to hook up to my 3.6?

[scottb]

Jack Olsen has a recent lengthy thread on this issue. Do a search.

[JTL]

I bought a vdo voltmeter and cht gauge from summit racing a couple of years ago. The cht ring lead mounts in place of a spark plug washer. It works pretty well.

jt
-84 targa

[Jack Olsen]

Pelilcan sells the gauge (incl. sender and wiring kit).

[911teo]

I love it. How big is it? Where would you put it?

[Porsche virgin]

**I bow my head and shield my eyes as I directly address The Olson, owner of the revered Black Beauty**

Mr. Olson, what are you thoughts on airplane-type gauges such as these?

http://www.aircraftspruce.com/catalog/inpages/westfaa_egtcht.php

[911teo]

Those are very similar (VDO cht) to the ones pelican sells.... What am I missing?

[derek murray]

I have the VDO model from Pelican and it fits very nicely along side a voltmeter where the radio used to be.

Others have replaced the clock with a CHT gauge. This will take some work as the VDO CHT gauge and the clock are different sizes. At one time North Hollywood Speedometer would fit a clock gauge with the CHT gauge for about $90.00.

[Determined]

I have two Stewart Warner gauges, good quality and brand new. Unfortunately, I'm using both on my project but you can find them every once in a while on Ebay if you search for it (search using different words, for example, head gauge, cylinder head temp, SW head, etc..you'll find one). I paid pennies on the dollar for them. Good luck!

Alex

[Joeaksa]

I work with airplanes and usually recommend their parts as they are rugged. Problem is that if you take a Ford voltage regulater used on a car it costs $20 at your local auto parts store. The very same regulator that has the cover nuts safety wired on costs $200+ at a aircraft parts store! Its the same bloody part in many cases!

That said, when looking for parts like this look for parts for an Experimental airplane. They do not go through the same certification process as normal parts. This means that they are just as good but a lot cheaper. Its the certification (read trying to keep the lawyers off of your back if something happens) that drives up the prices.

Try Aircraft Spruce, Chief Aircraft supply, Wag Aero, Univair, Wicks and so on for anything aircraft.

JoeA

[Craig 930 RS]

OK, good info.
Now.....what is the normal range of CHT temps (vs. oil temps, perhaps?)
so that we can make this a useful tool!

[Fl Ted]

I also have worked in the aviation world for many years, including a Porsche-powered Mooney! (didn't work out very well)
The biggest thing for engine monitoring systems in the last 15 yrs was and still is the CHT/EGT scanner that has probes for both on EVERY cly!!
They used to use just one CHT on the cyl that ran the hottest under NORMAL conditions. The EGT was placed in the collector, and monitored the combined EGT of all cly. Thats fine as long as nothing goes wrong.
BUT the whole idea of monitoring these temps is to alert you when something DOES go wrong, and of course, that can happen to any cyl!!
So, IMHO, a single probe is better than nothing, but if you want to catch a cyl headed south BEFORE it becomes toast, monitoring every cyl is the only way that makes sense.
I dont think multi-cylinder systems are available for cars, but an aircraft system could be used with some adapters for CHT. EGT simply requires drilling a 1/8" hole in each exhaust runner.
These systems make engine trouble-shooting a simple matter also.
No, I have not done it (just got my car a week ago) but I'm starting to aquire parts for adding a turbo to the stock 3.2, (low boost) and I will research the possability of doing it then.
Ted

[emcon5]

Pelican carries the VDO version, with sender that goes on a spark plug.

Tom

[Emission]

Originally posted by Craig911
OK, good info.
Now.....what is the normal range of CHT temps (vs. oil temps, perhaps?)
so that we can make this a useful tool!

I agree, what is the normal range?

The Pelican gauge measures 100-600... that's a pretty wide range. I'd rather see a more accurate, narrow range (digital maybe).

[Joeaksa]

Again, you do not want to see anything over 400 except for short time periods. Some people take theirs up to 450 but thats just asking for problems.

Would feel that 100-600 would be fine, or even 500 for a max. Truthfully I doubt that with the engine running you would ever see temps as low as 200 so a gauge going from 200 to 500 would give you more range.

Most drivers will not be watching the CHT as much as the other gauges. The temp varies with load and airflow, not to mention mixture. On planes this does not change that often, on cars its every shift or corner.

Ted, took a Turbo off of a plane years ago and grafted it to a 242 Volvo. Very nice sleeper and lasted for years. No change in compression as long as you keep your foot out of it and limit the boost. Lots of fun!

JoeA

[KTL]

Just cruising around suburban streets, my VDO gauge is always sitting @ the 300 mark.

Also, be aware that a run of the VDO CHT gauges were wired backwards internally. I spoke to a VDO representative about this issue when my new gauge didn't work. I received a gauge that:

1. Did not "zero" when disconnected.
2. When connected per the instructions (+ to red wire, - to black wire) the gauge would decline/read backwards.

Therefore I returned it for a replacment gauge. The replacement was "zeroed" correctly, but I still had to swap the wires to get it to read a temp. So if anybody buys a VDO CHT, make sure to reverse the wires if you don't get a reading on the gauge!

[Jamie79SC]

Since we can't change mixture on the fly, is there any need for EGT?

[Porsche virgin]

I am considering the aircraft version because it has two gauges in one for only $115. I figured I'd put a sender on the 2 and 5 cyls. My main concern is watching temps when I get stuck in traffic in the summer and the car just idles. I also assume that the aircraft versions (as Joe alludes to) would be more reliable and accurate.

[fireant911]

Originally posted by Jamie79SC
Since we can't change mixture on the fly, is there any need for EGT?

It is not possible on your 79SC but I can indeed change the mixture while driving my 81SC - from 14.7 AFR to approximately 13.2 AFR with a flip of a switch (closed loop to open loop electronically controlled).

A side question - of the two, which is more advantegous to have a CHT or EGT?

[Fl Ted]

C'mon guys, think about it! EGT is not just to monitor mixture adjustments, it's main value is to alert you to too lean a mixture, like when an injector clogs and you fry your valves.
Ted