Any accurate NON digital readout cylinder head temp gauges?

[mondshine]

I find it hard to believe that Westach would not ship to the UK.
It certainly would not hurt to ask.

I have used Westach products in several VWs, and always purchased then directly from Westach.

Good luck.

[Ben Middleton]

Thanks for the pic! Sorry if I wasn't clear but because I am in the UK, the availability of most of these US-made gauges is limited. There are some second-hand Westach products for sale in the UK at the following link but I wanted to know if any of these were the correct ones for this application:

Skycraft:

https://skycraft.ltd/collections/cht-egt

[mondshine]

Westach is still in business; https://www.westach.com/

The gauges in my 181 look like this:

[Ben Middleton]

[wheel607]

I used the Harley Davidson Stewart Warner greenline guage and with the motor running I shot the head where the sending unit is installed and after 5 minutes running, it was only 7 degrees off. I think, that is pretty good. Only use it for comparisson. I got the Harley sender that goes into the head.....welded up a boss, then screwed it in. I really dont like the looks of the new style digitals. I wanted something old school. REMEMBER comparisson only.

[raygreenwood]

[mondshine]

My Fluke 87 meter does not have a thermocouple socket.
I measure thermocouple MV output with standard leads clipped onto the thermocouple wires.

Plotted on a graph, the thermocouple output looks pretty linear.

[chrisflstf]

What kind of connector is on the thermocouple on the meter end? A Digital milivolt meter gauge sounds interesting.

[mondshine]

Just to throw some gas on the fire...
I have been using Westach gauges for over 20 years in various ACVW's.
For CHT, none of the Westach gauges are cold junction compensated, even the TSO stuff. They are calibrated for a 75ºF cold junction.
All Westach CHT gauges use a Type J thermocouple with 48" leads, which is long enough to reach from #3 to under the rear seat bench. Having the cold junction inside the car's interior will limit the cold junction error to ~25ºF, because by the time the engine warms up enough for CHT to be of interest, it's usually between 50º and 100º inside the cabin. Then, you do the arithmetic in your head to get the CHT.

Uma makes some nice instruments as well.
It seems to me that I have read someplace that Uma CHT gauges are cold junction temperature compensated. However, after looking through the Uma catalog, I have seen no mention of cold junction compensation. So who knows?

In any event, once you become accustomed to what is "normal" for your car under various conditions the CHT gauge will alert you when something abnormal is happening.

[Richard Roth]

Does anyone have any knowledge or schematics of how this type CHT gauge is supposed to be wired ?
It uses the ring type sender under the spark plug.

_________________
The problem with reality is that there's no background music !

1966 Empi GTV MKIV
1954 Kabriolett Beetle
1953 Porsche 356 1500S
1957 Cable brake standard model
1962 cable brake standard model
1956 23 window Samba
1960 Austin Healey 3000
1961 Corvair Greenbrier

[mikedjames]

I have been playing around with GM dashboard dial stepper motors, 0.5 degree resolution.
They seem to work quite well attached directly to GPIO pins of a microcontroller, running off 3.3 volts.
I am slowly working through making a replacement fuel gauge for a Late Bay with the hot wire fuel gauge that rots away.
Which has illumination based on a WS2812 LED module so the backlight colour can be changed , or change colour based on fuel level.

So you can have an analog input, or listen to e.g. PLX MFD traffic.

So rather than using moving coil meters, use stepper based meters.
_________________
Ancient vehicles and vessels

1974 VW T2 : Devon Eurovette camper with 1641 DP T1 engine, Progressive carb, full flow oil cooler, EDIS crank timed ignition.
Engine 1: 40k miles (rocker shaft clip fell off), Engine 2: 30k miles (rebuild, dropped valve). Engine 3: a JK Preservation Parts "new" engine, aluminium case: 26k miles: new top end.
Gearbox rebuild 2021 by Bears.

1979 Westerly GK24 24 foot racer/cruiser yacht Forethought of Gosport.
1973 wooden Pacer sailing dinghy

[crocteau]

[Floating VW]

[raygreenwood]

[crocteau]

[raygreenwood]

So....since we are on the subject of TC compensation....check this out:

https://www.youtube.com/watch?v=LKEZjhCWGyw

Here is the product data page with schematics, theory, operation and diagrams....and down on page 16 of 16.....the form factor. These compensation circuits are 3.20mm x 3.2mm max (some are as small as 2.80mm x 2.80mm) and as thin as 0.75mm and max of 1.10mm.

So in other words....we could fit these into a lot of different TC gauge enclosures.

https://www.analog.com/media/en/technical-documentation/data-sheets/ad8494_8495_8496_8497.pdf

Mouser electronics info'
https://www.mouser.com/new/analog-devices/adi-ad8494-ad8495-ad8496-ad8497-amplifiers/

Digikey has them....for $59 each.

https://www.digikey.com/en/products/detail/analog-devices-inc/AD8495-EVALZ/11483518

So...there are 4 models for different TC types. If they can work for what you need....$59 may be worth it. Ray

[raygreenwood]

[raygreenwood]

[Floating VW]

[Floating VW]