Aircooled VW South Africa

Hi.

We are busy developing a affordable cylinder head temp gauge to be fitted under spark plug number 3.
This will tell you a lot of the state of tune of your engine. Overheating of a air cooled engine will often result in cylinder head damage to the valve seats, the so called "dropped seats"syndrome may buss drivers heard about or expierenced. This is a cheap way of saving your Kombi,Camper or Beefed up big bore motor.

You get them cheap at aviation shops
Straight forward thermocouple connected to a gauge

Could you give more detail on this item found at aviation shops?

Hi I also would like to have more details, cheapest gauge in that Deg c range is R750 what I could find.
This will have digital display and would cost way less than the gauge alone.

Bought my gauges and senders from a aviation supplier in Kyalami business park , cant remember what they were called this was years back , they had both options for gauges digital or analogue

It is just two different metal wires crimped togethar on a washer which fits to the sparkplug and connected to a gauge.
No voltage or nothing required as it generates its own voltage to an analogue gauge
You also get electronic ones which is programable to a alarm etc

They are called cylinderhead temp gauges or cht
You also get exhaust temp gauges or ext

Yes you are correct about the working of it. I did some research yesterday the cheapest Gauge I can ind now with the required Temp range is now R1050 .This system will be calibrated and way cheaper , the aim is making it affordable to the People .

Expanded the the display option to be able to connect 2 measuring points now for those with twin carbs . Only extra cost will be R110 for extra J tipe wire and fitting. Might have first ones ready for display at Kaapse Kombi Kult

just remember that these dont really read the head temp, but the temp difference between the hot and cold junction. i.e. difference in temp between the head and the gauge.
So if your head temp is perfect on a warm day and the next day its 20deg cooler but your head temp is exactly the same, the gauge will read 20deg hotter, making you think it is possibly overheating and leading to plenty confusion as to why the car would overheat in the cold but run fine in the hot...
So you need to make it known that when you say its calibrated, that it is calibrated to a temp difference between the hot and cold junctions.
Or are you building a properly compensated unit which does self compensation before outputting to the gauge? Dakota digital offer these but their price is a little high

I'm not saying your idea is bad, I'm just adding info to the topic.

Spot on Tony but then it gets complicated and expensive

There is a lot more then just reading a temp.

You need to have a multi sampler that can read temp at say 100 times per minute and then compensate for losses and ambient and then send out a average for the meter to display with buffing to stop the meter shuddering.

So now you can see why even the high tech manufacturers in mass production have expensive meters.

Be easier to have an 6 LED display which give you Green for under set temp. Orange for set temp, and red for over set temp.

Then you have two sets 3LED's per side, and these need to be under the head bolt, and not the spark plug as this is not a true reflection of an aircooled motor.

The correct temp reference for an air cooled motor is the oil. and not the heads.

OMO

Herman

not entirely true Herman, your oil can be fine while you are melting the heads (lack of cooling, dirt in fins, too lean AFR...)

Agree with Tony , I used these on the big bore type4 motors as we all know they love to drop a valve seat if the heads get to hot

Hi Tony , Yes it will have ambient Temperature compensation. Which was part of design (German the cost is R5).
This will be calibrated in a oven up to 250 Deg C and the temp compensation junction will be outside and will also be heated up cooled down to make sure there is no influence on the CHT connection whilst keeping temp steady inside oven.