| |
|
|
Cylinder Head Temperature (CHT) Gauge Installation How-To (page 1)
Written by germansupplyscott
The following information is to be used for reference only and Germansupply.com is not responsible for any modifications made to your vehicle. These instuctions are for information only and not a step-by-step guide. Please do your research and consult a professional before performing any modifications to your vehicle.
|
|
Why do you need a CHT gauge on your VW?
|
If you drive an aircooled VW, the CHT gauge will tell you a lot about the state of tune of your engine. VW busses with Type 4 engines, especially those with stock fuel injection, have a tendency to run hot. Overheating an aircooled engine will often result in damage to the cylinder head valve seats, the so-called "dropped seat" syndrome that many Bus pilots may have heard about, or experienced first-hand. A properly installed CHT gauge can help prevent this sort of catastrophe.
What is a CHT Gauge?
A Cylinder Head Temperature gauge is the 'missing' gauge on an air-cooled vehicle. Most vehicles are water-cooled, and every water-cooled vehicle has a temperature gauge on the dash which shows the temperature of the engine coolant. You have a warning that the engine may be overheating when your temp gauge heads towards the red. Without a temperature gauge you may never know if your aircooled VW is running too hot. Since air-cooled vehicles like vintage VW's and Porsches do not have any coolant inside the engine, we measure the engine heat by reading the temperature of the cylinder head in the spark plug area. This area of the head gets very hot and is an excellent indicator of the operating parameters of the engine as a whole. CHT gauges consist of a sender, a wiring harness and the gauge itself. The sender is usually a thermocouple. The thermocouple in a CHT gauge consists of two wires attached to a copper ring terminal typically placed under the #3 spark plug. The two wires in the thermocouple are different alloys. Having dissimilar electrical potential when heated, the thermocouple wires create a tiny electrical current. The CHT gauge interprets this electrical signal and displays a temperature. Because the current in the CHT circuit is so small, it is important to use only the wiring harness supplied with the gauge not alter it in any way. CHT gauges are manufactured by several companies: the ones germansupply.com sells are made by VDO, the OE manufacturer of VW gauges.
|
|
Choosing a gauge kit
We are using the VDO 360-142 kit, there are similar kits made by AutoMeter. The VDO kit comes with everything you need: a 2 1/16" cockpit style gauge, the wiring harness, installation hardware and instruction sheet. The VDO instruction sheet is useful, but applies to a typical motorcycle installation, so we are making our own suggestions based on our experience installing this gauge on air-cooled VW vehicles. Depending on your vehicle, there are several locations you can the gauge itself. In a Beetle, you can use an aftermarket gauge panel to locate the gauge in the centre pod. In a bus, you have different options. VDO makes a gauge mounting pod and rings that may be used in any vehicle. The CHT gauge wiring harness consists of two long wires which reach from the engine bay in the rear to the dash. Two additional wires are required for the gauge lighting, which come with the kit.
|
|
|
|
|
|
|
