Thermocouple location?

I'm running C.B.Perf 044 single spring, standard heads.....I would like to know the proper location to locate a thermocouple to keep track of head temp. I'll probably use a tab mount unit (8-32 or 10-32 screw mount). I'm planing on doing both heads....If it makes a difference, the car is a Spyder...

Looking forward to the info....

Leon C.

From what I've seen the closer you get to an exhaust port the better because you'll be recording the hottest spot in the head.

Isn't cylinder #3 the hottest part of the head....block...

depends if you are running a DTM. i have a V2 DTM (T4), so technically speaking - all should be equal.

I just installed a cylinder head temp sender and gauge last spring on my T IV. Per instructions, I put it under #3 sparkplug. It reads out at 350-365 F depending on road speed and ambient temp. If you do a google search, you will find lots of info on these, from many sources. One I read with some interest was from an airplane manufacturer who used Type 1 engines. Some users actually prefer to mount sender on a head bolt, because it reads lower than at the spark plug and gives an "average" engine temperature. I/m not comfortable with that logic, but to each his own.

I am going with a "K" type thermocouple around the base of the spark plug on cylinder 3.....My next question is, what are the "optimum" and "max allowable" temps for day to day driving, and the occasional max effort.....

Thanks again....

I believe T1 engines are in the 325 - 340 F range. Use the "search" tab for this forum and enter "cylinder head temperature" you should find a thread. If that doesn't work, google to "Shoptalk Forum" (anoher VW website), I might have read it there.

I might be wrong but I believe I've read 375 degrees.

Here is what VDO Instruments has to say:

Cylinder Heads on an Air Cooled Volkswagen are a weak point and can overheat if the air cooling system becomes unexpectedly blocked or if you're running in extreme (read: hot) ambient temperature conditions. An Oil Temp Gauge ain't gonna tell you as fast as a Cylinder Temp Gauge will if your head temps start sailing into the stratosphere. Average head temps on the upright engines range from 275 to 325F. Type 4 style engines tend to run a little hotter, averaging about 350 to 375F. These temps are when the Temp Sender Wire is correctly mounted to the Spark Plug, usually #3 because that's usually the hottest one. Some people have mounted the sender wire to other cylinder head locations, but our experience is that you don't usually have a true, reliable reading of the actual head temp. One very important thing to remember - NEVER cut and trim the length of the Temp Sender Wire or the Wire Harness - The voltage produced by the sender wire is what makes the Cylinder Head Temp Gauge work and if the length is tampered with, you will never get a true reading at all. Kit is complete with Gauge, Wire Harness and Sender Wire. All 3 items are available separately as well.
VDO-310901 Cylinder Head Temp Gauge Kit $110.00
VDO-310033 Cylinder Head Temp Gauge Only 600F $47.96
VDO-240701 Wire Harness - Sender To Gauge $14.26
VDO-323701 Temp Sender Wire-14mm Spark Plug $23.00

David...Ricardo....

Thanks guys....I am inputting into a Tecktronix DTM 520.....Digital read out and data collection.....The unit will monitor both oil and head temp at the same time.....It took me some time to modify the unit for data collection....Thanks again.....