cylinder head temp sensor placement
 

I am rebuilding my 86 930 and am thinking about installing some temperature sensors on my cylinders/heads. Where are the strategic locations? Is there an advantage to more than one sensor (ie. on cylinder 2 and 5?)? I assume that an inexpensive thermistor will work fine and what is the best way to attach a sensor? Is high temperature hookup wire like teflon necessary?

i know the two stroke karting guys have a simple head temp system. i dont know much about it. maybe you can search there? sorry i am not more help.

cliff

Just thought I'd throw this out...

Aircraft engines are generally aircooled. Some are turbocharged. Maybe you should look at places like Chief Aircraft or Aircraft Spruce for ideas.

Good luck, and let us know what you find.

The VDO system I use has a temp sensor that installs at the spark plug. I use the #2 cyl. Works good, lasts a long time.

cylinders 3 followed by 4 are where issues generally arise

I might have the cyl # wrong. I use the middle left side cylinder.

Norm I was going to use my Autometer Pyrometer in conjunction with ‘5248 cylinder head temperature spark plug probe’

http://hp.autometer.com/products/accessories/pyrometer_accessories/pyrometer_accessories.html

Norm,

The aircraft gauges typically use thermocouples ... either under-the-sparkplug or pipe-thread type sensors.

There was quite a discussion of cylinder-head temperature gauges in the following thread:

http://forums.pelicanparts.com/showthread.php?s=&threadid=75848&highlight=thermoc ouple+gauge+B50

In addition ... I failed to make a good case for the use of the military surplus Lewis Instruments gauge by not mention that it was designed to work on either 24 Volt or 12 Volt electrical systems ... all you have to do is supply 12 - 14 Volt power at the appropriate terminal! Two Type K thermocouple probes from Aircraft Spruce is all I needed for a functional dual CHT gauge -- for under $100! There is a nice location for it on an old SC console assembly bought off eBay.

http://forums.pelicanparts.com/uploa...-LewisInst.jpg

Thanks to all of you. I've got some good ideas now!

p.s.

I now know that Westach (and probably others) sells thermocouple sensors that mount under the spark plug. I'm going to monitor all 6 cylinders with type J sensors, a dual CHT gage and a 3 position switch. It might be overkill but maybe not.....!

"cylinders 3 followed by 4 are where issues generally arise" because of the ari flow limitations.

Also, note where PAG put the sensor on the 3.2L engines.

Good luck.

Warren,

Do you happen to see any part numbers on that gauge? Every aircraft place I've checked is asking for a part number.

Thanks.

I'd like to know the p/n too. It's a lot funkier looking than my data logger....

As a long-time thermistor hater, let me just advise the original poster to either use the VDO setup or go with thermocouples. Omega is the big boy for selling all sorts of temp. measurement stuff.

This should provide you plenty of information: Chief Aircraft

They even have a kit with six probes, and a gauge the can be switched to monitor the temp on all of the cylinders (one at a time). It's part number EI E6.

Scott B and Norm Reed have a good idea with the ability to monitor all six cylinders. I used a 6 cylinder digital CHT guage on my aircraft as an inflight engine analyzer to make sure (amoung other things) that all my injectors were performing properly, small aircraft engines don't have any computerization and are manually leaned or richened during flight.

A similar CHT package would make a great monitor or analyzer for any of the 911 engines especially injected models. Properly monitored it should reveal a long list of potential probelms before damages result (like a leaking cylinder to head mating surface when a stud fails, resulting in a cooler cylinder in relation to the others).