CHT ,Cylinder head temperature gauge

neilca · 03-23-2011, 10:17 AM

I was running a CHT gauge using my spark plug to hold the sensor. Removing the plug finally destroyed the sensor. Where can I locate my sensor, it's a wire with a washer on it, so that it doesn't have to be removed as often as a plug?

cgarr · cgarr's Garage

If they are 3.2 heads with the cht on every head anyhow I would make a hold down to fit the threaded hole and mount it in that spot somehow but unless you have the engine out its going to be kind of hard to do.

neilca · 03-23-2011, 11:07 AM

Sorry I should have mentioned these will be 2.4 heads

KTL · 03-23-2011, 12:54 PM

I have mine installed on cyl. #3 and it's survived regular plug changes for 4-5 years. I remove the crush ring on the plug each time and i've also bent the tab of the sensor ring upward to lay parallel to the hex of the plug, but still allow the socket to get in there to wrench on the plug

Grady Clay · 03-23-2011, 02:45 PM

neilca,

What is your use?
How extensive data acquisition do you want?

I have engines with 12 head temperature sensors.
Six are on the little ‘flat’ where an exhaust air injector would be on the inboard side of the exhaust port,
The other six are in the intake runner web.
These are very small Type K thermocouples.
The wires run [u]through the inside[/i] of an 1/8” roll pin and then the junction formed.
I made a tool to press these into an 1/8” blind hole drilled ~3/16” into the head.
All the wiring stays under the fan shroud.

You are probably not going to this effort unless you have serious data acquisition.

The under sparkplug washers are a pita.

Best,
Grady

MyTurbo3.6 · 03-23-2011, 03:22 PM

Here's how I did mine...

neilca · 03-23-2011, 04:11 PM

I am just going to instrument one head. I just want to know if I am about to melt a head on my race car. Is there one head that runs hotter than the others like on a VW? I was thinking about just putting it on an exhaust stud. I had a lot of problems trying to get it to work under the plug.

neilca · 03-23-2011, 04:13 PM

Myturbo 3.6

Were are the fins on your cylinders?

sc_rufctr · 03-23-2011, 09:56 PM

Naked cylinders are sexy. This looks interesting. Is it OEM?

KTL · 03-24-2011, 06:04 AM

Quote:

Originally Posted by neilca

Is there one head that runs hotter than the others like on a VW?

Typically seems to be #1 or #4 cyl due to being so close, and off to the side, to the fan? On the few engines i've worked on, i've noticed the worst valve guide conditions seem to be on these cylinders too. Others have said #1 and #4 also suffer because of the heater tube takeoffs for heating the cabin.

3.3 930 Turbo cyls don't have fins on the top. The later cyls then returned on the 965 to fully-finned. I hear they were removed to increase heat in the cylinders for emissions.

JFairman · 03-25-2011, 08:08 AM

"3.3 930 Turbo cyls don't have fins on the top. The later cyls then returned on the 965 to fully-finned. I hear they were removed to increase heat in the cylinders for emissions."[/QUOTE]

I've heard they removed the fins on the top side to control or equalize head stud heat expansion rates on the top and bottom of the cylinder while running and cooling off after shutdown and stop possible oil leakage between the head and cylinder.

The bottom side of the cylinders is downstream in the airflow and the exhaust valves and ports in the heads are on the bottom side so the temps are hotter there.. 930 exhaust valve guides wear out alot faster than intake valve guides because of that.

Not really sure of all their reasoning for doing that and they changed to fully finned cylinders like normally aspirated motors on the 964 turbo.

I'd rather have the fully finned cylinders for better cooling especially on a modified motor if it was an easy choice.