Alternate cylinder head temperature mounting ideas

[esde]

I have a 600* vdo gauge in my car and while last changing out the plugs, for the first time I had a bear of a time getting the #3 plug through the sender ring and into the head with my hand jammed behind the carb and manifold. The ring would get caught up on the cylinder tin, or the plug threads, or wrapped around the socket, and I came very close to starting the plug crooked into the head as a result. I saw some aluminum on the first plug thread, stopped, and ran a chasing tap down the hole. In the end I stuck it into cylinder #4, figuring that something is better than nothing, and at least it's on the side known to run hot. But it got me wondering, surely there has got to be a better way?
Is there a better spot that could be drilled and tapped to more permanently install this ring? I have tried an upper center head stud and it does read low, I was thinking maybe one of the lower studs, or maybe there is a more ideal spot to drill and tap? A permanent stud could be installed to clamp the sender to, maybe where a second set of plugs is fitted for dual plug heads? Any thoughts?

[Cptn. Calzone]

I agree its a bitch to deal with ring and it can and will distort and leak or give a false reading.Some people have clipped the wires and jbwelded the wires themselves as close to the#3 plug with good results.In that same thread a few experts came forth and claimed it would never work.Ihave the ring in two seperate bus motors and will try the clipped wire method next time the motor is out as the ring is such a pain.
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71 westfalia
67 912 Porsche Quintilla
67 Single Cab aka my work horse

[jhoefer]

DO NOT just clip those wires. If there is not a good electrical joint between the two different special alloy wires your temp readings will be inaccurate, if it works at all and JB Weld is an insulator. The ends of the two wires are typically welded or brazed together. The ring is just crimped over them. You can trim back the ring, but do not mess with its crimp area. (You could try to pry the whole ring off but that has a high probability of damaging the connection.) You can epoxy what's left where you want.

[Boolean]

Or just weld the ends together again. Done with acetylene/oxygen. Just dont cut the leads shorter than necessary, as this will affect accuracy. An inch or less is ok.
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Build thread here:
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[Eaallred]

Under the plug is where it's at if you want a useful reading. That's as close to the valve seats as you're going to get, and that's the critical temp reading.

Get the valve seats too hot, and that's when they drop!

Anywhere else is just a reference number so you know when you're running hotter than normal. Which can work, as long as you know THAT is what it is and adjust your driving style accordingly to keep the temp where it is "normally". The actual number becomes useless at that point, just normal and not normal is what you are going by.
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Eric Allred

You have to remember something: Everybody pities the weak; Jealousy you have to earn.

[Stripped66]

I drill a small diameter hole above and parallel to the spark-plug boss and sink the thermocouple end down about 1/4 to 3/8 of an inch into the head.

Thermocouple stays in with or without the spark-plugs. CHT responds quicker.
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[andy198712]

would EGT be the fastest reacting? but i guess it wouldn't truly indicate head temp
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[Cptn. Calzone]

Stripped what holds the thermocouple in place?
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71 westfalia
67 912 Porsche Quintilla
67 Single Cab aka my work horse

[tattooed_pariah]

This was brought up sometime last year, and someone talked about a company that makes guages for ACVW aircraft use..

I cannot for the life of me remember the company now.. I was looking at one of their digital gauges that costs like $400 and had the ability to monitor four sensors, each sensor was like another $80..

anyone have any idea what i'm talking about or is my stupid question too vague? :/
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-pariah (just a novice from "that other VW site")
'72 Volksrod "Effigy"

"Never worry about stepping on people's toes. People who get their toes stepped on are either sitting down, or standing still on the job."
-Admiral Arleigh Burke, USN(ret.)

[Boolean]

These are some.

http://www.aircraftspruce.com/search/search.php?s=cylinder%20temperature
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I strive for perfection. Excellence will not be tolerated!
Build thread here:
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[tattooed_pariah]

[Stripped66]

[Stripped66]

[esde]

I'm understand what Eric is saying about between the valves being the most critical accurate temperature. If there's a way to get a stud mounted into that mass of the head that forms the chamber, just not the actual spark plug, is what I'm after. I think it would be pretty accurate, maybe a few degrees off from at the plug but close. In looking at some Mofoco heads, I have the idea that if I cleared a spot through the fins on the underside (above the push rood tubes) I could maybe tap into the head there. I guess it would be a matter of accurately drilling and tapping the hole, to hit the center of the area. The linked website has several senders that are available in 10mm ring, that would be perfect for what I'm thinking of. I'll post up a pic or two of what I'm proposing in a bit. SD

[Eaallred]

On my dragster I put an Autometer head temp gauge in it so I had a good reference of temp. I tapped a location right above the plug in the fins. I have "normal" and "not normal" temp reference now. I put a second on in above another plug and am now giving my EFI computer a "coolant" temp for warmup reasons that seems to be working well for what i'm doing.
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Eric Allred

You have to remember something: Everybody pities the weak; Jealousy you have to earn.

[esde]

Here is where I am thinking about. I can machine out a small circle in the fins centered where I have the screw driver pointed, and it seems the head is pretty thick there. I will probably contact Roy before doing it, but it seems like a good spot.

any thoughts on this approach?

[Eaallred]

If the sender is at "cylinder height", it should be fine. The cylinder seals on the deck surface, not the sides. If you are going past cylinder height, I'm not sure i'd do it.
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Eric Allred

You have to remember something: Everybody pities the weak; Jealousy you have to earn.

[DerekC]

[[email protected]]

[Stripped66]