CHT Nirvana (cylinder head temperature) gauge/sender FAQ

[scrivyscriv]

I think that's what DD was getting at when they say to only use the DD sender. running copper wire from a junction at the sender in the back isn't going to work well. You can get thermocouple wire all day long on eBay fairly inexpensively.., although the Chinese TC connectors are highly suspect, I would recommend getting Omega K-type instead of eBay China for those.

I never could get my poor man's DD to work right, it would fluctuate and indicate too low with engine running. Would only indicate the correct temp with engine off.
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Robert in Memphis
Dünkelgrügen 1967 Java Green bug thread
Engine rebuild thread
If you're ever in the Memphis area, you are welcome to stop by for advice and help.

[Randy in Maine]

Only the oil temp sender is the VDO one.

It cost about the same money to do it correctly.

[scrivyscriv]

[pittwagen]

Well let me ask this question. Can anyone say "from personal experience" that they connected the DD gauge to the VDO wiring and it worked or it didn't?

I currently have the VDO setup in my bus and other than doing the calculation when ambient temps are over 70 deg or 75 deg, whichever it is, I have almost 5 years of info to know what is normal for my bus and what is not. Rewiring, given my particular setup, is not easy. I do not use the thermocouple under the plug. Mine is wired like the Oranje Trophy bus.

So is it 70 or 75 that one adds or subtracts a degree from to get the actual CHT temp with the VDO? I have seen both reported on this forum. It would be nice if someone could nail that one down with factual evidence too.

[Tcash]

Continued from:
http://www.thesamba.com/vw/forum/viewtopic.php?t=6...highlight=

[airschooled]

[gereonb]

4-channel K-type Temperature Gauge = $32
4 * 14mm Spark Plug K-Type Thermocouples 12ft = $24

Now THAT is CHT Nirvana !

[scrivyscriv]

Just a heads up some gauges cannot handle a grounded thermocouple, which is what the spark plug ring is.. Any direct metal contact to the engine will ground the thermocouple and the gauge circuit. My poor man's Dakota digital would not read correctly with the engine on because it's not set up to use a grounded input. Which is why you see things like insulated EGT probes. A reciprocating engine aircraft CHT uses a similarly insulated CHT probe as well
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Robert in Memphis
Dünkelgrügen 1967 Java Green bug thread
Engine rebuild thread
If you're ever in the Memphis area, you are welcome to stop by for advice and help.

[SGKent]

[aerosurfer]

I have been very happy with my home made CHT setup using the poor mans DD thread.


http://www.thesamba.com/vw/forum/viewtopic.php?t=592584&highlight=poor+mans
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Rebuild your own FI Harness..My Harness

77 Westy 2.0L Rockin and Rolling Resto!

72 Sportsmobile (sold)
79 Tran$porter... Parts car money machine (gone)

[Dangermouse]

I like my VDO CHT gauge but have experienced my fair share of mussed up, ovalled out ring senders which get distorted on installation and removal. I thought I'd try and do better this time so here's something I tried. In my experience, the 14mm VDO ring sender doesn't easily fit over the threads of the spark plug out of the packet and needs to be made just a hair bigger to slip over the threads. A small grinding stone on a dremel tool works well for this -

In the past I've found that the soft metal of the sender (copper?) tends to want to distort when you bend it up so to keep everything held in place and flat I used a 14x1.25 spindle nut I found on eBay for a couple of bucks. With this threaded down against the sender and sandwiching it tightly against the plug I was able to reshape it with a small drift without affecting the close fit of the ring portion around the plug threads. I think I could have gotten an even closer fit around the body of the plug if I had ground down the crimped area just a little bit.

This made for a clean and distortion-free installation of the plug and cht sender; this is how I will be doing this in future. Maybe it'll be of use to somebody out there.
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[Lil Lulu]

Dangermouse- I did the same thing to my DD ring sender. It has lasted for 6 years now with no distortion and no leaks. It helps to form it to the plug before installing and then insert it in the hole as a unit. I think DD will sell a separate ring if it does distort.
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'65 Beetle "Lil' Lulu"- Ruby Red
1600 stock from '71 bus

'72 Deluxe - Niagara Blue w/pastelwiess Camper Special 2L dual 40 Webers 002

'74 Hightop Weekender "Dixie" 1800 34 Del singles

[gintaras]

Well, I routed my TC wire under the intake flange, in-between the tin and head, I think I am grounding out and getting the temperature of where the wires are hitting the tin, because it is almost always around 180-200

In order to fix this, I would need to remove the left side intake side, and insulate the wires where they touch the tin..
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1979 Deluxe Westy in Mexico Beige

[pierrox]

Thanks for this thread!
Just got mine in the post this weekend, that's pretty exciting!

How did you guys install it in general? Run the sender from under the plug through the tinware via the plug hole? Or did you route it under the tinware and exited somewhere... where?
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[Wildthings]

[Randy in Maine]

My sender clips to the one of the casting fins at the head and then exits in its own little hole (with a grommet) in the tinwork. Been here? It uses a little spring clip from a door or a "binder clip" that has been ground down on a grinding wheel.

http://www.germansupply.com/home/customer/home.php?gspage=customer/main/tech/cht/cht_install.tpl

[CarlosZ]

I’ve had the sender ring installed for over a year and finally hooked up the rest of the wiring and gauge prior to BBB 2018.

I installed the sender by cutting a wedge into the head by plug #3 and clipping the wire to a head fin. Not sure where the clip came from, might be piece of the interior but does the job. I routed the sender wire between two tin pieces. The sender has a protective sheath that I hope will prevent wear. I’ve removed the plug about 10 times and no ovaling or movement. The ring is sitting pretty on the head. I’d suggest you go the the cut in the head and clip for best results.

[furgo]

Quick question to those who've installed the sender: do you need to remove the crush washer/gasket of the spark plug when using the ring sender?

In other words, is the ring sender effectively replacing (and acting as) the gasket?
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'79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)

Decode your M-Plate

[Randy in Maine]

I leave the spark plug washer on.

[CarlosZ]

I've removed the plug washer.