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scrivyscriv Samba Electrician
Joined: October 04, 2011 Posts: 2922 Location: Memphis
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Posted: Fri Feb 26, 2016 9:55 am Post subject: Re: CHT Nirvana |
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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. _________________ 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. |
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Randy in Maine Samba Member
Joined: August 03, 2003 Posts: 34890 Location: The Beach
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Posted: Fri Feb 26, 2016 10:54 am Post subject: Re: CHT Nirvana |
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Only the oil temp sender is the VDO one.
It cost about the same money to do it correctly. |
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scrivyscriv Samba Electrician
Joined: October 04, 2011 Posts: 2922 Location: Memphis
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Posted: Fri Feb 26, 2016 11:04 am Post subject: Re: CHT Nirvana |
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Randy in Maine wrote: |
... to do it correctly. |
A thermocouple wire is a thermocouple wire is a thermocouple wire.. its going to be an industry standard TC wire. I can only speculate on which exact type but it's pretty likely either a J type or a K type, I doubt at their price and performance point it's anything more exotic.
there's not really any reason to insist that buying their exact part is the 'correct' way to wire a gauge in. it might be the preferred way to do it, full stop. _________________ 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. |
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pittwagen Samba Member
Joined: November 08, 2005 Posts: 765 Location: North of the 49th parallel
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Posted: Fri Feb 26, 2016 3:49 pm Post subject: Re: CHT Nirvana |
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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. |
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Tcash Samba Member
Joined: July 20, 2011 Posts: 12844 Location: San Jose, California, USA
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Posted: Tue Mar 22, 2016 4:29 pm Post subject: Temp II sensor - Matching Gauge |
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Continued from:
http://www.thesamba.com/vw/forum/viewtopic.php?t=6...highlight=
mrcool wrote: |
I am looking for a gauge that will work with a temp II sensor. Has anyone found one, or found a gauge that can be calibrated? I much rather use the ports that are on the side of the heads than using a Spark plug adapter ring.
I actually have a 1983 Vanagon but with a CV Type 4 Air Cooled motor, so same team guys |
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airschooled Air-Schooled
Joined: April 04, 2012 Posts: 12721 Location: on a bike ride somewhere
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Posted: Wed Mar 23, 2016 11:48 am Post subject: Re: CHT Nirvana |
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pittwagen wrote: |
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? |
Part of what we pay for when we buy the DD gauge is the 14' thermocouple wire that the VDO gauge lacks. It is because of this that you have to compensate manually when using the VDO setup. Since you're used to your bus temperature trends, your money is probably better spent elsewhere.
An email I received from the VDO help desk:
VDO technical service email support wrote: |
The sender is a K type thermocouple and it is cold junction compensated. The length of the thermocouple wire is 12 inches before it goes to regular copper wiring. |
This means you'll technically be able to use the DD gauge, but it will give the exact same reading, plus or minus a few degrees.
Here's why:
The Tref point on the DD gauge is inside the gauge itself. On the VDO gauge, the Tref point is 12" from the sender end. The entire function of K-type thermocouples is dependent on knowing Tref and comparing it to the voltage change at Tsense. If Tref is not measured or controlled, your gauge will only be as accurate as the temperature fluctuations at Tref.
In plain English, this means the answer to your question is yes* *The catch is that it won't be any more accurate. VDO did not get back to me with WHAT temperature they use for Tref. So we can't answer that one for sure. Dakota Digital was far more specific in how they know Tref:
Dakota Digital wrote: |
Because the thermocouple only measures the temperature difference, the gauge has a temperature sensor so that the temperature at the gauge end of the thermocouple wire is known. |
_________________ Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com |
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gereonb Samba Member
Joined: February 10, 2016 Posts: 149 Location: Arizona
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Posted: Thu Sep 29, 2016 8:18 am Post subject: Re: CHT Nirvana |
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4-channel K-type Temperature Gauge = $32
4 * 14mm Spark Plug K-Type Thermocouples 12ft = $24
Now THAT is CHT Nirvana ! |
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scrivyscriv Samba Electrician
Joined: October 04, 2011 Posts: 2922 Location: Memphis
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Posted: Thu Sep 29, 2016 8:27 am Post subject: Re: CHT Nirvana |
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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 _________________ 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. |
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SGKent Samba Member
Joined: October 30, 2007 Posts: 41031 Location: Citrus Heights CA (Near Sacramento)
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Posted: Thu Sep 29, 2016 9:54 am Post subject: Re: CHT Nirvana |
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Quote: |
VDO did not get back to me with WHAT temperature they use for Tref |
Based on threads in other forums from some who are engineers - about 70F _________________ “Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin |
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aerosurfer Samba Member
Joined: March 25, 2012 Posts: 1602 Location: Indianapolis, IN
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Dangermouse Samba Member
Joined: November 23, 2005 Posts: 1266 Location: Beautiful New Zealand
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Posted: Mon Dec 05, 2016 7:34 pm Post subject: Re: CHT Nirvana |
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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. _________________ Do not follow me, for I may not lead. Do not lead me, for I may not follow. Do not walk beside me either; actually just bugger off and stand over there will you. |
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Lil Lulu Samba Member
Joined: December 08, 2007 Posts: 1745 Location: Mouth of the Columbia
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Posted: Mon Dec 05, 2016 9:29 pm Post subject: Re: CHT Nirvana |
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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. _________________ '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 |
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gintaras Samba Member
Joined: November 19, 2012 Posts: 523 Location: Louisville
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Posted: Tue Dec 06, 2016 6:12 am Post subject: Re: CHT Nirvana |
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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.. _________________ 1979 Deluxe Westy in Mexico Beige |
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pierrox Samba Member
Joined: March 06, 2013 Posts: 258 Location: Paris, London, The Alps, North Carolina
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Posted: Mon Jan 22, 2018 10:34 am Post subject: Re: CHT Nirvana (cylinder head temperature) gauge/sender FAQ |
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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? _________________ Our bus is on Instagram
instagram.com/biencuitbus |
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Wildthings Samba Member
Joined: March 13, 2005 Posts: 50338
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Posted: Mon Jan 22, 2018 10:44 am Post subject: Re: CHT Nirvana (cylinder head temperature) gauge/sender FAQ |
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pierrox wrote: |
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? |
I wouldn't run it through the plug hole because that would make it vulnerable to damage when you were removing and installing the plug. I added an extra hole in the tin coupled with a rubber grommet. |
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Randy in Maine Samba Member
Joined: August 03, 2003 Posts: 34890 Location: The Beach
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CarlosZ Samba Member
Joined: April 23, 2016 Posts: 319 Location: Los Angeles
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Posted: Mon Jan 22, 2018 11:29 am Post subject: Re: CHT Nirvana (cylinder head temperature) gauge/sender FAQ |
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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.
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furgo Samba Member
Joined: September 06, 2016 Posts: 944 Location: Southern Germany
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Posted: Mon Jan 22, 2018 2:15 pm Post subject: Re: CHT Nirvana (cylinder head temperature) gauge/sender FAQ |
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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? _________________ '79 Westy, P22 interior, FI 2.0 l Federal, GE engine (hydraulic lifters)
Decode your M-Plate |
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Randy in Maine Samba Member
Joined: August 03, 2003 Posts: 34890 Location: The Beach
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Posted: Mon Jan 22, 2018 2:21 pm Post subject: Re: CHT Nirvana (cylinder head temperature) gauge/sender FAQ |
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I leave the spark plug washer on. |
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CarlosZ Samba Member
Joined: April 23, 2016 Posts: 319 Location: Los Angeles
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Posted: Mon Jan 22, 2018 5:29 pm Post subject: Re: CHT Nirvana (cylinder head temperature) gauge/sender FAQ |
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I've removed the plug washer. |
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