Engine temperature sensor - has anyone added one?

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Jake2015
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Engine temperature sensor - has anyone added one?

Post by Jake2015 » Wed May 29, 2019 7:45 pm

After melting my #3 piston, I want to add a temperature sensor to monitor #3 and/or #4. I found a 12MM CHT SENSOR designed for air cooled engines to be attached under an engine bolt or spark plug. Has anyone added this type of sensor or any other?

Thanks
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Garrycol
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Re: Engine temperature sensor - has anyone added one?

Post by Garrycol » Wed May 29, 2019 9:21 pm

I put a Engine Watchdog TM1 on my Haflinger - works fine. https://www.ebay.com/itm/ENGINE-WATCHDO ... xyk99R3NSK

Here is TheHaflinger thread on the topic. http://thehaflinger.com/viewtopic.php?f=23&t=3636

Garry
1973 Haflinger AP700
1977 Landrover FC 101
2007 Range Rover Sport TDV6
1971 Jaguar Series 3 E-Type Conv
1957 Landrover 88" Station Wagon
1957 Landrover 88"

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rmel
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Re: Engine temperature sensor - has anyone added one?

Post by rmel » Wed May 29, 2019 11:15 pm

Of the 4 cylinders, #3 is runs the hottest. So it would be your best bet to monitor.

The best method is a Pyrometer directly in the gas flow of the exhaust header close
to the exhaust port.

I run with one/cylinder and it is a great way to keep an eye on the overall engine
temp esp. when your going up a very steep grade on a very hot day. VDO is among
the best, available at Summit Racing and other distributors.
https://www.summitracing.com/parts/vdo- ... gKKcfD_BwE

If you go this route invest in a SS bung to weld to the exhaust header, it's a TIG
job with the proper filler metal.
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q

one2many
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Re: Engine temperature sensor - has anyone added one?

Post by one2many » Thu Jun 06, 2019 10:25 pm

To monitor my engine oil temps/pressures I use both, an oil pressure gauge and an oil temp gauge (VDO). For cylinders and heads I occasionally point one of those temp guns with the red dots, mainly to see any temp difference between cylinders.

My oil temp sensor is mounted under the oil thermostat but I don't really think this is an ideal location, I plan to move it to my sump for better accuracy
1985 pinzgauer 712K factory 2.7lt civilian (RHD, 4 door K)
1979 Volvo tgb 1314a (under construction to om606 diesel/722.6 trans. Dual cab/tray)

steyr92
Austria
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Re: Engine temperature sensor - has anyone added one?

Post by steyr92 » Mon Oct 21, 2019 7:00 am

the mount for oiltemp sensor under the thermostat is intended from steyr as far as i know to sit there.
in the sump i think the influence is much bigger from outside temp. in my opinion the perfekt spot would be after the thermostat and the cooler because either its bypassed or not u would get the temp the engine gets.
i placed mine also in the intended spot because its easier but if the cooler and cylinder fins are in summer i barely get to 90 degrees. more intresting in winter to see when its warmed up
regards

hatzlibutzli
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Re: Engine temperature sensor - has anyone added one?

Post by hatzlibutzli » Sat Nov 23, 2019 11:15 am

My oil temp sensor is under the oil pressure sensor. There you get a picture of the "outgoing" oil temperature after the oil cooler. Therefor it reacts on both: higher engine oil temperatures as well as bad cooling e.g. due to low RPM

At central european conditions equal on highway as on steep mountain climbs I get readings up to 65 deg Celsius (149 deg. F) ... in the heavy sands of the Erg Oriental/Sahara Desert the peak was at 71 deg Celsius (160 deg F) ...

A cylinder head sensor on each would be nice ... haven`t found a good place for yet. The aircooled Deutz Diesel engines have an out of factory blind hole for that purpose ...

I would appreciate, if someone finds a good place ... the M14 Sensors to put under the spark plug, that work well on motorbikes and chainsaws don´t work on the Pinz´s due to lack of space ...

Regards from the Alps ... Simon

steyr92
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Re: Engine temperature sensor - has anyone added one?

Post by steyr92 » Thu Dec 05, 2019 1:40 am

according to my repairmanual, the temp sensor under the pressure sensor tells the temp from the incoming oil from the pump before the cooler or am i wrong here?

hatzlibutzli
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Re: Engine temperature sensor - has anyone added one?

Post by hatzlibutzli » Thu Dec 05, 2019 8:01 am

To my interpretation the pressure sensor is in the main oilstream after the oil cooler, but before the oil filter ... otherwise the readings would not make much sense ... since the thermostate opens not before 83°C towards the oil cooler ...

Regards ... Simon

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audiocontr
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Re: Engine temperature sensor - has anyone added one?

Post by audiocontr » Thu Dec 19, 2019 11:50 am

I'd love a sensor on each cyl. Would help with ton of troubleshooting and carb adjusting. Wonder if there is an inexpensive clamp on system that i could utilize?
1973 712m
(2) 1968 Haflingers 1 For Sale
1978 GMC Palm Beach
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rmel
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Re: Engine temperature sensor - has anyone added one?

Post by rmel » Thu Dec 19, 2019 12:03 pm

IMHO Pyrometer's are the way to go, best measure of chamber temperature. And
repsonds quickly to load and AFR.

Thermo-couples are another approach, added to each head with a shallow tapped hole.
But the response is slow due to the thermal mass.

I have Pyro's on each exhaust port on my 710 and one on #3 on the 712. You can
get VDO steel bung's that weld up nice with a Mig on the headers. The Pyro's thread
into the bung, they are SS so a direct weld to the header though possible involves
Tig with a bit more welding expertise needed. And once you have that done get the
headers Ceramic coated. That's a good way to get a bit of a heat drop out of the cabin
and better exhaust flow in the pipe.

I compromised on the 712 with one Pyro in #3 which is the hottest cylinder of the 4.
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q

one2many
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Re: Engine temperature sensor - has anyone added one?

Post by one2many » Wed May 27, 2020 6:08 pm

I must have not clicked the notify me button hence the delay in reply, but if still relevant...
My VDO sender is mounted before the oil cooler as I would prefer to know how hot it is getting before the oil is cooled.
This being the case I rarely see temps above 55*C to 60*C. The only time I see my oil warm up (summer I use Penrite 20w/60 extra zinc formula...winter I run Penrite 15w/40 extra zinc) is on days above 40*C during steep low range 1 climbs and occasionally on extended freeway runs with a constant speed of 95km to 100km per hr, I have the factory 2.7lt (TL) engine. On these occasions it can hit up to 85*C, on the rare 45*C days I’ve seen it approach 90*C but I’ve only observed this once or twice. Oil pressure has never changed despite what temp my oil is running at and I put most faith in this fact, if I had noticed any drop in oil pressure on the hotter days then this would give me cause for concern.
My factory 35 year old thermostat was an 87*and this is what STec and both USA suppliers were selling as replacements, note when I tested this old thermostat it was not completely opening when tested. Because Australian temperatures can often reach above 40*C I opted to buy a (Mahle if i remember correctly) 83*C oil thermostat as my replacement but I can’t notice any difference between the two. I’ll probably also get a new 87*C thermostat for winter driving but mainly for peace of mind...oil pressure is my main concern and that is always acceptable and unchanged.
All this being said these little air cooled work horses are probably over cooled by design, I can’t foresee any conditions in which I’d overheat this engine (racing being the exception).
On a separate note most water cooled engines in hot Australian conditions nearly always need rest periods after long steep hill climbing especially in sand...(even the Mogs up north in high humidity) trying to explain to people that my little 4cylinder air cooled will take as much as you could possibly throw at it without it blinking an eye is always met with disbelief....Toyota/Nissan owners always know better despite never having had the benefit of any Pinzgauer experience. The Steyr engineers did a great job designing this little commercial grade engine. My favourite part of the design is the gear driven cam timing, the same as all heavy commercial truck engines (and the early Subaru ea81 which are commonly found in light aircrafts). There’s a reason why cam belt engines don’t fly.
A simple more accurate oil temp monitoring system would be welcomed by me but if my oil pressure is good then I’m confident that my oil is performing as expected.

RMEL I also use a pyro (for mixture setting when LPG tuning) but do you think exhaust gas temps are giving you accurate oil temp or pressure information? I’ve always considered these to be relatively unrelated. But I’ve never given the two much thought in relation to each other.
Cheers Warren.
1985 pinzgauer 712K factory 2.7lt civilian (RHD, 4 door K)
1979 Volvo tgb 1314a (under construction to om606 diesel/722.6 trans. Dual cab/tray)

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rmel
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Re: Engine temperature sensor - has anyone added one?

Post by rmel » Wed May 27, 2020 6:53 pm

RMEL I also use a pyro (for mixture setting when LPG tuning) but do you think exhaust gas temps are giving you accurate oil temp or pressure information? I’ve always considered these to be relatively unrelated. But I’ve never given the two much thought in relation to each other.
Pyro's are good for whats going on in the chamber. For Oil I have Pressure and Temp gauges.
Though what causes the Oil to rise in temp is combustion in the chamber but there's a lot
of inertia in the systems so it's good to have all the above.
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
Rescue Pinz: 73' 712M

Driver: Ron // KO0Q

ChickenPinz
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Re: Engine temperature sensor - has anyone added one?

Post by ChickenPinz » Wed May 27, 2020 7:13 pm

The real challenge for combustion sensing is probe placement. For air-cooled engines, most of my experience is from my aircraft and we primarily look at EGT and CHT. EGT is generally a probe drilled in the exhaust pipe just past the exhaust port of the head, and they are *very* sensitive to small changes in placement as the temperature profile of the exhaust gases is anything but uniform. Thus, we tend not to look at absolutes, but rather at delta-T for each cylinder, and don't get too worked up about cylinder-to-cylinder differences.

CHT is a different animal, and we really care about *absolute* temperatures. I don't know the metallurgical limits for Pinz heads, but on aircraft we like to be below 380F, if not accept below 400F, start to get excited at 420F, and get fearful at 450F.

CHT is a hard one on the Pinz as far as I can see. Aircraft heads have ports that are designed for CHT probes, and those locations have been thoroughly analyzed and selected. On a Pinz, we have no such spot.

What we want is the hottest spot on the head so we correctly measure the stress on the aluminum alloy. You can always attach a sensor, or point one at your favorite spot, and it'll give you a reading that goes up with true CHT, but we really need the hottest point -- not the most convenient point to put sensor. So just because someone says they have a "good" spot, you really need to understand their metrics for "good".

What I'd really like to do is use a FLIR camera to look to find that hottest spot, but have recently lost my access to that $25k unit that'd work.

Keep in mind I'm an engineer, and a sensor engineer at that, so I'm looking for the best spot. If all you're looking for is something to compare one day's operation with another, then just find a convenient spot as close to the combustion chamber as you can and as isolated from airflow as you can and call it good.

Oil temps are so much easier to measure! FWIW, on my flight this morning (TN550 6cyl 310HP engine) on a warm day I see oil return temperatures around 200-210F.
710K

one2many
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Re: Engine temperature sensor - has anyone added one?

Post by one2many » Wed May 27, 2020 9:16 pm

When I first installed LPG on my 712 I had a slight concern about cylinder head temps increasing but these concerns were quickly eased when I could see no difference between petrol and LPG. Not really being concerned about melting the heads on my 712k the metallurgical limits aren’t really something I’ve been factoring in.
I had considered fitting a small temp sensor to each cylinder head with the ability to switch a warning light or .... Bad Pic below but you should get the idea
30D0FDCD-9C75-46C1-AFFE-12250EBD1277.jpeg
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I decided against this mainly because I couldn’t detect any difference between either fuels (running petrol and LPG, duel fuel). With my red dot temp gun thingy, and because of the reasons you (chickenpinz) stated above being ideal location and having to drill and tap my heads no matter how shallow. If I was flying my 712 I might consider knowing exactly what the engine was doing an important factor if I didn’t like the idea of falling out of the sky but for me keeping an eye on the oil temperatures during different conditions and seeing no drop in oil pressure is good enough for me. If my oil was getting excessively hot I would expect to see a drop in oil pressure, but this has never even looked like happening even on 40*C and above whether.
Chickenpinz keep us all posted on the solution you come up with.
Has any board member ever overheated a Pinzgauer air cooled engine to failure point? That is with sufficient oil and the cooling fan and oil cooler all running as designed?
1985 pinzgauer 712K factory 2.7lt civilian (RHD, 4 door K)
1979 Volvo tgb 1314a (under construction to om606 diesel/722.6 trans. Dual cab/tray)

one2many
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Re: Engine temperature sensor - has anyone added one?

Post by one2many » Wed May 27, 2020 9:55 pm

audiocontr wrote:
Thu Dec 19, 2019 11:50 am
I'd love a sensor on each cyl. Would help with ton of troubleshooting and carb adjusting. Wonder if there is an inexpensive clamp on system that i could utilize?
quote=audiocontr post_id=89103 time=1576777845 user_id=10512]
I'd love a sensor on each cyl. Would help with ton of troubleshooting and carb adjusting. Wonder if there is an inexpensive clamp on system that i could utilize?
[/quote]

These Innovate exhaust gas readers are great for basic fuel mixture tuning, achieving the desired/correct air fuel ratio (stoichmetric). You can simply clamp the oxygen sensor into the tailpipe for basic mixture setting or re jetting your carbs for altitude etc. They are also great for LPG tuning when used in this manner as well. FYI the black box can be eliminated and a simple dashboard gauge can be used instead for the purpose of keeping an eye on the air/fuel ratio of your cylinders fitted with oxygen sensors. However the black box does have a data logging capability...dashboard clamps are available for this unit which is approximately 100mmx200mm.
10ACE063-B9EE-4420-BCC3-499A4D364240.jpeg
10ACE063-B9EE-4420-BCC3-499A4D364240.jpeg (961.79 KiB) Viewed 410 times
You’ll see the stainless bung RMEL spoke of as well, these can be added to one pipe (hottest cyl) as production EFI cars do or use two after first the Y joins (4cyl) . For pinz just before the heat exchanger, or go all out as RMEL has in his 710 and put one on each header close to the cyl heads. I’d consider this overkill unless you were converting to fuel injection or probably still overkill unless you were doing an independent throttle body EFI as designed for the bikemaker 712.
Which reminds me what happened there? Did the forum get any more information on how that work of art performed? It Looked really promising with the using of the relatively cheap production motor bike ITB’S. anyone heard how that turned out after testing?
1985 pinzgauer 712K factory 2.7lt civilian (RHD, 4 door K)
1979 Volvo tgb 1314a (under construction to om606 diesel/722.6 trans. Dual cab/tray)

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