Engine Temperature Monitor

[AustHaflinger]

On my Landrover 101 I have a Engine Alarm system that tells me if the engine block/head metal (not coolant) is getting hot and if I have low coolant in the system. It tells me if I have a sudden coolant loss and if the engine metal is getting hot even if the coolant temp is OK.

You can buy a cut down version which is just a metal temp alarm and I have bought this version for my Haflinger.

https://www.ebay.com.au/itm/ENGINE-ALAR ... 2749.l2649

As I said it measures metal temperature not air temp or oil temp so the sensor needs to be bolted to a part of the engine that will result in the hottest metal when air is hot and oil is hot.

My thoughts are that the hottest part of the engine are the heads near one of the exhaust valves so ideally a lower head bolt but you cannot get to them as they are covered by the rocker covers. I noticed that the tinware bolts to the head either side of the spark plug so may be bolting the flat sensor on the inside of the lower tinware bolt may be suitable.

Any thoughts??

When setting these things up, the absolute temperature is irrelevant as what you are looking for is a change from "normal". When setting up you bring the temperature of the engine up to normal operating temperature and note the temp on the gauge - say 80 degrees C and you need to remember this. You then set the alarm for about 10/15 degrees hotter to take into account increases in environmental temps and its impact on the engine and its temp - so you have a digital readout of engine temp but also an alarm if it gets hot.

On my 101 system the usual metal temp of the head is 75 C degrees and I have the alarm set for 90 and while it has got near there when stopped with the engine running on a 40 degree day it has never got there. The alarm has gone off with the coolant level was a bit low but not an issue for the Haflinger.

Now you could put in a oil temp gauge but it is a bit more cumbersome to instal on the limited ports I have on the oil pump.

I will post a followup in a while after I have installed it and tested it in hot weather.

Garry

[heinkeljb]

Use the left hand head and the screw the holds the tin ware on just behind the distributor as this is likely to be the hots place you will find easily. Left hand cylinder runs hotter than right hand side due to the oil cooler reducing the air flow over it.
Other place to put it might be the exhaust manifold bolt under the left hand cylinder.

John

[AustHaflinger]

Use the left hand head and the screw the holds the tin ware on just behind the distributor as this is likely to be the hots place you will find easily. Left hand cylinder runs hotter than right hand side due to the oil cooler reducing the air flow over it.

Thanks John - I hadn't considered that - makes a lot of sense.

I did think about the stud on the exhaust port but being the bottom and open to outside airflow it probably will not get as hot the engine cooped up inside of the tin ware - I will try the area behind the distributor.

Cheers

Garry

[AustHaflinger]

I got my new toy in the mail on Thursday - so today I thought I would give it a quick test before I hard wire it in. Somewhere easy on the engine and as it has a 12v plug I could plug it into my 12v socket.

So I bolted it to the inlet manifold stud on the left hand head and went for a drive. Outside temp was 18 degrees and once warmed up the temp settled down to between 55 and 60 degrees C in normal driving.

What was interesting was that when going down hill temp increased and when going up hill temps went down which does not seem logical but when doing downhill I am still in 5th so revs and the cooling fan are lower so while the engine is not generating a lot of heat there is less airflow around the engine. When going up hill, I am normally back in 4th with engine revs up over 4000rpm so the fan is putting lots more air over the engine.

After a bit of a run and when stopped with the engine idling, the temp went up over 70 degrees as air flow is at a minimum. However to show how effective how the cooling fan actually is, when I finally got back home and switched the engine off the temp went up to 112 degrees so even at idle the fan is cooling the engine quite well.

It was only 18 degrees today so it will be interesting to see what happens with engine temps when we get up to 40 degrees C in the middle of summer.

Garry

[Ole]

There is also more air (and fuel) going thrugh the intake manifold at higher load and that could effect the temperature where the probe sits.

[AustHaflinger]

Yes very possibly - when I get around to do the installation I will put the sensor down lower on the engine on the left cylinder where airflow is harder to get too - probably as I first indicated - where the tinware bolts to the heads lower down near the exhaust port.

Cheers

Garry

[heinkeljb]

Gary,

If you put in on the tinware just behind the distributor, it will not get any real "outside" airflow over it and will only get the "heat sink" heat that dissipates through the metal.
It will probably show much higher temperatures during your summer as it can only show the temperature of the barrell.

If you really want cylinder head temp, then you could take the piece of tinware off under the left hand cylinder and put the sensor on one of the oil drain bolts. It would get covered up and not be influenced by road wind blowing over it.

John

[wojo12]

I believe my engine temp on a long run is too high. One of the related problems is that I think the fuel is vapourising. I'm just wondering where the factory fuel pump is mounted on an original Aussie delivered 700APT? It appears that my car is missing ducting which would run from the main housing outlet to the vertical engine cover.

Any assistance/advice appreciated.

[heinkeljb]

Welcome Wojo12,

Factory fuel pump is mechanical and fitted on the right hand side of the engine as viewed from through the lower engine hatch. It is down near the tinware that separates the top part of the engine from the outside world. If you have the governor still fitted to your engine, it is down and behind that.
Another way to find it is to follow the oil filler tube down to where it joins the crankcase and then look below that.

It is possible you have an electric fuel pump fitted, but without pictures to see your engine bay, we would all be guessing.

If you are really having issues with fuel vapourisation then you could make up a blanking plate and fit it in between the joint of the fuel pre heat tube that is fed from the left hand exhaust pipe up under the carb.

If I remember, I will post a picture of the joint which you would undo, slip a piece of sheet steel or Aluminium in between the two pipes and do it back up again.

Another method to reduce vapourisation is to take the carb off the manifold mounting bolck and put two fibre gaskets in there - that would reduce the amount of heat being transferred to the Carb and hence to the fuel.

John

[wojo12]

Thanks John. Mine has an electric pump, mounted 20mm from the right barrel on the removable access plate!!!

[AustHaflinger]

With either pump you will not get fuel vapourisation between the pump and the carb as the pressure of the pump will prevent this. It is different with the pipe from the fuel tank to the fuel pump on a hot day as the suction of the pump could cause vapour lock.

The issue of the carb itself is a slightly different matter because of the carb heater pipes from the exhaust heat the base of the carb - great for cold northern climates but not so good for hot Aust summers. I was going to blank mine but as my winter temps are similar to those in the UK my mechanic indicated I should leave mine as is - in Qld I would blank the carb heater pipes at the joining flange.

In my case, my engine has no issue idling in winter up to about mid Spring when the temps start getting over 30C. Then my engine will not idle and is simply a result of heat soak in the engine. I went to my local Mercedes independent mechanic who has lots of parts and got two extra fibre spacers plates that go under the carb to help insulate it further and it has worked to an extent but is not perfect. When I next to take the inlet manifold off I will blank the carb heater pipes and see how I go without carb heating.

If the tin ware is correctly fitted, fan working well and your oil cooler is in good condition with no blockages the engine does not have an issue with Aussie temps. Mine worked for a few years in the West Australian Gold fields with no issues and there are articles around of a haflinger that wandered around the deserts with a 200litre fuel tank on the back - again with no issues - this all assumes that all is good.

I have fitted the temp gauge to give me early information on possible issues if all is not well. Easier than fitting an oil temp gauge.

Garry

[AustHaflinger]

So I bolted it to the inlet manifold stud on the left hand head and went for a drive. Outside temp was 18 degrees and once warmed up the temp settled down to between 55 and 60 degrees C in normal driving.

It was only 18 degrees today so it will be interesting to see what happens with engine temps when we get up to 40 degrees C in the middle of summer.

Garry

I still only have this fitted up as a temporary arrangement but it works well.

Today is a nice summer day - clear and a nice 36°C so I thought I wound see what happened with engine temps in the heat. I drove for 34km an included a drive up a local hill that rises 250m above the lake and is a steep drive.

So when it was 18°C the engine temp was showing around 60°C and today with outside temp up at 36°C it showed engine temp around 70°C which is pretty good. Like before the more the engine is revved with its associated increased air flow the cooler the engine ran. Climbing the hill (which is steep) at 45kph (4500rpm) in 3rd gear temps dropped to 68°C and where I could change up to 4th gear temps rose to 75°C as revs and airflow dropped. Coming down and in a high gear and using the brakes to keep speed down temps were back up around 75 to 80°C but as soon as I used lower gears to slow the vehicle temps dropped. If in a water cooled vehicle temps would have risen climbing a hill like that on a hot day.

On the way back home I was doing 80kph on the freeway with the engine up at 4500rpm and temps dropped to 68°C but as soon as I stopped at the lights and then commuted through the suburbs using lower revs temps started to rise to between 70 and 75°C.

So it would seem that higher outside airtemps are no such an issue for the Haflinger - the more you work the engine the more the fan is putting air through, if anything you need to watch low rpm circumstances like idle and slow driving where there is less air going over the engine.

If an aircooled Haflinger were to be designed today - an electric fan that runs on engine temp would be a better option than the 50s arrangement it now has but it still works well.

Garry

[Ole]

Thanks for testing this Garry. Now I don't have to do it to satisfy my curiosity.

[AustHaflinger]

There was recent discussion on installing the little rubber grommets that go on the spark plug leads to seal the cooling air inside the tinware and not allowing some of it to escape from around the spark plugs - I contend that it is not really an issue based on my experience with hot Australian summers.

Today it is 36°c here (today is the average hottest day on record in Aust) so I thought I would check on my engine temps when driving around.

The TM1 sensor is bolted to one of the left inlet manifold studs in the head. So driving around at 4000rpm engine temp sits around 78°c - lower revs and the temp rises, higher revs and the temp lowers - so when going up a steep hill in lower gears where the engine is revving high the temps are lower which is a bit counter-intuitive but as revs rise, the fan goes faster so more air is blown in the engine.

This became pretty obvious when I got into heavy stop start traffic where revs are low and the engine is often at idle, so air flow is low - here temps rose to over 95°C and getting my chicken and chips in a takeaway drive through, I have to keep revs above 2000rpm to keep temps below 95.

The interesting bit is when you park and go to do some shopping - the heat soak in the engine is huge - once when I came back after a while, the temp showed 130°c and the engine started and ran fine at 130°c but the airflow soon cooled the engine down to around 80°c when driving around.

So higher revs mean a cooler engine, normal summer operating temp is about the same as a normal water cooled engine, the engine temps can get up around 130 but the engine still runs fine - so the trick is really just drive the vehicle but try not to let it idle for long periods when outside temps are hot as this could raise internal temps to a high level - but a few revs gets the airflow going and reduces engine temps.

Garry