help to identify the best possible place for oil temp sender

deQuincey

deQuincey

Quousque tandem...?
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hi

I am trying to receive more detailed info of the engine performance and running variables, such as oil pressure and temperature

I will use vdo instruments, and more or less the position of all sensors is ok, but i have a big issue with the oil temp sensor

I assume there is not a single free threaded hole in the engine block that can be used for this purpose, so I have identified one possible point for this sensor: the oil drain hole screw in the bottom of the engine

the process is self explained in the following pics:

fa0enp.jpg


2ugdnnq.jpg


xp25no.jpg


6jetg5.jpg


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now the question is, is this one a good temperature meassuring point, despite it is too low and the cables and extra lenght of the sensor may be causing problems (in the event of passing a bump, or similar), my question is:

is the oil temp, meassured there, representative of the oil temp in the engine ?

I assume that the max temp of the oil will be located in the vincinity of the cylinder head, which is a non accesible point for sensors,

but also I consider that all the oil is being moved around by the oil pump, so....

I consider that the three ways of thermal transmission will be intervining in some way, so conduction and convection will play an important role (i will say radiation is negligible), so not only the oil itself but the engine walls will heat the oil up

also I assume that the lower engine cover, which is the final oil reservoir is being cooled by the air passing below the car, so...

please advise, identifying any other easy locations for this sensor, and/or discussing the accuracy of the choosen actual location

regards
 
Hello,

While I'll say up front that I am no engineer or motor expert. Just that I have my oil temp sender located in the same place, oil drain plug and I believe my brother has it in the same location on his M30 race motor. Both of us use VDO gauges and have had excellent results with the location. At least, haven't had any reason to relocate it. Working great and the motors are run, 'enthusiastically'.

Our pressure senders are in different spots, a PO on my car custom mounted the oil pressure sender to the side of the oil filter case, seems also to be working great. i have no reason to think otherwise.

All in all, both sender locations are working quite well for me.

HTH,
-shanon
 
Oil temp

Dequincey,

Many do use the oil plug and even VDO sells one.

So here's the debate:

1) Oil pan- in practice and for the reasons you stated, oil temps are lower as much as 30 degrees since you also have factors you didn't consider.

2) What did the factory do?- engines used the oil filter bracket as Shanon reports, other brackets ( 6s upright), and various other ways when oil coolers were mounted, etc.

3. A machined aluminum block or T of sorts which allows the required length of the probe for full emmersion with the opposite side for the other normal sender with a banjo bolt for oil flow that screws into the original location. ( Most common now and available at many racer suppliers) Clearance would have to be considered.

Realizing that this is a serious question for some for obvious reasons, the correct answer is 3 preferably, or 2. The temperature will be highest at the head and block area. ( I know that many do use the pan. But we're discussing optimum.)

What you're trying to do is determine if the maximum safe temperature of the oil is exceeding the water temperature and a correction must be made- usually a cooler or second cooler is the norm. Since mechanical guages have been abandoned for thermister types with some resultant delay, by the time you reach critical oil temps something has probably already happened.

As a guide, BMWs ( M3-M5, etc.) reportedly run about 180. Many with the pan sensor report only seeing 150 despite sitting for long periods with temps well above what you experience. Hot is in the 220-230 range, 280 might be for a racer that just pushed it on a very hot day.

I know you've got every justification to be overly cautious. VDO sells a warning sensor that forced induction guys use that might be useful.

I hope this is helpful.... and as I said the debate goes on.
 
possible alternative location

I agree 100% with the information you gave me, also you have given me a surprise with the figure of the difference of temperature between the head and the pan, (30º (i assume ºF))

that was one of my key questions, because I had no knowledge of that value and nowhere to find it

you pointed out also a critical isssue, the delay in the meassurement (I have heard something of 3minutes delay), that is too much !, as you said, by that moment the engine would have been damaged and you will notice very late

here is my other possible location, in the oil filter bracket, but I am worried about the thickness of the aluminum wall in which I will have to thread the sensor, anyone knows a practice example of this location ?

regards

sensortempaceite.jpg
 
I would tackle this in two ways.
First find out how high the oil temperatures are at several different spots on the engine. Then, where they are the highest. How does the temperature change from that hottest spot. Does it drop dramatically , stay the same or rise?
once i know that i would get several digital gauges with feeler and install them right into the oil stream somehow. maybe under the valve cover? anyway, i would try to get as close to the 'action' as possible.
It can't be really accurate if you measure with sensors that need a long time to register. You want to see any deviations instantly.

Then i would have a close look at the oil i would use. At which temperature and which pressure does the oil film break? Different oils have different characteristics.

You could have several sensors registering instantly what temperature is where in the engine.
Or you could have one sensor somewhere along the line and predict what temperature is in all the other locations. Just a matter as how far you want to go with this. And the possible gain you can achieve.
 
Years ago, on my '72 euro 2002, I add vdo's for water temp, oil pressure & temp, voltage ( I used the center console lowering the stereo and putting a hiding cover over it) sure wish I had pic's!

IIRC, it had combination sensor for oil P & T that went into the original sender location; I duplexed the P for the original idiot light. Not sure if that was the best location for the temp discussion, but thought that I would give some 25 year old information.

Jon
 
JhwShark said:
Years ago, on my '72 euro 2002, I add vdo's for water temp, oil pressure & temp, voltage ( I used the center console lowering the stereo and putting a hiding cover over it) sure wish I had pic's!

IIRC, it had combination sensor for oil P & T that went into the original sender location; I duplexed the P for the original idiot light. Not sure if that was the best location for the temp discussion, but thought that I would give some 25 year old information.

Jon
Click to expand...


just the same as me, here is the beginning of the installation:


2uhpz60.jpg



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Oil housing

Usually tapped on the side towards the firewall. There were different ones though as some had a untapped boss (casting). You might consider changing, perhaps to a spin on with oil line tap(s).

I would pm Shanon for a pic or perhaps someone else can help as well.

Usually the temps are a secondary issue.

1. Viscosity
2. Flow
3. Clearances
 
deQuincey,
Exactly what I did, though I used a shorter height, and made a second solid for the lower segment. Coverd both with black leather to match interior.
 
Here ya go!

oil pressure sender mounted to the side of oil filter canister:

oilpressuresendercopy.jpg


VDO gauge layout:

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HTH,
-shanon
 
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hi shanon

very neat assembly, but, isn´t it difficult ?, how had you install the thread in the oil filter canister ?

here is my option:
33jso6o.jpg


in this photo you can see the original point for original oil-pressure sensor, it is in a M12x1,5 thread, my intention is to maintain the original warning light in the instrument panel, so I will use an adapter (see the following pic):

it has a central hollow bolt M12x1,5 that goes into the cylinder head, and two lateral threads M12x1,5,
el8sqc.jpg


this will allow me to install in the mentioned point of the cylinder head two sensors: the original warning presure sensor, and the new pressure measurement sensor together

the one that is missing is the temperature sensor, that will go in the oil drain hole screw as pictured
240920101158.jpg
 
I use the original pressor warning light mount at the rear of the head, split with a T junction to provide temp and pressure. The warning light still functions as well. This provides sufficient feedback for spirited road and rally use.

Sender.jpg
 
new place for oil temp sender

I think, I have solved my problem of oil temp sender positioning

the previous conclusion was that the oil drain hole screw was not the best for temp sender, due to not being the maximum oil temp place

I bought a second hand oil filter complete assembly (it is as complete as the old dirty filter is included !:-D), in order to do some trials to install a sender somewhere

then I found a solution, because I found a closed hole (12mm diameter and 10mm depth) that can be the perfect place for the mentioned sensor
101020101209.jpg


of course first I will have to drill a passing hole, then built a thread on it, but it seems a good choice

does anyone knew this ? any problem for that solution ?
 
problem solved

considering the good advices regarding the best possible position for oil temp sender (that discard the oil drain screw), I have made a little mechanic job to install it in the oil fliter support, see pics:

this is the standard aspect of the oil fliter support

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Esta imagen ha sido redimensionada. Haz click aquí para ver la imagen completa. El tamaño original es 1024x768 tamaño 168KB.
101020101209.jpg

sensor is M10x1,5, so an adapter is needed to use it in the 12mm diameter existing hole

an adapter M14x1,5 versus M10x1,5 is used

1510901217.jpg


see the use of the adapter, exterior thread M14x1,5
151020101218.jpg

sensor body inside oil channel towards inside engine
151020101221.jpg

pre assembly
151020101222.jpg


as the thread adapter has been fixed with loctite thread adhesive, i am worried about electric continuity, so a by-pass from a fixing screw was done, using the electric plug also as a washer for the sensor (this function is critical, but I take the advantage that the plug is made of copper as this kind of washers must be)
151020101223.jpg


I am happy with this, so If it can be useful for anyone, I will be happier then :-D

if anything is not well explained do not hesitate to ask, I will do my best

regards
 
here we go again, now the instruments in the dash

hi, summer gives us a little more time for our hobbies, so the instrument issue comes again

i have prepared a shorter panel (i refused the installation of a radio, who needs music when you have a big6-in-line under the hood?), to hold the clocks:

it include: volt., water temp., oil temp., oil pressure
070220072515.jpg


[/IMG]
this is a wood panel that can be painted to match the dash wood color
070220072510.jpg

the other possibility is to cover it with black leather
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i think that black is better because:
the ring of the clocks is chromed, and that way this new four clocks are better integrated in the whole dash

but, what do you think ?? wood or black ??

regards
 
Black leather or matching vinyl or metal with textured black paint is my vote. What is in place of your front 2 electric window switches?
 
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Stevehose said:
Black leather or matching vinyl or metal with textured black paint is my vote.
thanks, yeah, probably that will be the best one !

What is in place of your front 2 electric window switches?
those are the air cond. switches/regulators, the left one gives the three different power stages of the air cond unit fan, and the right one switches on/off the Air cond and also has the sender to regulate it

does anyone have a similar arrangement ?
Click to expand...
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