Club 80-90 Forums

bigbadbob76 wrote: Maybe just don't treat them as accurate instruments, but more of an indication of abnormal conditions.
You'll soon get to know what's normal for your gauge and sender location.
I'm thinking of putting an M14x1.5 to M10x1 adapter in my sump plug location and sticking a cheap gauge sender in there, yes it will read lower than true oil temp and not respond quickly due to the sump sinking heat but in your own words "who cares".

I think you're right about using the gauge as an indicator of abnormal conditions. I have a sender in the sump plug location:



And I also have a Mocal thermostatic sandwich plate which directs my oil through a big front-mounted cooler.



The sandwich plate thermostat is set to 80 degrees, and my oil temperature gauge reads a steady 80 degrees ALL the time. Is that coincidence, i.e. a number of inaccuracies cancelling each other out by luck? Maybe, but I don't care - when it reads 80 on the gauge it means all is well.

As a nice side effect, I've noticed my water temperature needle is a lot more stable than it used to be - sits in the middle over the LED all the time - and I have the feeling that cooling the oil separately has taken a lot of the load off the water cooling circuit.

Oh, and I have an oil pressure gauge next to the oil temperature gauge, fed from the pushrod sender location, and as a consequence of the stable and moderate oil temperature the pressure is always nice and high.

CJH wrote: my oil temperature gauge reads a steady 80 degrees ALL the time.

even when cold?
summit wrong with it

I have read that 80 degrrees to too cold and does not allow moisture and nasties to burn off.
any comment on this?

CJH wrote:
And I also have a Mocal thermostatic sandwich plate which directs my oil through a big front-mounted cooler.

As a nice side effect, I've noticed my water temperature needle is a lot more stable than it used to be - sits in the middle over the LED all the time - and I have the feeling that cooling the oil separately has taken a lot of the load off the water cooling circuit.

I didn't know what you had done, honest, I agree on the oil circuit reducing load on the water circuit too. Proper job.

itchyfeet wrote:I have read that 80 degrrees to too cold and does not allow moisture and nasties to burn off.
any comment on this?

I'm no expert on this, but I have read that it doesn't need to be at 100 degrees to 'boil' off any moisture - 80 degrees will promote fairly rapid evaporation. Imagine, say, a baking tray held at 80 degrees with a film of water on top - how long would it take for the water to evaporate? I read a nice post somewhere by someone who explained the physics - probably won't be able to find it again though.

Anyway, who says it's at 80 degrees throughout the engine - I thought that's what this thread was exploring/explaining. 80 degrees on my gauge MAY mean that it's close to 80 degrees at the sump sender, but what temperature is it at elsewhere in the engine?

itchyfeet wrote:I have read that 80 degrrees to too cold and does not allow moisture and nasties to burn off.
any comment on this?

He's talking oil temp, water temp is higher as he said the gauge is bang in the centre. Separate thermostats achieve whatever you want.

CJH wrote:I read a nice post somewhere by someone who explained the physics - probably won't be able to find it again though.

Found it!

937carrera wrote:

itchyfeet wrote:I have read that 80 degrrees to too cold and does not allow moisture and nasties to burn off.
any comment on this?

He's talking oil temp, water temp is higher as he said the gauge is bang in the centre. Separate thermostats achieve whatever you want.

yes I know
80degrees oil temp is lower than the boiling point of water so condensation in your sump does not boil off

itchyfeet wrote: yes I know
80degrees oil temp is lower than the boiling point of water so condensation in your sump does not boil off

Doesn't need to boil off - just needs to evaporate. Posts 4 and 5 on page 2 of the thread I linked.

CJH wrote:I think you're right about using the gauge as an indicator of abnormal conditions. I have a sender in the sump plug location......
And I also have a Mocal thermostatic sandwich plate

Now you've got me thinking a sender sandwich plate (rather than a cooler sandwich plate) would be a good place to put my BOD pressure switch (mines blanked off ) and oil temp sender.
less heat sinking and the oil is being circulated through there by the pump.

CJH wrote:

bigbadbob76 wrote: Maybe just don't treat them as accurate instruments, but more of an indication of abnormal conditions.
You'll soon get to know what's normal for your gauge and sender location.
I'm thinking of putting an M14x1.5 to M10x1 adapter in my sump plug location and sticking a cheap gauge sender in there, yes it will read lower than true oil temp and not respond quickly due to the sump sinking heat but in your own words "who cares".

I think you're right about using the gauge as an indicator of abnormal conditions. I have a sender in the sump plug location:



And I also have a Mocal thermostatic sandwich plate which directs my oil through a big front-mounted cooler.



The sandwich plate thermostat is set to 80 degrees, and my oil temperature gauge reads a steady 80 degrees ALL the time. Is that coincidence, i.e. a number of inaccuracies cancelling each other out by luck? Maybe, but I don't care - when it reads 80 on the gauge it means all is well.

As a nice side effect, I've noticed my water temperature needle is a lot more stable than it used to be - sits in the middle over the LED all the time - and I have the feeling that cooling the oil separately has taken a lot of the load off the water cooling circuit.

Oh, and I have an oil pressure gauge next to the oil temperature gauge, fed from the pushrod sender location, and as a consequence of the stable and moderate oil temperature the pressure is always nice and high.

Do you have standard oil pump and what size pipes to the front rad, I have noticed that my oil pressure fluctuates with the oil cooler in the passenger side vent bottom ( some journeys better than others)it would be nice to make the efficiency more stable by moving to the front

Yes, standard oil cooler. I was worried that I might need a bigger one, but I had a very strong steer on here that it wasn't needed - might even do more harm as it would heat the oil up more. I'm grateful for that steer, and the proof that it wasn't needed, as far as I'm concerned, is my nice high oil pressure.

The pipe I used is this one I think - half inch internal diameter, 17mm external diameter. Possibly overkill, but it's good strong stuff. Very difficult to route neatly, and absolutely no twist to it - definitely needs a joint in the middle somewhere if it's got 90 degree bends at each end, as the middle joint is the only way to get the orientation of the bends right at each end.



I say "I think" because I can't remember for sure - I looked back over the part of my engine build thread where I discussed this (here), and even then I couldn't remember - had to deduce from the external diameter.

CJH wrote:Yes, standard oil cooler.

Pump! I meant pump!

CJH wrote: The pipe I used is this one I think - half inch internal diameter, 17mm external diameter.

Interesting, I'm used to seeing larger than that, 15-17mm ID, probably to avoid pressure drop over a long run, but 1/2" obviously works well enough. Empirical engineering

Yeah I got lucky - that hose was too expensive to do twice. I don't really know how to size the pipe properly by other means - my fluid mechanics isn't up to it - but a few things that spring to mind:

- Oil at 80 degrees is pretty runny
- The greater resistance in this part of the oil circuit is most likely the matrix itself
- The pressure required to push the oil through the engine oilways will be higher still

So gut feeling says that a nice smooth straight pipe with half inch ID isn't going to be much of a bottleneck.