Oil Cooler Too Eager, Faulty Thermostat Or Incorrect Temp Sensor Location?

[plaything]

HI mate,

what an incredible similar issue that I now have.

Just quickly: Honda S2000.

I also am using the same Mocal sandwich plate you are using; high temp thermo allowing full flow at 93C/200F, in addition to Earls 19row cooler with earls fittings and lines!

Like you I have Defi gauges and was initially tapping at the sandwich plate, and now currently tapping via a sump plug adapter from SARD at the sump.

Previously oil temp was 85-95C for regular street driving, like I mentioned tapped at the sandwich plate

Now with the cooler installed, extra 500ml of engine oil, my oil temp readings are around 70-80C in Sydney's weather today.

I have a feeling that like many many posts across the internet reflecting a difference between oil temp readings at the sump, compared to the sandwich plate.

I tested my sandwich plate from Mocal, and it is indeed the correct wax pellet as I can see it completely shutting off at around 96C, it begins to move around 92-93C. I also kept an eye on my gauge today, and I believe the thermostat never completely closed today, re-routing all oil to the cooler, and back. The reasoning behind this is I never seen any dramatic drop in oil temp....

I can see you also ordered that pressure gauge adapter to fit the defi sensor, please note the fitting is 1/8NPT, and just a quick FYI that the defi sensor is 1/8PT (otherwise known as BSP Tapered or BSPT) and trust me, there is no guage fitting that has a thread to accept 1/8PT ... I do have the special fitting where I found the only place worldwide to selll it, you will need this to convert the threads over to fit the defi sensor, not to mention, this fitting will also act as a spacer as the defi oil temp sensor is too long for the -10an fitting! I was going to initially do this setup too, but I hadnt exactly seen any proven results that it would read correct and consistent data, and it was too expensive a gamble to take, as I would have to order two brand new hoses, and have two pressure gauge fittings being useless.

Effectively with my car's data, there is a 15C difference between before and after the oil cooler installation. I understand by adding another 500ml (10% increase of oil capacity), plus the fact that there is a percentage of oil that flows through the sandwich plate <93C thus some portion of oil being cooled, I cannot fathom these two additional variables can equate to a 15C difference, possibly a 5-10C difference. I do believe the fact that I am now reading data at a different location fills the gap between 5-10C to make up the total difference of 15C mentioned above...

I also want to note, that I have only found Greddy and SARD to offer a sump plug adapter fitting to suit Defi gauges, HOWEVER I am a little concerned that I screw in the Defi sensor into the Sard adapter, it lies flush with the end of the adapter, and not protruding as I would have hoped. I do believe this may not be an issue, as with the theory of HEAT TRANSFER, the sensor will eventually obtain a consistent temperature reading in the sump....

TL, DR:

- I also experience same issue you are

- Our oil cooler installation is basically identical

- I believe the reasons we both see temp drop is a combination of oil cooler installation, increase in oil capacity, different location of sensor being housed.

I've also PM'd you too!

[plaything]

just wanted to elaborate that tested my sandwich plate this morning with the kettle, a pot, and another manual thermonter. The thermostat starts to closed around 93, and at 95 its completely shut. and bringing the temp of the water down <93, the thrmostat begins to open again.

Additionally, I will get some perspex or junk metal, and use it as a block off plate for the street, and monitor temps like that.

[V28VX37]

HI mate,

what an incredible similar issue that I now have.

Just quickly: Honda S2000.

I also am using the same Mocal sandwich plate you are using; high temp thermo allowing full flow at 93C/200F, in addition to Earls 19row cooler with earls fittings and lines!

Like you I have Defi gauges and was initially tapping at the sandwich plate, and now currently tapping via a sump plug adapter from SARD at the sump.

Previously oil temp was 85-95C for regular street driving, like I mentioned tapped at the sandwich plate

Now with the cooler installed, extra 500ml of engine oil, my oil temp readings are around 70-80C in Sydney's weather today.

I have a feeling that like many many posts across the internet reflecting a difference between oil temp readings at the sump, compared to the sandwich plate.

I tested my sandwich plate from Mocal, and it is indeed the correct wax pellet as I can see it completely shutting off at around 96C, it begins to move around 92-93C. I also kept an eye on my gauge today, and I believe the thermostat never completely closed today, re-routing all oil to the cooler, and back. The reasoning behind this is I never seen any dramatic drop in oil temp....

I can see you also ordered that pressure gauge adapter to fit the defi sensor, please note the fitting is 1/8NPT, and just a quick FYI that the defi sensor is 1/8PT (otherwise known as BSP Tapered or BSPT) and trust me, there is no guage fitting that has a thread to accept 1/8PT ... I do have the special fitting where I found the only place worldwide to selll it, you will need this to convert the threads over to fit the defi sensor, not to mention, this fitting will also act as a spacer as the defi oil temp sensor is too long for the -10an fitting! I was going to initially do this setup too, but I hadnt exactly seen any proven results that it would read correct and consistent data, and it was too expensive a gamble to take, as I would have to order two brand new hoses, and have two pressure gauge fittings being useless.

Effectively with my car's data, there is a 15C difference between before and after the oil cooler installation. I understand by adding another 500ml (10% increase of oil capacity), plus the fact that there is a percentage of oil that flows through the sandwich plate <93C thus some portion of oil being cooled, I cannot fathom these two additional variables can equate to a 15C difference, possibly a 5-10C difference. I do believe the fact that I am now reading data at a different location fills the gap between 5-10C to make up the total difference of 15C mentioned above...

I also want to note, that I have only found Greddy and SARD to offer a sump plug adapter fitting to suit Defi gauges, HOWEVER I am a little concerned that I screw in the Defi sensor into the Sard adapter, it lies flush with the end of the adapter, and not protruding as I would have hoped. I do believe this may not be an issue, as with the theory of HEAT TRANSFER, the sensor will eventually obtain a consistent temperature reading in the sump....

TL, DR:

- I also experience same issue you are

- Our oil cooler installation is basically identical

- I believe the reasons we both see temp drop is a combination of oil cooler installation, increase in oil capacity, different location of sensor being housed.

I've also PM'd you too!

just wanted to elaborate that tested my sandwich plate this morning with the kettle, a pot, and another manual thermonter. The thermostat starts to closed around 93, and at 95 its completely shut. and bringing the temp of the water down <93, the thrmostat begins to open again.

Additionally, I will get some perspex or junk metal, and use it as a block off plate for the street, and monitor temps like that.

Awesome replies, thanks mate! The plot thickens...

Ok first of all, I have uploaded photos of the various parts here for people to have a look: https://www.flickr.com/photos/v28vx37/albums/72157661712678623

Including my original sandwich plate (non Mocal)

and the Mocal service kit with the replacement 92C wax pellet etc:

I was this close to ordering the Greddy GREX plate last week but Garage 7 is all out and apparently they're like hen's teeth in Oz now...

...

With the temps, we have already concluded that my current temp reading is incorrect because the sensor is not in direct oil flow. Before I write off the Mocal sandwich plate I want to make sure that the sensor is as close to previous positioning as possible, to get some more reliable temp comparisons.

I think a lot of the temp 'drop' I'm currently seeing is less about the cooler and more about the temp sensor positioning. This would be supported by the fact that my water temps are quite similar to before and not significantly less. I'm still running the factory oil-water unit that is meant to equalise the two temps.

...

Speaking to MSCN, the local Mocal distributor, I learned a couple of things:

• In a lot of cases people install these sandwich plates into cars that whilst are stated street&track are in fact mostly track, and overcooling is not an issue for them. Basically what they were saying is that the thermostat operation is not as 'clear-cut' as one might hope for a street car.
• Also they said that the cooling circuit is never fully shut, even at <thermostat temps. This makes me think that I should get a reasonably reliable temp measurement from the outgoing (hot) line to the oil cooler, even if only a fraction of oil is going into the circuit.

As mentioned I've also got a full Mocal service kit with a new 92degree thermostat to fully rule out the possibility of a faulty unit. In case anyone's looking this is about AU$50 from Speedflow UK landed in Melbourne.

...

With the fittings, the Defi 1/8PT is a complete pain, they're impossible to find. Because of this I'm pretty sure what the workshop did is to use a bit of teflon 'cement' and screw the temp sensor into a 1/8NPT brass fitting. From my understanding the setup was similar in the fitting with my previous sandwich plate, so whilst it's not a 100% fit it does seem to work.

When I ordered my Defi parts from RHDJapan I also ordered a SARD oil block adapter PT1/8 to M14x1.5, and a matching plug for it. I was originally planning on using it as a bung for the exhaust temp sensor.

I played around with the parts just then and I can easily screw the Defi oil pressure sensor (with PT1/8 thread) into the AN10 fitting (with NPT1/8 thread). Yes it's not 'tight' but fairly close:

Now what's really really strange is that I can't screw the same sensor into the SARD adapter that's meant to be the same thread?! It only goes in a mm or two:

This whole PT/NPT/BSP/BSPT business is a disaster

I see what you mean about the Defi oil temp sensor length too, I'll probably need to run an NPT1/8 spacer.

Where did you find the PT-NPT adapter by the way, are they based in Oz?

Also can anyone confirm if the OEM oil pressure sensor is 1/8PT or something else?

...

In summary, here's the current plan:

1. Refresh the Mocal sandwich plate with the service kit inc. new thermostat
2. Move the Defi oil temp sensor to AN10 fitting (with a spacer?) running off the outlet (hot) line of the Mocal
3. Install the Defi oil pressure sensor in the OEM location
4. Pray that it all works?!

Any other ideas are welcome!!

Ps. I recently found this cool writeup on an S2K oil cooler installation in case it's of any use: https://robrobinette.com/S2000OilCooler.htm

[Ben C34]

Oem is 1/8 bsp. Which is tapered. So also called 1/8 bspt never heard it called pt before.

[plaything]

HI Mate,

Yes Rob's blog is very informative for the trakc enthusiast, although it is focused on RX7/S2000.

Garage7 is f**king useless, although I just emailed them, its a poor result that I received nothing. Anyways, the Grex sandwich plate is pretty decent, in fact from my research of best place to tap sensors in conjnction with an oil cooler, the greddy sandwich plate is the absolute best design. Its only drawback is the thermostat begins to completely shut at a low 72C. As my car, and I believe your car is also a street car, we do not want sub optimal tempertures..... I reckon the Greddy tech's decided to opt for a low temp thermostat as they would have built this sandwich place around the end user uing their greddy turbo and ecu and tiny 10row oil cooler, in other words, they are expecting the end user to have big HP, and thus utilising a small oil cooler that is universal to all makes and models, and then having the oil cooler working earlier compared to the vast majority of big name sandwich plates on offer!

Yes as others have mentioned, I do believe your current location of tapping where the oem oil pressure sensor sits to act as an area to read oil temp isnt the ideal location. Especially with the brass T fitting applied.

My water temp like yours, IS also the same before and after oil cooler installation. From my experience the OEM heat exchanger / water:oil factory cooler only works well to warm up cold oil with relatively warm water during startup/warm up. But the opposite doesnt work in the real world.

RE MOCAL; I spent a few nights 6 months ago calling the tech's over in the UK asking questions back and fourth. Ive been busy with a newborn and work last few months, hence the slow build on the oil cooler! But for some reason I have the figure of 5-10% in my head in terms of oil flow through the oil cooler circuit when < thermostat fully shut temp. It looks like from our two installtions, that this is not correct, where there is a much higher percentage when 10% of flow when < thermostat fully shut temp. I have a spare brand new mocal sandwich plate for my mate which is also the high temp option which I played around with. By going by 100% of flow when the thermostat fully shuts, when temp is < 93C, it looks like the thermostat allows around 50% flow.... THis is just an estimate.. but its around halfway there! It would be ideal to run a temp sensor before (1) oil cooler, after (2) oil cooler, and sump (3) but for me, this is just a weekender and as much as possilble track car.. Too expensive having 3 gauges and 3 sensors.

I went through a headf**k as no one could confirm the thread metric/pitch on the oem oil pressure sensor etc, long story short, It was a perfect fit where I screwed in my defi oil pressure sensor into the oem oil pressure location. Please note this is on my Honda S2000, so it might be different on your RB25 block! If I were you, I'd strongly research and find out what the thread is, possibly best option is to just take the oem pressure sensor to bunnings, and test to see what fits! Be sure to use some threadlock/tape etc, but 100% get rid of that weak brass t fitting. Your engine especially at high RPM will have vibrations, and the weakest links suffer, in your case it will be that brass fitting. Over time that will crack at the threads being another headache.GET RID OF IT!

NPT and PT are same same but different, i guess u can get away away when using threadlock. As the SARD unit is a universal fitting, ie they didnt design it with defi in mind, I also found the fitting not as ideal. Not sure if I mentioned initially, but as I am tapping via the sump, i screw in the sard adapter to the sump, and then on the female side screw in the defi oil temp sensor. THis goes in about 50% of the threads, and locks out. hope this info helps re oil pressure snesor and the adapter from sard..

I got the fitting from mcmaster-carr. I have a spare one which I can post down to you. It is the part you require, male is 1/8NPT, female is 1/8P. From memory the defi temp sensot from the tip to the last thread is 30mm long, and this space is 20mm long, so this will allow you to both obtain clearance of the sensor in the fitting, and convert the correct threads across on either end. from memory it was $30USD for the part, plus $25USD shipping (what a f**king joke)!!! I'll obviously sell it much less than that!

In summary, here's the current plan:

1. Refresh the Mocal sandwich plate with the service kit inc. new thermostat - Before doing this, do as I also did and test the sandwich plate by boiling some water, put the sandwich plate and boiling water in a pot, I also turned on stove to maintain heat. Put a kitchen or whatever thermomnter in the water to get a second reading... you should seee the thermostat begin to close around 93C, and fully shut moments later. Also test by cooling the water and watch the reverse!
2. Move the Defi oil temp sensor to AN10 fitting (with a spacer?) running off the outlet (hot) line of the Mocal - Since you have ordered the gauge -10an fitting, might as well give this a try. be sure to buy the fitting off me,or directly from mcmaster-carr first though!
3. Install the Defi oil pressure sensor in the OEM location - as long as the metrics line up, screw it right in. Otherwise the best setup is IMO: lets just assume this first:

oil pressure thread/pitch/metric on the rb25 block is 1/8NPT

defi oil pressure sensor is 1/8PT

I would get an adapater that is 1/8NPT male, and -3an female, -3an braided hose, a second adapter that is -3an male and 1/8PT female.

Connect all up as above so you have the hose with correct fitting to the block, and at the end you have defi oil pressure snesor. you then mount thedefi pressure snesor somewhere in your engine bay. BY USING the line rather than a t fitting, the line absorbs the vibrations, but wont crack since it moves etc.

[plaything]

Oem is 1/8 bsp. Which is tapered. So also called 1/8 bspt never heard it called pt before.

well you are in luck OP! BSP is a term I f**king hate, because it can be either tapered or parallel. the Yanks have adopted BSP for fittings that are BSP (Parallel).... the japs use BSPT (tapered) but call it PT.... since it is parallel, either a BSPP or BSPT fitting will work. You may find there could be a few threads leftover onthe defi sensor since it is a tapered fitting, it going to expand and seal. Regardless I would use some threadlock sealant again!

At least that is confirmed, and its just now to focus on the oil temp!!!!!

[plaything]

Towards end of Feb once I get my car back from a respray, I will be removing my oil cooler sandwich plate, reinstalling the greddy sandwich plate and will simultaneously compare oil temps at both the sump and sandwich plate region. I was going to do this prior to oil cooler, but wanted to get it done before going into the shop etc.

By doing the above, I will have no variables to consider, becuse the conditions will be exactly the same where the only difference is just the different location of sensors!

[GTSBoy]

There is absolutely nothing confusing about NPT and BSP.

The N in NPT stands for National. National Pipe Thread. It is the standard USA pipe thread.

The B in BSP stands for British. British Standard Pipe. It is (obviously) the British standard, and is therefore also fairly common across the rest of the world. Wherever the Poms got to before the Americans it is quite likely that BSP is the standard. The main exceptions are places like the Middle East where the Poms were there first, but the US oil and gas industry has since had more influence and NPT also has good saturation.

Australia pretty much does everything with BSP. There is of course plenty of NPT around too, because Americans are also everywhere.

1/2" BSP and 1/2" NPT are NOT the same thread, but they are close enough to the same within tolerances that you can put one into the other and get a decent seal. All other sizes pretty much won't go together or will take a couple of threads and seal with enough tape, but are not recommended practice to put together. If it does not wind in all the way (parallel) or at least 4 or 5 threads (tapered) then it is not the same thread or is damaged.

Edited January 28, 2016 by GTSBoy

[plaything]

Nice post... Cannot see your relevance to our issue though.

Thanks google searcher.

[Ben C34]

There are people who know that information without having to use Google

I would consider the post relevant to this thread.

[XGTRX]

There are people who know that information without having to use Google

I would consider the post relevant to this thread.

Same people that often offer free advice to people that are willing to learn

[V28VX37]

Ok this is turning out to be a nice little challenge.

As plaything rightly pointed out above the AN10 fitting won't have enough clearance inside for the Defi temp probe. The inner diameter is roughly 12mm.

I've included the Defi specs below, the length of the probe insert is 28mm including the threaded part, so about 18mm without. It's too long.

He's sending me the McMaster-Carr 1/8PT to 1/8NPT adapter (P/N 4092K26), however we've just realised that the hole in the adapter is too small for the sensor to fit through The sensor diameter is 7mm in the thicker part and 5.5mm at the tip as per the Defi specs.

I've found the McMaster-Carr drawings ( http://www.mcmaster.com/#4092k26/=10x1ec7 ), which don't specify the inner diameter but given the size of the 1/8NPT end I'd estimate the hole to be about 5mm. The adapter is made of type 316 stainless steel.

Finally, the question: The material thickness in the adapter at the male 1/8NPT end is about 2mm. So if I drill the diameter to be 7mm up from 5mm, it would leave about 1mm of material. Will this weaken the adapter too much and risk an oil leak?

Thanks again guys. What a puzzle.

...

Defi sensor specs, temp probe is second last

McMaster-Carr 1/8PT to 1/8NPT adapter

AN10 fitting with sensor port

[GTSBoy]

The bottom of the threads on the male 1/8 NPT section should be about 8.6mm (diameter). If you bore the centre to 7mm then you will have ~0.8mm wall thickness. I would not think that thick enough for something that has 6+ bar of pressure inside and is carrying a (small) mechanical load and is subject to gross vibration.

If it were me, I would put the Defi sensor in the vice and very carefully file down the 7mm section to as close to 6mm as I could - preferably <6mm if possible. Then bore the fitting to 6mm. That would leave closer to 1.5mm of wall thickness. Then pray it holds together. It's stainless, so it is probably going to be OK.

The smart move would probably be to drill the AN10 sensor port out to 1/4" and retap. Don't worry about the anodising - it's carrying oil. Then use a 1/4" version of the 1/8" adapter - or whatever combination of a similar adapter or spacer + an adapter bush. In fact, if you drill and tap the sensor port, then you can probably stick with all BSP threads to suit the sensor and not have to worry about adapting from NPT to BSP. Then you also don't have to bore out the skinny 1.8" stuff and so on and yada yada.

Edited January 31, 2016 by GTSBoy

[V28VX37]

The bottom of the threads on the male 1/8 NPT section should be about 8.6mm (diameter). If you bore the centre to 7mm then you will have ~0.8mm wall thickness. I would not think that thick enough for something that has 6+ bar of pressure inside and is carrying a (small) mechanical load and is subject to gross vibration.

If it were me, I would put the Defi sensor in the vice and very carefully file down the 7mm section to as close to 6mm as I could - preferably <6mm if possible. Then bore the fitting to 6mm. That would leave closer to 1.5mm of wall thickness. Then pray it holds together. It's stainless, so it is probably going to be OK.

The smart move would probably be to drill the AN10 sensor port out to 1/4" and retap. Don't worry about the anodising - it's carrying oil. Then use a 1/4" version of the 1/8" adapter - or whatever combination of a similar adapter or spacer + an adapter bush. In fact, if you drill and tap the sensor port, then you can probably stick with all BSP threads to suit the sensor and not have to worry about adapting from NPT to BSP. Then you also don't have to bore out the skinny 1.8" stuff and so on and yada yada.

Thanks once again GTSBoy, really good advice.

I like your idea of retapping the AN10 fitting. Unfortunately there's only about 2mm of material - minus thread depth - on the front and rear side of the port. You can kind of see this in the photo above. I'm afraid that's not enough to make the port any larger, so it's basically the same issue as with the adapter.

...

Another option could be running an AN10 T piece with an AN10-to-1/8PT adapter (who know if one exists) but that's moving the sensor out of the direct oil flow:

This is getting way complicated. I can't believe the Mocal doesn't include a port for sensor, seems like a total oversight - who would run an oil cooler without a temp gauge?

[V28VX37]

I reckon we'll try to stick the current brass I piece into the 1/8NPT on side of the AN10 fitting. Fingers crossed.

[Ben C34]

Here's a wacky option.

Tee piece where the turbo oil feed is. Assuming g you are using a braided line there, not a banjo.

[V28VX37]

Here's a wacky option.

Tee piece where the turbo oil feed is. Assuming g you are using a braided line there, not a banjo.

Now that's pretty cool. Yes it's a braided line, the one that came with my HyperGear ATR43SS2. I have no clue how the oil flows inside the block, do you reckon that'd be roughly the same temp as the oil filter outlet?

Another option some have done is to drill & tap into the base/bracket that holds the factory oil/water cooler (or whatever they call it). Feels a bit drastic.

[Ben C34]

The oil splits off and goes to where it has to go.

It doesn't go through a bearing then on the way to the head or turb etc.

[V28VX37]

I was just testing the thermostatic wax pellet and finally got it moving in boiling water, it's the 92C unit.

I then turned it upside down over the table and the pin popped out; I didn't realise it's not secured in any way.

I chucked it back in, I'm guessing no harm done?

You can see the pellet on the bottom left:

[V28VX37]

Got the car back today, oil temp sensor is now in the AN10 fitting off the hot outlet of the Mocal sandwich plate and all the moving parts of the plate have been replaced with the service kit. Prick of a job, a lot of stuffing around to get the sensor in place, I'll do a more detailed writeup soon.

Anyway on the way home in suburban traffic water temp was 80, oil was 80, ambient 20 – YAY!