TheSamba.com :: View topic - Temperature Control (electric)

Thu Apr 16, 2020 9:50 pm

kpbo wrote: I'm in the planning stages of a cooling/filtering system for my freshly rebuilt $yncro transaxle. Thanks to Sodo et al. for documenting all their efforts!

To stay on the topic of electronic control of the pump/fan... in my current plan I have a single 1/8 NPT port that I'd like to use for a temp gauge sender. This is a typical variable-resistance type sender made by VDO:

https://www.vdo-gauges.com/sensors/temperature-sen...1-9-1.html

I'd prefer to not have to drill another hole in the transaxle for a temp switch, so I'm wondering if I can make the sender serve double duty for temp gauge/switch.

My original thought was to find some type of gauge w/ a settable warning light function that I could co-opt to trigger the fan/pump relay. But I came up empty.

After a little digging I found this cheap little current sensing relay: https://www.aliexpress.com/item/12V-Digital-0-10A-...4.2.3lxc0g

The idea being that as the sender heats up (and resistance falls) the increase in current would, in principle, trigger the fan/pump relay. The neat thing about this relay is that (a) it's adjustable and (b) it can be programmed with a time delay/hysteresis function to minimize excessive switching...

My concerns/questions:
(1) would adding this switch in-line with the gauge sender mess up my gauge accuracy? i'm totally ignorant as to how these sensing relays work...
(2) would the range of currents in the sender wire be enough to trigger? from the info i found, it seems the resistance range in these sensors is nearly an order of magnitude in the expected temp range (e.g., assuming 14V: 1486 ohms @ 10 degC = ~7 mA -> 185 ohms @ 65 degC = 77 mA). Advertised accuracy is 10 mA... hmmm, maybe not sensitive enough?
(3) is this a whacky idea? other ideas welcomed (given the constraint of not wanting any more holes in my transaxle).

Thanks!

Lol years later but thought I’d throw this in the loop...
Stack st3510

http://www.stackltd.com/instruments_pro_control.html#

it’s a 52mm gauge that can fit in any gauge pod that has hi and low warnings with a 5v output on each that could trigger a relay for a fan, pump etc... tis a bit on the pricey side yes but very clean looking and hey whats another $250?? I’m planning to use one on my cooler install to trigger the pump on from the temp sensor I have in the transaxle. I believe I can set it to what ever temp I want... seems simple and straight forward, to me at least :)

Cheers

Fri Apr 17, 2020 6:22 pm

Here is the promised update on the filter check on my tranny.

I installed a fresh tranny from AA at the same time I converted to a '07 2.5 Suby. I have been running Amsoil 80-140 gear oil. I did an oil change after 15k miles and saw very little metal on the magnetic drain plug.

After another 10k I installed my cooling/filtering system and fresh Amsoil. See previous posts for details.

SODO convinced me to check my filters. So last week I pulled the Canton and Magnom filters. At this point I have 8k miles on it since the filter installation. I drained both filters and washed the Canton filter. There was a small amount of iron based super fine metal particles that had passed through the 8 micron Canton filter and were caught in the mini Magnom. See the picture below. The key is for size reference as it is a small filter.

There was almost no sediment in the oil I drained from the Canton and no appreciable particles that washed out of it when I agitated the paper filter in gas.

All in all I am very pleased with what I saw. I believe the combination of a fine particle filter, the Magnom, and the cooler will definitely prolong the life of my tranny.

Sat Apr 18, 2020 11:51 am

I think you forgot the pic ;)

Sat Apr 18, 2020 11:54 am

I think you forgot the pic ;)

Tue Jun 30, 2020 6:46 pm

As I wrap up my trans cooler installation I have a question about oil capacity. How much extra does one add to accommodate for the cooling setup. I put in 6qrts in total ( the recommended 5 qrts + 1) of swepco 202 but am wondering is that enough. Has anyone any tips? Below are some pics of my install.. was tricky and I took my time but am happy with the results..... let the slaying begin lol

Tue Jun 30, 2020 10:52 pm

I would think all you need to do is fill your transaxle as normal, run the pump a time or two and top up the trans. Not sure what type of pump you have but likely want to have oil at the pump suction before running it.

County Mayo! My wife’s family is from Castlebar. Beautiful part of the world.
Good luck to you.

Wed Jul 01, 2020 1:03 pm

Very clean set up! I just ordered the same Moroso clamps on eBay e few days ago :P

Same as above for finding out how much it needs....

Sun Aug 02, 2020 5:28 am

So, I've installed a system to filter and distribute oil, and recently I've been wondering...
How long would it take all these fancy pumps to completely drain your trans all over the interstate if you sprung a leak?
Would you have a clue?
Are you that confident that your system could never spring a leak?

I'm not betting my transaxle on it.

Has anyone here installed any sort of oil sensor that would tell you that you have oil?
I'm considering:
Float sensors for the fill hole - problem is oil level changes with inclination.

Or, an oil level sensor from a car oil pan, but not sure where it could be mounted

Seems like the temp sensors could do double duty - if the oil left, the temp should drop, but not sure how fast.

Or, a flow sensor for an oil line set up to alert with loss of flow.

Maybe a pressure switch in an oil line, but I'm not sure how much pressure is present in my lines.

Other ideas?

Sun Aug 02, 2020 6:41 am

You’ve described the Achilles heel of any remote cooler setup. Fortunately in a transaxle setup, it’s not under pressure or minimal at best. That removes the internal pressure related failures. Quality fittings and steel braid or reinforced hose is probably the best defense.

The most exposed area is the suction hose connected at the drain. The Syncro bracing should offer some protection.

Maybe google search flow meters. That might be a solution. Interested to see what you come up with.

Sun Aug 02, 2020 7:09 am

A way around that, although probably not easily feasible, would be to have the suction/intake hose about an 1" below the high mark. If a leak develops the level in the transmission would never really drop below that intake hose, maybe a bit more if you are doing some hard cornering. Just a thought.

Sun Aug 02, 2020 9:38 am

nmerrill wrote: So, I've installed a system to filter and distribute oil, and recently I've been wondering...
How long would it take all these fancy pumps to completely drain your trans all over the interstate if you sprung a leak?
Would you have a clue?
Are you that confident that your system could never spring a leak?

I'm not betting my transaxle on it.

Other ideas?

You could put a 3psi pressure switch between the pump and the filter.
Pretty easy to rig a warning buzzer that tells you if the pump is running but producing no pressure.
At this point of course your trans is already empty, but a trans can run quite a few miles empty before the gears dry up.
A trans in good condition can probably go a long ways, like 50 miles? 100 miles? All the way home?
I wouldn't knowingly run one 'empty', but its not like letting a journal bearing or pistons run dry.
Look how long they last grinding themselves to death on steel-infested oil - 80, 100,000 miles?
It will withstand more miles with zero damage cruising slow/easy, less miles if the pedal is mashed (towing a 2nd van up a grade?) :wink:
But a warning buzzer would notify you before any damage, and the circuit is simple.
Pretty sure this is towards 100% safety.
It would be safer than your coolant system warning in the sense that you could just drive slowly for a LONG way, if you had to.

A coolant system failure requires total shutdown, and much sooner.

Other idea would be to set the system to run the pump automatically ONLY if the temp exceeded ~~~ 160°F.
A well-built transaxle runs at about 145°F.
160°F is still (perhaps?) below the 'loose mainshaft bearing temp' of 180°F.
But nobody knows how much hold the case still has at 160°F.
That way the pump will hardly ever run, limiting your 'exposure' to the risk while on the highway.
And still prevent trans overheat.

Then you could just run the pump manually the last few miles to home to filter the oil.
The weddle pump for example at 2+gal/minute exchanges the entire 5 qts in ~30 seconds, it would not take long to clean up the oil like this.

I could not do this..... (just to minimize "the risk").
I'd just add appropriate guards and assess the safeties necessary.
And focus upon the clear-and-present-danger which is the over-engining of 90HP components that are already nearing end-of-life.
Which is not a "real" danger, but certainly a lifetime shortening event.

MarkWard wrote: You’ve described the Achilles heel of any remote cooler setup. Fortunately in a transaxle setup, it’s not under pressure or minimal at best.

My Weddle pump develops about 20 psi pushing heavy gear oil thru a 10 micron tractor filter when the oil is cold. When hot it runs at about 16-18psi. Barb fittings with rubber push-on oil hoses (no clamp) are _rated_ for 250psi with barb fittings. So regular rubber hoses with push-on fittings offer a 12:1 safety margin. This is likely a magnitude higher than the safety factor of your engine coolant system. Which, in general has proven to be a tolerable risk.

old_man wrote: A way around that, although probably not easily feasible, would be to have the suction/intake hose about an 1" below the high mark..

I think lots of people are doing this method, leaving a little in the bottom for the ring gear to sling around. Problem with this method is you don't get to suck the heavy metal from the floor drain of the trans 'immediately'. And if sucking from the bottom, you can manually run the pump 'cold' to suck off what has settled if you parked your van for a few weeks. Above the bottom has it's benefits and losses, its just less likely to filter out stuff at the earliest opportunity.

Everything has its trade-offs.

Knowing that an over-driven trans (that may have some 150,000 mile components etc) will produce more steel in the oil (no ifs, ands or buts ! ) my personal choice is to filter the oil from the bottom and keep it around 140°F.
That's my reasoning for MY trans.
You have to get comfortable with yours.
Nobody ever said over-engining would be simple. (oops some say that) :wink:

Sun Aug 02, 2020 9:54 am

16-18 psi. I would not have imagined the pressure to be that high. There are probably some vanagons running with that much engine oil pressure. A simple engine oil pressure switch and a warning light would be ample. Good to know.

Sun Aug 02, 2020 11:57 am

MarkWard wrote: 16-18 psi. I would not have imagined the pressure to be that high.

16-18psi is from shoving gear oil thru a Parker 10 micron tractor filter.
I was quite surprised that it wasn't higher.

I don't know what the back pressure would be "just from the hoses, fittings" etc.
I suspect a Weddle screen filter (140micron?) might have a lot less back-pressure than a 10 micron, but still some.

Some folks are using the 8 micron Canton fuel filter, I don't recall any posts stating the back-pressure & flow-rate thru that unit.
If anyone is doing the Canton 8micron, your psi & flowrate numbers will be appreciated by members.👍🏽👍🏽

I'll guess that with any system that has a bit of hoses and cooler, even with no filter you could have 3psi for the warning system.
But who wouldn't filter? :wink:

Sun Aug 02, 2020 2:01 pm

Pressure switch is a simple solution, but I wasn't aware of any low psi examples-

You mentioned a 3 psi pressure switch - have an example?

Sun Aug 02, 2020 2:30 pm

nmerrill wrote: Pressure switch is a simple solution, but I wasn't aware of any low psi examples-

You mentioned a 3 psi pressure switch - have an example?

I thought one of the WBX engine oil pressure switches was 3 psi?
I am not a WBXer, so better wait for a reply from a Mark.... :wink:
The thread would be metric 1/8-28 BSP

I suspect anything under 10 psi would suffice.

Sun Aug 02, 2020 3:49 pm

Something like this. https://www.jbugs.com/product/021919081B.html

Sun Aug 02, 2020 7:03 pm

Sodo wrote: nmerrill wrote: Pressure switch is a simple solution, but I wasn't aware of any low psi examples-

You mentioned a 3 psi pressure switch - have an example?

I thought one of the WBX engine oil pressure switches was 3 psi?
I am not a WBXer, so better wait for a reply from a Mark.... :wink:
The thread would be metric 1/8-28 BSP

I suspect anything under 10 psi would suffice.

Big buzzer sound :lol: :lol:

1/8 of an inch and 28 tooth per inch ain`t metric mon ami, and BSP is British Standard Pipe (thread).

Please apologize to the French Metric system immediately :lol: :lol: :lol:

Back on topic, careful with the VW pressure switch choices, some are NC and some are NO :wink: Their thread is M10x1 ( parallele threads of course) which is veeeery close to some Imperial threads.

Mon Aug 03, 2020 3:57 am

ALIKA T3 wrote: Sodo wrote: nmerrill wrote: Pressure switch is a simple solution, but I wasn't aware of any low psi examples-

You mentioned a 3 psi pressure switch - have an example?

I thought one of the WBX engine oil pressure switches was 3 psi?
I am not a WBXer, so better wait for a reply from a Mark.... :wink:
The thread would be metric 1/8-28 BSP

I suspect anything under 10 psi would suffice.

Big buzzer sound :lol: :lol:

1/8 of an inch and 28 tooth per inch ain`t metric mon ami, and BSP is British Standard Pipe (thread).

Please apologize to the French Metric system immediately :lol: :lol: :lol:

Back on topic, careful with the VW pressure switch choices, some are NC and some are NO :wink: Their thread is M10x1 ( parallele threads of course) which is veeeery close to some Imperial threads.

😀😀😀

Mon Aug 03, 2020 4:00 am

1/8” npt and 10 mm x 1.0 are very similar. The difference is the metric switch requires a crush washer to seal. The 1/8” npt will seal on the threads.

Mon Aug 03, 2020 10:20 am

OK apologies to the French and all......

Re: integrating a pressure switch to the "Temperature Control (electric) - Manual Transaxle gearoil cooler" .

Choosing a Vanagon switch may require a gangly contraption of adapters, piled up like thread bloat.

Probably best to look for a low-pressure switch of "known thread adaptation". Perhaps from an American engine?