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Oil too cold--can't install oil cooler shutter

donaziza

Well Known Member
Hi guys, I'm a non builder. My 8 has an ECI IO 360. Three days ago, I was up at altitude, and my oil temp was only 137*. (OAT was 34*F) A number of years back, I had one of those oil cooler shutters installed in back of my oil cooler. Didn't do any good. Last winter, I asked my mechanic if he could install in front of the cooler. Turns out, it wouldn't fit. So last night, I sent an email to Allen at Anti splat, and asked him if he could make me a custom one that "does" fit. He said Nope, wrong machinery in his shop. So for the last coupla years, I've been putting metallic tape on the front of as much of the cooler as I can squeeze my fingers down, behind the #4 cylinder. So the obvious question is---any of you guys got any ideas??

Luckily, I live in Atlanta, where it generally doesn't get too cold. If I lived in Milwaukee, where I grew up, zero to 17* F is not uncommon.:eek:
 
Hi guys, I'm a non builder. My 8 has an ECI IO 360. Three days ago, I was up at altitude, and my oil temp was only 137*. (OAT was 34*F) A number of years back, I had one of those oil cooler shutters installed in back of my oil cooler. Didn't do any good. Last winter, I asked my mechanic if he could install in front of the cooler. Turns out, it wouldn't fit. So last night, I sent an email to Allen at Anti splat, and asked him if he could make me a custom one that "does" fit. He said Nope, wrong machinery in his shop. So for the last coupla years, I've been putting metallic tape on the front of as much of the cooler as I can squeeze my fingers down, behind the #4 cylinder. So the obvious question is---any of you guys got any ideas??

Luckily, I live in Atlanta, where it generally doesn't get too cold. If I lived in Milwaukee, where I grew up, zero to 17* F is not uncommon.:eek:

Which cooler are you using?
 
Blocking off the air in front of the cooler will definitely make a difference, but may may not get you to where you are thinking you need to go. I had a plate bolted to the back side of my cooler that completely blocked flow through air, and it only made a difference of about 10* f. Like you, I had trouble getting my oil temperature to 140. I put Alan’s Venetian blind blocker on the front of my cooler, (controllable), removed the back plate, and it made a big difference. I talked to Alan a couple weeks ago because I was still not able to get more than 150-160* on a cold day in Ohio, and I learned a few things about oil temperature from him. The temperature you are reading on your gage or EFIS is the temperature after the oil cooler, if the vernatherm is open, prior to going to your bearings. This oil gets MUCH hotter after the bearings and splashing off from the crankshaft onto the 500*+ piston skirts. Any moisture in the oil at this point flashes off almost instantly. Moisture in your engine isn’t a problem if you’re north of 140-150 for a little while as it evaporates through the breather.
If you can block off air in front of the cooler to get to 150*+, I don’t think you have a problem. Most people with oil temperature problems are on the other end and that is more difficult to deal with.
 
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I would double check that your oil sender is reading the correct temp. I can’t imagine how you can almost block the entire cooler and not see higher temps.
 
Don,
My mechanic (Randy "Monk" Richmond at Richmond Aircraft, 52F) built a flapper door that he attached to the baffle wall in front of KELLI GIRL's oil cooler. It's hinged across the bottom with extruded piano hinge (curled hinge will fail from vibration). I control the door with a panel-mounted button-lock push/pull control cable in the middle.

I am able to PRECISELY control the oil temps with this thing, summer or winter. If you want photos, let me know.

Also, I agree that you should test your temp sensor.
 
Some of us just have really cool running engines. My engine, like Don’s runs cool. I tested my oil temp probe in a cup of water with two other thermometers and all three were within 3-4* of each other, and were that way all the way from starting to heat the water to when it got to 200*, so I’m confident my probe is OK. I’m running the standard Vans 7 row Stewart Warner style Aero Classic oil cooler.
If the OAT is below about 35*, I’ll have the shutter completely closed, blocking all air at the front of the cooler, and the temp might get up to 160*. During some acro a few days ago, I saw 170*. I opened the shutter a couple clicks (Bowden cable) and within 2-3 minutes, the temp was down to 160, so I know the mechanism is working.
In the summer time, with no shutter installed I will typically see 175-185*. The most I’ve seen on very hot days after a long climb and some acro is 192*. I’m pretty happy with it.

B4A49676-C984-4E48-83CC-090CCE9D33F4.jpg
 
Vernatherm

Consider checking/replacing your vernatherm. It functions as the thermostat for your oil system and will keep your oil temperature where it should be if functioning correctly. A shutter should not be necessary. Bear in mind if your oil temperature is too low now (I think you said 135 degrees) the vernatherm might be stuck at some intermediate position instead of closing to keep the oil within the engine until warm enough to route to the oil cooler. If that is the case, whatever position it is in may not be fully open and you may have hot oil in the summer.
 
Luckily, I live in Atlanta, where it generally doesn't get too cold. If I lived in Milwaukee, where I grew up, zero to 17* F is not uncommon.:eek:

It is surprising how different the setups can be. On my 6A, I don't think I have every gone above 190 more than twice and I routinely get 160 in the Chicago winters with an occassional 150 on brutely cold days. I can accept 160, so never bothered with a shutter.

Larry
 
2 oil temp sensors?

Does it make sense to consider another oil temp sensor to see the oil temperature as it leaves the hot part of the engine? I have low temps even on "hot" days (30c) but don't want to make changes if there's not really a problem. I think I may have overshot a little when I installed my oil cooler with a slight setback, providing it too much airflow. Perhaps Allan Nimmo is going to get more of my money... https://antisplataero.com/products/oil-cooler-air-shutter

img_9650.jpg
 
my take, for what it's worth...

The oil on my O-360 is also erring on the lo side... mounted on the FW, half of the cooler's exit was closed by a fixed plate. Removed said plate and installed the Splat shutter, results:
Mitigated, the shutter works good, but the results are still not what I'm looking for. Shutter fully closed and my engine still struggles to rise the oil to the desired 180°F.

This winter is pretty cold, as example had -19°C (-2.2F) OAT today at 12.5Kft, and despite using hi power settings the oil refused to climb above 135°F...

Next step will be the installation of some cowling intake blocking plates held by a couple of screws, removable when summer finally comes...
 
I have installed blocking plates to sit between the baffles & oil cooler on many RVs up here, secured with a couple screws. Our situation up here is a bit different in that once we block off the oil cooler, generally we don't have to take it off till spring, doesn't have to be adjustable to your temp swings.

Different situation but interesting observation, while figuring out how to block off the radiators on a Turbo Subie installation during winter (-15 celcius) flight testing.
Aluminum tape on radiators non effective, Duct tape on rad better but still poor results, Corrugated cardboard wrapped with aluminum tape very effective in preventing over cooling.
 
Does it make sense to consider another oil temp sensor to see the oil temperature as it leaves the hot part of the engine? I have low temps even on "hot" days (30c) but don't want to make changes if there's not really a problem. I think I may have overshot a little when I installed my oil cooler with a slight setback, providing it too much airflow. Perhaps Allan Nimmo is going to get more of my money... https://antisplataero.com/products/oil-cooler-air-shutter

View attachment 6694

Mickey,
I did the same offset on my first RV8. I put the oil cooler shutter on the forward side, and it worked very well. I removed it in the summer because it blocked a little airflow when fully open, but that was easy to do. If you want to mount a probe in the hot section of the engine, I don’t know how/where you would do that, but Alan Nimo does. Call him.
 
Two questions on topic

I’m not sure how, with a properly functioning vernatherm, oil temps would be that low? Can the block really be that cool? Second question, it it real, or is it possible the oil temp sensor itself is cooled directly by the incoming air? After all, it’s just a variable resister, right?

I’m one of those H2 guys, so my view might be a little warped, my oil temp sensor is on the non-pressurized side of the baffle.
 
A word of caution if you install the shutter device - if you install the shutter, be advised, the flange on your oil cooler, mating with the flange on you baffling mount is likely wider than the edge of the shutter where it is riveted together. When you tighten your bolts on the cooler, it will squeeze the part of the shutter where the moving part needs to slide and it may not be able to move/slide. You’ll need a narrow spacer on the front side and the back side of the shutter to prevent this from happening. See pic below:

59A9CC7E-9532-4A4B-B691-9FE4E3ACA3CE.jpg

This thin metal strip is just over the riveted area of the shutter, front and back sides, so it doesn’t squeeze the sliding area of the shutter. I used that 3M “riveting tape” to hold it in place while I bolted it up. The shutter works great.
 
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One more variable

Back to Ricks point about cooling the oil temp sensor. I have a complete cooler block with alum Plate for winter (midwest) and calibrated oil temp reads 170-180 all winter. But, my chts are relatively low, 280-290 under cruise power. If you are not running 350+ cht’s, you may be getting cooling that the blocked cooler cannot control even if the vernaterm is completely by passing the cooler ?
 
Oil too cold

For what it’s worth. I run my engine with 6 quarts of oil in the winter (in Minnesota) and the oil temperature comes up to the 190 range. I have my oil cooler completely covered, but I couldn’t get the temp above 160 when I was running 7 quarts of oil. At 6 quarts - less oil gets hotter.

Best regards,

Bill Wuorinen
RV-7A N237W
Osprey 2 N137W
 
An additional caution if you install the shutter. When I moved mine from aft of the cooler
to the front I had to shorten the operating lever to make it fit. But also needed is
rounding off the upper outboard corner of the shutter so that it doesn't rub when the engine vibrates. On my 7A it wore a small hole in the cowl.

Gary R. Kohler
RV-7A
 
Vernatherm question to mechanics.

There doesn’t seem to be too much to the Vernatherm but a ball valve and a spring according to the photos. Can they be adjusted by tightening or loosening the castellated nuts a click or two either way and replacing the stop pin to control temperature. Or is that actually a pressure control? :confused:
My engine manual shows a minimum of 160 required but I thought failure to keep your oil in the 180 to 190 range would invite a lot of moisture to collect in the crankcase and cause corrosion. :eek: On these colder days I could only get my temp up to around 160 on a new O-360 so I installed a shutter but haven’t been able to test it yet. :(
 
A word of caution if you install the shutter device - if you install the shutter, be advised, the flange on your oil cooler, mating with the flange on you baffling mount is likely wider than the edge of the shutter where it is riveted together. When you tighten your bolts on the cooler, it will squeeze the part of the shutter where the moving part needs to slide and it may not be able to move/slide. You’ll need a narrow spacer on the front side and the back side of the shutter to prevent this from happening. See pic below:

View attachment 6712

This thin metal strip is just over the riveted area of the shutter, front and back sides, so it doesn’t squeeze the sliding area of the shutter. I used that 3M “riveting tape” to hold it in place while I bolted it up. The shutter works great.

An additional caution if you install the shutter. When I moved mine from aft of the cooler
to the front I had to shorten the operating lever to make it fit. But also needed is
rounding off the upper outboard corner of the shutter so that it doesn't rub when the engine vibrates. On my 7A it wore a small hole in the cowl.

Gary R. Kohler
RV-7A

I had both of these issues with the standard Vans cooler and the M1B. I do fly in 0F and less occasionally and have never had a low temp issue. I have made other changes that shrunk my hot side envelope but never an issue in cold before or after.

That is a tricky little shutter to install and not compress the mechanism. I shortened my lever and added a bell-crank to operate for more elegant cable routing. BTW - Mine got so easy to move, a locking cable was required as it would not stay in closed, or open, position.
 
vernatherm

There doesn’t seem to be too much to the Vernatherm but a ball valve and a spring according to the photos. Can they be adjusted by tightening or loosening the castellated nuts a click or two either way and replacing the stop pin to control temperature. Or is that actually a pressure control? :confused:
My engine manual shows a minimum of 160 required but I thought failure to keep your oil in the 180 to 190 range would invite a lot of moisture to collect in the crankcase and cause corrosion. :eek: On these colder days I could only get my temp up to around 160 on a new O-360 so I installed a shutter but haven’t been able to test it yet. :(
I had the same question - it seems according to various other threads that even if fully open there is a bit of flow through the oil cooler to ensure that it does not congeal the oil in there. That seems to be one element that's keeping the oil cooler than desired.

Lots of good info here:

https://vansairforce.net/community/showthread.php?t=45548
 
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There doesn’t seem to be too much to the Vernatherm but a ball valve and a spring according to the photos. Can they be adjusted by tightening or loosening the castellated nuts a click or two either way and replacing the stop pin to control temperature. Or is that actually a pressure control? :confused:
My engine manual shows a minimum of 160 required but I thought failure to keep your oil in the 180 to 190 range would invite a lot of moisture to collect in the crankcase and cause corrosion. :eek: On these colder days I could only get my temp up to around 160 on a new O-360 so I installed a shutter but haven’t been able to test it yet. :(

Saw that same photo on another thread and was going to correct it but didn't...

THAT thread showed the oil pressure relief valve. It's on the right side of the engine case and is nothing but a ball, spring and screw to adjust spring preload - that device is NOT the vernatherm.

The vernatherm is usually in the oil filter adapter and driven closed by a temperature sensitive wax pellet. When cold, the wax pellet withdraws the cone shaped valve off the seat and allows oil to bypass the cooler. When hot, the valve seats and blocks the bypass flow. The "usual" vernatherm issue is that the cone valve does not seat effectively when hot, allowing some oil to bypass the cooler and run too hot.
 
Saw that same photo on another thread and was going to correct it but didn't...

THAT thread showed the oil pressure relief valve. It's on the right side of the engine case and is nothing but a ball, spring and screw to adjust spring preload - that device is NOT the vernatherm.

The vernatherm is usually in the oil filter adapter and driven closed by a temperature sensitive wax pellet. When cold, the wax pellet withdraws the cone shaped valve off the seat and allows oil to bypass the cooler. When hot, the valve seats and blocks the bypass flow. The "usual" vernatherm issue is that the cone valve does not seat effectively when hot, allowing some oil to bypass the cooler and run too hot.

Very interesting. A lot of people have pointed to that thing and tell me that it’s the vernatherm . I worked in the pipeline industry and always wondered how it worked with temps since it sure looked like a pressure relief valve to me. A lot of bad info out there. Thanks
 
TOCBV

The Thermostatic Oil Cooler Bypass Valve was designed to provide better control of the engine oil temperature while also maintaining the safety of the oil system by bypassing oil around an oil cooler which is plugged for any reason. The thermostatic oil cooler bypass valve may be used on engines which use the pressure screen system and on engines which have a full-flow oil filter. For most engine models, an oil filter also requires an oil filter adapter. While the oil is cold, this system allows oil to flow through the oil filter without passing through the oil cooler. As oil temperature rises to approximately 180˚ F, the valve closes and forces the oil to pass through the oil cooler. The oil then returns to the accessory housing where it is routed through the oil filter adapter, the filter and then again through the filter adapter, accessory housing and finally into the crankcase.
 
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