What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

temporary oil cooler restrictor plate?

Paul K

Paul K

Well Known Member
Ok, I should have done somthing about this during my last annual or at least when it was warmer outside but then again who thinks of this stuff when it's warmer outside? I want to install a temporary oil cooler restrictor plate. has anyone done this and are there any photos? I am heading to the airport to pull the cowl to see what can be done and then ordering or making a shutter system for perminate use later. But for now, I really need to get the oil temps up.

My ride back from lunch a few minutes ago. This is what we are dealing!

IMG_2399.gif
 
The oil cooler air flow can be restricted with a simple piece of cardboard and or tape for trial flights in the pattern, then when you have the size you want, make one from aluminum sheet. It could be bolted in, taped in, or perhaps you can figure out a way to make it so it holds itself in place by being springy. Try not to damage the fragile cooler fins while you are working in there. Also, make sure it won't get loose and flutter around.
Consider a roll of aluminum tape, handy for sealing baffles etc. that might be good for temporary or trial air control.
I probably should mention to use preheat during cold weather, but you already know that.
 
Last edited:
I use simple aluminum speed tape. Simple. Easy on and off. Also useful for many other things. I block about 70% of mine.
 
Gorilla tape works good too, and doesn't crack into tiny pieces that get stuck in the oil cooler fins like aluminum foil tape does after it's been exposed to enough vibration over time.
 
Or you might just want to buy the oil cooler shutter which will be good for this season, next and the next after that and each time you won't have to take the top cowl off to change it.

I use mine even in summer time if I need to raise the oil temp a bit at higher altitude.
 
Last edited by a moderator:
Look for aluminum tape at a hardware store or DIY box store. It might be located in the heating and ventilation section since it is used for ducting joints. It is 2" wide by very thin aluminum with adhesive backing on a paper liner. Peel the paper liner way and stick to the face of the oil cooler.
 
just a heads up, I do not work with that stuff (and we use a lot of it during RENO) without wearing gloves, its thin and can be very sharp!

bob burns
RV-4
N82RB
 
Aluminum tape

My engine is cold blooded and I start "winterizing" oil cooler early.

October needs just a little strip. November asks for 50% blockage to keep oil in the green.









In December I block all inner wall of oil cooler. I have a plenum and a larger cooler and can barely keep oil temps around 170F.







In January/Feb I completely block both sides of the oil cooler. One side wasn't enough to keep oil warm. It really helps.







Then sometime in March the procedure gets reversed. Tape peels off little by little every time during oil changes. :)
 
which side to block?

If you know the actual flow direction of the oil, and when, is there a best way to raise the oil temp?
My plane came with a plate that bolted to the back of the oil cooler. with a few washers, you could allow perhaps 15% flow, or flush with the rear, almost nothing.
I think a possible benefit might be that the front gets some warm air off the top of the cylinder fins, so when the vernatherm lets some oil thru, in theory, the cooler isn't a brick of cold thick oil.
This question arises every year for me; if the engine is cold, why would the vernatherm let ANY oil thru to to cooler, until it really NEEDED to be cooled?
why do we block it off? ( not unlike the rad in your car, there's no flow until cooling is needed.)
Now I totally see the need to limit airflow into the COWL........but very few guys do that, first anyway. ( me included) cause it's a bit harder to do.
Someone please educate me?
 
Vlad, I'll try it!

Just for base numbers, I flew for 45 minutes Friday with an outside air temp of about 20 and my oil temp actually hit 138, once! Mostly closer to 125. Heading to HD Aviation to see what kind of tape I can find. Will work on a better fix later but the tape will give me a good idea of how much to block off.

Other base data:
WOT
3500 to 5500 feet altitude
Prop pulled to 2350 rpm
50 degrees LOP
Hottest EGT 1320, about 30 degree spread
Hottest CHT 312, coldest CHT 289
7.8 gph
168k TAS


Thanks
 
flyboy1963 said:
If you know the actual flow direction of the oil, and when, is there a best way to raise the oil temp?
My plane came with a plate that bolted to the back of the oil cooler. with a few washers, you could allow perhaps 15% flow, or flush with the rear, almost nothing.
I think a possible benefit might be that the front gets some warm air off the top of the cylinder fins, so when the vernatherm lets some oil thru, in theory, the cooler isn't a brick of cold thick oil.
This question arises every year for me; if the engine is cold, why would the vernatherm let ANY oil thru to to cooler, until it really NEEDED to be cooled?
why do we block it off? ( not unlike the rad in your car, there's no flow until cooling is needed.)
Now I totally see the need to limit airflow into the COWL........but very few guys do that, first anyway. ( me included) cause it's a bit harder to do.
Someone please educate me?
Click to expand...

First... The vernatherm is NOT like an automotive thermostat except that both move in relation to temperature. The automotive thermostat closes and blocks flow of water in a deadheading sort of way. Would you want your oil flow 100% blocked? Probably not.

The vernatherm is an oil cooler bypass. It is in parallel to the cooler. The vernatherm valve is open when cold. This means the oil has two paths it can take, through the cooler or through the vernatherm and on to the rest of the oil system. When temperature rises, the vernatherm closes and shuts off the bypass path. All oil is forced through the cooler at that point. So the valve changes the oil flow through to cooler from some to all, not from none to all.

If the flow of oil through the cooler (with vernatherm open for max bypass) is still too much and your oil temperature is too low, then the cooling fins need to be blocked.
 
Even when a vernatherm is "open" some amount of oil still flows thru the cooler. I've found that even when both the front and back sides of the oil cooler are blocked off in my O-320 RV-6 in very cold weather, that I still have difficulty getting the oil temps up to 180 but blocking off the front side is more effective than blocking off the rear.

I've built a flapper door to cover the rear and it's hooked up to a push pull cable I can control from the cockpit, but when the weather gets really cold, I also have a piece of flat aluminum sheet that I put over the front of the cooler and tape it into place with Gorilla tape.
 
rzbill,

Thanks for that explanation on the vernatherm. That has also puzzled me , I thought it worked like a coolant thermostat. I must have a very efficient cooling system since my IO 360 rarely rises above 165 in the summer and gets progressively cooler in the winter months. I am going to verify my temperature is accurate and then start restricting the airflow through my cooler. I would really like to see it get in the 180-195 range to burn off the condensation in the motor. I looked all over for a diagram or explanation on the oil system and vernatherm operation; do you have any official references on this system?
 
Dave,
You are welcome.
I understand the 180 hp Lycomings commonly have cool oil temperatures when installed well per Vans plans. Mine does too. I need 1/3 to 1/2 coverage in the summer to get 170 to 180F temp indication. Even more in the winter.

DanH has posted some good oil systems diagrams here. Search his Id and the word vernatherm in the advanced search area and you will find them.
 
Last edited:
I installed the oil cooler shutter from Van's, with an in-cockpit push-pull cable and it works *great*. I've never had high oil temps even in summer, and I can precisely control it when needed to bring it up above 180 when it's cold (in fact, I can change the temp by just a degree or two with fine movements of the cable if I want).

No speed tape, no need to decowl and fuss around with adding or removing it, etc. Highly recommend it.
 
Van's oil shutter

Paul, I have a Van's oil shutter that i took off my plane. It has the pull cable and the longer AN bolts that you need. Email me if your interested.

Matt
[email protected]
 
Aluminum tape

I found this:

Nashua Aluminum Waterproofing Repair Foil Tape, 11 mil Thick, 10 m Length, 48 mm Width

at Amazon. It is much thicker than the tape used to repair ducts.
 
You must log in or register to reply here.
Back
Top