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Oil baffle and oil temps

Saville

Well Known Member
So every Fall I attach an aluminum plate to the backside of my oil cooler to try and keep the oil temps up. It seemed to work ok though the temps were never very high.

I would take it off in the Summer. But once off, the temps rarely got above 180 degrees. Usually more like 160.

This Spring and Summer I kept the baffle on. It's mid August and it's still on. Now the temps are 180-190. 200 if I have to sit at the hold short line for a long time. Temps are int eh green during climbs.

I'm wondering if my Verna-therm is working? I would think that baffle would need to come off in the Summer but so far I can see no need.

Strikes me that something isn't right here.

What do you all think?
 
P.S. After one flight I ran a temperature check by measuring the oil temp with a thermometer and comparing that to the instrument readout. They coincided.

I thought that maybe the readout was incorrect but that possibility was eliminated.
 
If the verna-therm was working, why did the oil temps never exceed 160 when the baffle was not installed?

Because there is always some flow through the oil cooler, regardless of vernatherm position.

The vernatherm extends when warmed. It is fully extended at about 185F. When it extends, it blocks a bypass hole. With the bypass blocked, all oil is routed through the cooler.

At 160F, the vernatherm is retracted, and the bypass is open. Oil flows through both the cooler and the bypass.
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My oil temps run low during the winter as well. I just installed a set of the cooler shutters, we'll see how they do (haven't flown them yet). My install is not ideal with the shutter on the cooler outlet, but install on the inlet would have required much more baffle rework. Since I am in the south, It isn't as great an issue as many northerners have. Problem here in Texas is that the temps can swing wildly, so just a simple blockoff plate would be a pain.
 
Well to be clear, my problem is that the oil is too cool in the Summer as well as Winter.

The only way I can get the oil temps at or above 180 degrees in the Summer is to keep the baffle block on.

This doesn't seem right to me.
 
Well to be clear, my problem is that the oil is too cool in the Summer as well as Winter.

The only way I can get the oil temps at or above 180 degrees in the Summer is to keep the baffle block on.

This doesn't seem right to me.

"Summer" and "winter" are meaningless in terms of analysis. The conditions of interest are engine type, OAT and power setting. Parallel valve engines without piston squirters require less oil cooling. Heat transfer rate is influenced by DeltaT, oil to air. And LOP operation typically reduces both CHT and oil temperature.

180F is perfect, per Lycoming. If you're there, you're fine. I assume your concern is oil temp in the 150's and 160's when OAT and power are both low. If someone it telling you oil must reach 212F to boil off water, hand him a physics text.

The "always flow in the cooler" design was to accommodate very cold climate operation, and yes, that is rather counter-intuitive given it tends to over cool the oil. The problem was single weight oil in the cooler becoming so viscous in an arctic blast that it would not flow, forming a plug of sorts in the cooler during the initial phase of flight. As oil temp rose, the vernatherm would try to close, but oil couldn't flow through the plugged cooler, and with no flow, it would not warm enough to unplug. That's why a vernatherm has a spring loaded tip (see below). The warming vernatherm will extend to block the bypass, but if the cooler is plugged, the tip will float off the seat at about 15 psi deltaP, allowing continued oil flow to the engine.

You can gain absolute control of cooler flow rate by removing the vernatherm, then installing a "viscosity valve" spring and plunger assembly in the accessory case, and a 1/4 turn ball valve in one of the cooler lines. The valve can be cockpit controlled. The SI attached below explains how to remove the viscosity valve and replace it with a vernatherm. Just reverse the process.
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Well to be clear, my problem is that the oil is too cool in the Summer as well as Winter.

The only way I can get the oil temps at or above 180 degrees in the Summer is to keep the baffle block on.

This doesn't seem right to me.
I have the same "problem", but I'm not really convinced it is a problem. If the only reason for the desired higher oil temperature is getting the combustion water out of the oil, and we all know that much water will go out the breather, and water will evaporate at lower temperatures with lower pressure, and there are plenty of spots in the engine with very high temperatures (like under the piston), do we really need to get the oil up to 180? Is 160 warm enough? If the oil is flowing, lubricating, capturing particles, protecting against corrosion, and cooling the engine, why do we care if the temp is 150 or 200? Are there special additives in the oil that are only activated at a specific temperature?
 
"Summer" and "winter" are meaningless in terms of analysis. The conditions of interest are engine type, OAT and power setting. Parallel valve engines without piston squirters require less oil cooling. Heat transfer rate is influenced by DeltaT, oil to air. And LOP operation typically reduces both CHT and oil temperature.

180F is perfect, per Lycoming. If you're there, you're fine.

I am NOT there. That's the problem.

I assume your concern is oil temp in the 150's and 160's when OAT and power are both low.

All incorrect assumptions.

All the rest, below, ignored as not relevant to the question. No one said anything about needing 212. No one is talking about a plugged cooler in the summer time.


If someone it telling you oil must reach 212F to boil off water, hand him a physics text.

The "always flow in the cooler" design was to accommodate very cold climate operation, and yes, that is rather counter-intuitive given it tends to over cool the oil. The problem was single weight oil in the cooler becoming so viscous in an arctic blast that it would not flow, forming a plug of sorts in the cooler during the initial phase of flight. As oil temp rose, the vernatherm would try to close, but oil couldn't flow through the plugged cooler, and with no flow, it would not warm enough to unplug. That's why a vernatherm has a spring loaded tip (see below). The warming vernatherm will extend to block the bypass, but if the cooler is plugged, the tip will float off the seat at about 15 psi deltaP, allowing continued oil flow to the engine.

You can gain absolute control of cooler flow rate by removing the vernatherm, then installing a "viscosity valve" spring and plunger assembly in the accessory case, and a 1/4 turn ball valve in one of the cooler lines. The valve can be cockpit controlled. The SI attached below explains how to remove the viscosity valve and replace it with a vernatherm. Just reverse the process.
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Ok my wondering if the Vernatherm was malfunctioning (or incorrectly set) was based on the possibility that it was letting oil flow to the cooler BEFORE it got to 185. Nothing you've said proves that this isn't happening. But let's not go down that rat hole right now.

So I'll restate the question:

Flying the Northeast, OAT~68, O-360, level at 23 squared, or climbing at 24 squared, no baffle plate on the back side of the oil cooler blocking the air flow, I can't get my oil temps up to 180.

In the Winter, with the baffle plate on, I can't get the oil temps up to 180 in any flight regime.

Oil cooler is at the left hand side of the engine baffle.

This strikes me as unusual. Is it?

Most of the times I see people talking about oil temp problems, they are talking about oil getting too warm - especially in the climb. I've read lots of those.

Is this a common problem (oil temps too low) requiring some alteration the air flow-through in the oil cooler?

I would have thought that given the oil temp sweet spot of 180 , that designs would be such that they would get you in that vicinity. Maybe I'm wrong.

So, flying in the Northeast:

With no baffle on the oil cooler I rarely get my summer flying temps above ~160

With a full plate on the back of the oil cooler I can't get my oil temps up above 160. Usually it's less.

I would have thought that is unusual.
 
I have the same "problem", but I'm not really convinced it is a problem. If the only reason for the desired higher oil temperature is getting the combustion water out of the oil, and we all know that much water will go out the breather, and water will evaporate at lower temperatures with lower pressure, and there are plenty of spots in the engine with very high temperatures (like under the piston), do we really need to get the oil up to 180? Is 160 warm enough? If the oil is flowing, lubricating, capturing particles, protecting against corrosion, and cooling the engine, why do we care if the temp is 150 or 200? Are there special additives in the oil that are only activated at a specific temperature?

My only concern is that it's not getting the water out of the oil. I'm only concerned about that because I read about that being a problem, a lot.

I'm not qualified to say whether or not it's a problem.

If the Lycoming manual says that the sweet spot for oil temps is 180, I'd like to be there if possible.
 
Lycoming seems to be comfortable with oil temps lower than 180˚F - the Thermostatic Oil Cooler Bypass Valve actives at 180:

https://www.lycoming.com/content/understanding-oil-flow

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.


https://www.lycoming.com/content/op... desired oil temperature range,to 45˚ F range.

Engine operating temperature is another item that is not usually given enough consideration in cold weather. We usually are very cautious about high oil temperature which we know is detrimental to good engine health, while a low oil temperature is easier to accept. The desired oil temperature range for Lycoming engines is from 165˚ to 220˚ F. If the aircraft has a winterization kit, it should be installed when operating in outside air temperatures (OAT) that are below the 40˚ to 45˚ F range. If no winterization kit is supplied and the engine is not equipped with a thermostatic bypass valve, it may be necessary to improvise a means of blocking off a portion of the airflow to the oil cooler. Keeping the oil temperature above the minimum recommended temperature is a factor in engine longevity. Low operating temperatures do not vaporize the moisture that collects in the oil as the engine breathes damp air for normal combustion. When minimum recommended oil temperatures are not maintained, oil should be changed more frequently than the normally recommended 50-hour change cycle. This is necessary in order to eliminate the moisture that collects and contaminates the oil.

I use an engine dryer which I believe helps remove moisture from the engine. My Blackstone analysis always shows no water, so I guess it's working.
 
Ok my wondering if the Vernatherm was malfunctioning (or incorrectly set) was based on the possibility that it was letting oil flow to the cooler BEFORE it got to 185. Nothing you've said proves that this isn't happening.

Re-read post #5

Again, there is always oil flow through the cooler.

A cold vernatherm allows some of the oil through an open bypass, while some flows through the cooler. A hot vernatherm closes the bypass, forcing all the oil through the cooler.

I've attached a special drawing below. Study carefully.

A vernatherm has no user-adjustable setting.

What oil cooler do you have?
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Re-read post #5

Again, there is always oil flow through the cooler.

A cold vernatherm allows some of the oil through an open bypass, while some flows through the cooler. A hot vernatherm closes the bypass, forcing all the oil through the cooler.

I've attached a special drawing below. Study carefully.

A vernatherm has no user-adjustable setting.

What oil cooler do you have?
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Read carefully the first paragraph of my #10 reply.
 
Gregg, is there some specific technical point you feel is incorrect, or requires proof?
 
Gregg, is there some specific technical point you feel is incorrect, or requires proof?

The problem is that you are not addressing the question.
I'm getting admonitions about demanding 212 degrees to boil off the water in the oil and dissertations on coolers plugged with congealed single weight oil in Winter.

No one says you have to - you can talk about anything you want. But I'm trying to get information on what I'm seeing.


I tried to shut off the vernatherm question because it was just obfuscating things. A defective Vernatherm was only one thought I had.

I don't want proofs. I'm looking for information.

Is it unusual for oil temps to not rise about 160 in Northeast Summer flying when there's nothing impeding the airflow through the oil cooler? Or 140-ish in Winter? Is it a common problem for builders?

Am I seeing something everyone sees and makes adjustments for? Or is there something wrong with my setup?
 
I'm on my second RV-8 in the Pacific NW. The first one had a parallel valve IO-360-A1A with 10:1 HC pistons and LASAR EIs. My current RV-8 has a parallel valve IO-360-M1B with a Slick IC Mag and an LSE Plasma III EI. Both airplanes have the oil cooler mounted behind Cylinder #4. Both airplanes have versions of Hartzell CS props.

Both airplanes have to have the front side of the oil cooler blocked off with AL tape to some degree to keep the oil temps between 165° F and 200° F in cruise.

On my current RV-8, in the winter most (~90%) of the front side of the oil cooler needs to be covered. In the summer, about 40% - 50% needs to be covered. My previous RV-8 was similar.

I found that blocking the backside of the cooler with a piece of AL plate bolted to the back via the mounting holes does not help much to increase the oil temp (~10° F), since air still flows around the tubes.

Hope that helps.
 
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Excess cooler capacity

Short answer, with enough cooler capacity and airflow it seems plausible to experience your low oil temperatures. Normal? Not really because most of us would adjust the cooler inlet during our initial testing to achieve higher temps. Shutters and baffles are common solutions, even during summer months.

While I was fighting high #4 CHT, I was able to cover 1/2 of the cooler face and still keep good oil temps even in very hot conditions (and mostly fixed my CHT issue). You probably are operating with the Vernatherm closed much of the time due to cooling surplus. My take is your situation is normal and would indicate it's worthwhile blocking some of the face of the cooler under most if not all ambient conditions. Like you, I am somewhat frustrated because my Pitts with the same engine and cooler always maintained 180 under all conditions with no shutters or baffles. I can't explain why my RV4 oil temps vary so much based on ambient and power.

That said, even when very cold my RV4 oil temps would get to 180 eventually, I never saw 160 all the time. When I first bought the Pitts the PO had removed the Vernatherm and it ran too hot. A stuck vernatherm could also cause consistently cool operation.

I would start taping over the face of the cooler a little at a time until I achieved 180 plus and then reassess. Hopefully you'll see stable temps settle out near 180 at least for a given ambient condition. I've read some RV`s run with the cooler at or near 100% covered during the winter.

Good luck, I'm eager to hear how it works out.


The problem is that you are not addressing the question.
I'm getting admonitions about demanding 212 degrees to boil off the water in the oil and dissertations on coolers plugged with congealed single weight oil in Winter.

No one says you have to - you can talk about anything you want. But I'm trying to get information on what I'm seeing.


I tried to shut off the vernatherm question because it was just obfuscating things. A defective Vernatherm was only one thought I had.

I don't want proofs. I'm looking for information.

Is it unusual for oil temps to not rise about 160 in Northeast Summer flying when there's nothing impeding the airflow through the oil cooler? Or 140-ish in Winter? Is it a common problem for builders?

Am I seeing something everyone sees and makes adjustments for? Or is there something wrong with my setup?
 
Is it unusual for oil temps to not rise about 160 in Northeast Summer flying when there's nothing impeding the airflow through the oil cooler? Or 140-ish in Winter? Is it a common problem for builders?

Apparently it is common, given you read about it a lot:

My only concern is that it's not getting the water out of the oil. I'm only concerned about that because I read about that being a problem, a lot.

Brad and Mike seem to suggest the vernatherm could be defective, i.e. perhaps locked in the extended position, or extending prematurely at a temperature lower than spec. I doubt it, but I'm always in support of checking to be sure.

Unscrew the vernatherm. There will be a visible contact ring on the conical tip. Measure from the underside of the gasket to the wear ring. A cold, fully retracted vernatherm should ballpark around 3.120". If extended and locked so as to block the bypass port, it will measure 3.280". Please report back.

The Rosta temperature vs extension spec below.
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Apparently it is common, given you read about it a lot:

What I read about a lot is that you must get the oil temps up to 180. I don't read a lot about people having trouble doing that. If I had, I would have read their posts to get remedies. Perhaps my search didn't find them.

Brad and Mike seem to suggest the vernatherm could be defective,

Which I also suggested in my original post and which you said, outright, that it was working fine and was not the source of the problem.

i.e. locked in the extended position, or extending prematurely at a temperature lower than spec. I doubt it, but I'm always in support of checking to be sure.

So evidently you now think it's possible (though unlikely in your opinion) that the Vernatherm isn't working.

Unscrew the vernatherm. There will be a visible wear ring on the conical tip. Measure from the underside of the gasket to the wear ring. A cold, fully retracted vernatherm should ballpark around 3.120". If extended and locked so as to block the bypass port, it will measure 3.280". Please report back.

The Rosta temperature vs extension spec below.
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Thanks for the information on how to check for a defective Vernatherm.
 
Oil temperatures and cooler air flow

So every Fall I attach an aluminum plate to the backside of my oil cooler to try and keep the oil temps up. It seemed to work ok though the temps were never very high.

My solution: this is cockpit-controlled. The intake is a 2 inch duct off the back of the baffle and the outlet is a gated 2 inch duct. I leave the gate closed at startup and open it prior to departure. The gate is open in this picture. Temps in the 160-180 range and easily controlled using the gate. Intake is placed so that it does not interfere with airflow over the cylinder.

In the winter I have two simple small round aluminum blocking plates with extensions that fit in the hole, one blocking half the 2 inch intake, the other blocking 3/4 of the intake as the temperatures cool that neatly fit inside the intake fitting. That keeps temperatures above 160 in colder months.

The cooler is attached to the engine mount by a self-made steel bracket: solid as a rock and moves with the mount. I have never had a break in the scat tubing from the baffling to the cooler.
 

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Okay, I'll jump in on this!

It is possible to check the vernatherm by putting it in a pot of water and bring it to a boil...and with a thermometer in the water, you can see the vernatherm extend at about 180. Barrett recommended this to me and I was able to verify its operation while trouble shooting oil temp excursions. Just another thing to check.

FWIW...on my previous -8 (IO-360) I had trouble getting the oil warm enough. I tried the shutter and it was not effective enough. Eventually went to the foil tape on the inside of the cooler and it worked like a charm.
 
To the original question of whether cool oil temps are unusual, not for me.
Mine is a stock lycoming IO360 factory experimental bought through Vans. One slick, one EMag. RV 7. Fixed pitch prop.
I see 160 _ 170 with the cooler blocked with OAT from 20 to 70.
This past July with OAT over 80 I saw 185_190. I took the cooler block off ant saw 160ish again.
It’s never lower than 160.
I run LOP at 75%

So, I can’t say it’s common, but I can say it is not unique.
 
Okay, I'll jump in on this!

It is possible to check the vernatherm by putting it in a pot of water and bring it to a boil...and with a thermometer in the water, you can see the vernatherm extend at about 180. Barrett recommended this to me and I was able to verify its operation while trouble shooting oil temp excursions. Just another thing to check.

FWIW...on my previous -8 (IO-360) I had trouble getting the oil warm enough. I tried the shutter and it was not effective enough. Eventually went to the foil tape on the inside of the cooler and it worked like a charm.

Thanks for the info.

Can you, please, describe the "foil tape on the inside of the cooler" technique a little more?
 
To the original question of whether cool oil temps are unusual, not for me.
Mine is a stock lycoming IO360 factory experimental bought through Vans. One slick, one EMag. RV 7. Fixed pitch prop.
I see 160 _ 170 with the cooler blocked with OAT from 20 to 70.
This past July with OAT over 80 I saw 185_190. I took the cooler block off ant saw 160ish again.
It’s never lower than 160.
I run LOP at 75%

So, I can’t say it’s common, but I can say it is not unique.

Was your cooler block on the air intake of the cooler or on the back of the cooler?

Thanks for the info
 
Which I also suggested in my original post and which you said, outright, that it was working fine and was not the source of the problem.

The reported conditions are not inconsistent with normal vernatherm operation in a carbed parallel valve.

So evidently you now think it's possible (though unlikely in your opinion) that the Vernatherm isn't working.

I think it's easy to check.

Per a conversation with a Rosta engineer some years ago, the most common failure mode is hardening of the wax motor's rubber piston due to age, the result being failure to extend properly. Retraction is powered by an external spring. There are no close tolerance sliding surfaces between the wax motor cartridge and the vernatherm body, so a jam due to debris or deposit seems unlikely. But hey, anything is possible.

Thanks for the information on how to check for a defective Vernatherm.

You're quite welcome. Please report back.
 
Can you, please, describe the "foil tape on the inside of the cooler" technique a little more?

I've applied the AL foil tape on the front side of the oil cooler so I can fold it up or down, depending on the season and how much of the cooler I want to cover, as I mentioned in post #17. You may have to unbolt the cooler so you can get the AL foil tape all the way down to the bottom of the cooler, since the cylinder is in the way otherwise.

i-wKgm5mM-L.jpg
 
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I've applied the AL foil tape on the front side of the oil cooler so I can fold it up or down, depending on the season and how much of the cooler I want to cover, as I mentioned in post #17. You may have to unbolt the cooler so you can get the AL foil tape all the way down to the bottom of the cooler, since the cylinder is in the way otherwise.

i-wKgm5mM-L.jpg

Ah I was confused when in #17 you said "...backside the cooler..." I think of the backside as the side closest to the firewall. But that's just me.

But your picture clears it up now. Thanks for the info.
 
Ah I was confused when in #17 you said "...backside the cooler..." I think of the backside as the side closest to the firewall. But that's just me.

But your picture clears it up now. Thanks for the info.

I see. In post #17 I was saying that attaching an AL plate to the rear side (backside) of the cooler, as you did, only raised the oil temps about 10°F. Placing the AL foil tape to the front of the cooler is much more effective since it blocks flow though the cooler.

Glad the pic helped.
 
I see. In post #17 I was saying that attaching an AL plate to the rear side (backside) of the cooler, as you did, only raised the oil temps about 10°F. Placing the AL foil tape to the front of the cooler is much more effective since it blocks flow though the cooler.

Glad the pic helped.

So far that's the impression I'm getting...that if you have to block off the cooler it's more effective to block it off on the air intake side.

I think I might look into an Anti-Splat baffle and see what it takes to run a cable from that to a knob in the cockpit.
 
I think I might look into an Anti-Splat baffle and see what it takes to run a cable from that to a knob in the cockpit.
I ordered the Anti-splat baffle in advance of doing our first oil change. Although it seems to be really well designed and made - I discovered that with all the added rivets and hard to access screws (up against firewall and blocked by brackets) mounting the duct shroud to the oil cooler - it just wasn't worth the effort. The previous owner used the foil tape over most of the inlet method and we may have to go that route too.
 
2 Follow-up Questions

New RV6A owner - so pardon my beginner questions...
As fall temps arrive here in Wisconsin we also are having difficulty getting the oil temp up above 160 on 24/24 cruise during late summer Wisconsin flights so we're concerned what it will be like when the cold really hits.
1) After reading this thread I'd like to remove and test our (0-360 A1A) engine's Vernatherm - but even after looking at the provided diagrams (but not while in front of the engine) I'm having a hard time figuring out where it is. Can any one point me to the right area?
2) Due to all the added rivets and hard to access screws (up against firewall and blocked by brackets) holding the duct shroud to the oil cooler - trying to install Anti-splat's oil cooler baffle would be pretty difficult. So alternately, does anyone knows a source for an inline cable controlled baffle (e.g. swing gate) for a 3" hose? I could mount it between the hose's inlet plate and the hose or possibly even inline in the 3" hose.
 
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1) After reading this thread I'd like to remove and test our (0-360 A1A) engine's Vernatherm - but even after looking at the provided diagrams (but not while in front of the engine) I'm having a hard time figuring out where it is. Can any one point me to the right area?

Exact location depends on which oil filter adapter you have installed. If the standard Lycoming adapter (filter is horizontal, pointing aft), it's #8 in the attached photo. It screws into the bottom of the adapter.
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Exact location depends on which oil filter adapter you have installed. If the standard Lycoming adapter (filter is horizontal, pointing aft), it's #8 in the attached photo. It screws into the bottom of the adapter.
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Thanks, the picture is a great help! Ours is the horizontal mounted filter.
 
I have a similar issue with my O-360 powered RV6, which has a firewall mounted 7 row cooler, fed with a 3” scat tube. I saw 180* oil temps during my first flights when the surface temps were in the 85-90* range. Now that the OAT has cooled and my engine is broken in (40 hours), I’m seeing oil temps in the 145-160 range with OAT’s in the 45-50* range. I made a baffle to go in front of the oil cooler scat hose attachment as shown:

8621FDC4-B38B-4448-AC95-79C1D5965C51.jpg

This helped a little on the oil temp (5*), but also lowered the #4 CHT by about 10*, which still runs a little hot in full power climbs (385-400). I’ll be covering the bottom half of my 3” opening with Al tape like RV8JD has done to see if that helps - still keeping that added baffle.
 
I have a similar issue with my O-360 powered RV6, which has a firewall mounted 7 row cooler, fed with a 3” scat tube. I saw 180* oil temps during my first flights when the surface temps were in the 85-90* range. Now that the OAT has cooled and my engine is broken in (40 hours), I’m seeing oil temps in the 145-160 range with OAT’s in the 45-50* range. I made a baffle to go in front of the oil cooler scat hose attachment as shown:

This helped a little on the oil temp (5*), but also lowered the #4 CHT by about 10*, which still runs a little hot in full power climbs (385-400). I’ll be covering the bottom half of my 3” opening with Al tape like RV8JD has done to see if that helps - still keeping that added baffle.

Thanks for the picture! I wish I were that handy with fabrication. Is there a control cable (not visible in pic) that allows you to open/close the baffle in flight?
Also I should have mentioned that the oil temps I mentioned are WITH 2/3 of the 3" opening already taped over with alum tape by the previous owner. I'm hesitant to cover it further.
 
I ordered the Anti-splat baffle in advance of doing our first oil change. Although it seems to be really well designed and made - I discovered that with all the added rivets and hard to access screws (up against firewall and blocked by brackets) mounting the duct shroud to the oil cooler - it just wasn't worth the effort. The previous owner used the foil tape over most of the inlet method and we may have to go that route too.

My oil cooler is mounted to the engine baffle so I don't know what the issues would be in installing an Anti-splat shutter between the oil cooler and the baffle.

All this Summer, I kept the airflow blocking plate - which is mounted directly to the after end of the oil cooler - on. I got good oils temps. The highest the temperature got was when I was in a long line of planes holding short, waiting for multiple planes to land between each takeoff. The oil temp got up to 194.

But that means that this Winter, I'll have to do something else to keep the oil warm until I decide whether or not to go with the anti-splat. Maybe tape across the baffle in front of the oil cooler.
 
So far that's the impression I'm getting...that if you have to block off the cooler it's more effective to block it off on the air intake side.

I think I might look into an Anti-Splat baffle and see what it takes to run a cable from that to a knob in the cockpit.
That has been exactly the same experience as I had. I made a shutter for my RV7A which is available for anyone who is interested that would block the air on the aft side of the cooler but it raised the temp only about 10F.

I switched to a shutter type the blocks the air from the front and it was supper effective.
 
That has been exactly the same experience as I had. I made a shutter for my RV7A which is available for anyone who is interested that would block the air on the aft side of the cooler but it raised the temp only about 10F.

I switched to a shutter type the blocks the air from the front and it was supper effective.

Would love to see a picture/drawing of you shutter. Is it a slide style of flap door style?
 
3" to 2" Scat Tube reducer?

I found a shut off valve tube connector that I believe I can install in the scat duct feeding my oil cooler - but would need to reduce to 2" scat duct from the current 3" duct. Unfortunately I haven't been able to find a duct reducer (3" to 2"). Does anyone have a source? Alternately, if I could find a 3" shut off valve tube connector that would be even better.
 
Exact location depends on which oil filter adapter you have installed. If the standard Lycoming adapter (filter is horizontal, pointing aft), it's #8 in the attached photo. It screws into the bottom of the adapter.
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Dan, I'll be back at the hanger tonight and want to be certain I'll recognize the Vernatherm. Is it highlighted in the red circle I've added to attached picture? Thanks, Dave
 

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Here is a picture of the shutter. This fits a RV7 with the cooler mounted behind #4 cylinder baffle and I imagine any other model that has the same oil cooler setup.
 

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Thanks for the picture! I wish I were that handy with fabrication. Is there a control cable (not visible in pic) that allows you to open/close the baffle in flight?
Also I should have mentioned that the oil temps I mentioned are WITH 2/3 of the 3" opening already taped over with alum tape by the previous owner. I'm hesitant to cover it further.

The baffle I made is fixed, attached with two screws from the back. I’ll tape up my oil cooler opening by 1/2 - 2/3, and then reinstall the baffle piece.

Thanks for your pics.
 
it works like a vertical blind, two slats, and opened and closed by a pull/push cable. I will look for it to take a picture.

Thanks for the picture. You made that?? If so that's awesome - but if you bought let please let me know the source.
 
Dan, I'll be back at the hanger tonight and want to be certain I'll recognize the Vernatherm. Is it highlighted in the red circle I've added to attached picture? Thanks, Dave

Well once back at the plane I immediately realized there was no way I'd be able to remove the Vernatherm to test it - access is too limited at least with the tools and limited experience I have. So just finished our first oil change and added some additional foil tape to further restrict the oil cooler air inlet in anticipation of cooler winter temps on the way.
 
If the cooler is too effective, consider taking the weight benefit and going with #6 hoses. I run #6 hose on my Rocket AND have to add a baffle block plate for winter.
 
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