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Oil temperature question

I've read that Vetterman put the bypass plug back in his RV, removed the vernatherm, and regulates oil temps through oil flow control to the oil cooler by way of a ball valve controlled in the cockpit. Honestly something that I wouldn't mind doing (I actually enjoy full-manual operations in my hobbies, I like to adjust things and be involved in the operation).

I'll keep this in mind. How does yours work, is it like this?

I did just that on my 2+2, works good. On a 25deg. morning I had 180 temps 8 miles from home. And when it's warm out my oil temp is 15deg cooler that with the vern. I'll get a couple pics. tomorrow

Tim
 
I did just that on my 2+2, works good. On a 25deg. morning I had 180 temps 8 miles from home. And when it's warm out my oil temp is 15deg cooler that with the vern. I'll get a couple pics. tomorrow

Tim

Thanks Tim, looking forward to seeing them!
 
Here is what I have, I think it works fine. You just have to pay attention to the oil temp, and keep adjusting until you get where you want it.

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Is the ball valve on the supply or return side of the oil cooler, or does it make a difference?


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In addition to controlling oil temperature, the vernatherm also acts as a relief valve to prevent rupturing your oil cooler from excess pressure. Personally, I would not remove it.
 
Let me chime in here and discuss the vernatherm vs. the spring and plunger. Originally the 0-320 on the cub had the spring and plunger, which made oil flow to the cooler all the time and if the pressure was too great the spring would allow it to bypass. Someone later on named this a "viscosity valve", which I never agreed with. So Piper used the plate on the cooler method to help with oil temperature. Install plate when temperatures were below 40 degrees and remove it above 40 degrees. It was placarded right on the plate.
Then this thing called the vernatherm came along, which was supposed to regulate oil temperature kinda like a thermostat in your car. We found out by doing a lot of testing that the vernatherm is only about 70% efficient and the calls started coming in complaining about hot oil temps. We also found out that most proper size oil coolers will cool the oil in a range, that is 100-110 degrees plus OAT. So if it is 90 degrees and your cooler is doing its best at 110, then the oil temp will be 200 degrees. I got lucky on my cub and have a 102 degree cooler. On the way back from New Holstein, the OAT was 96 and my oil temp stayed right at 198. That was with my valve open all the way. So now back to the vernatherm, being 70 % efficient, my oil temp would have been @215 if I had that setup. If I remember correctly, Tim (previous post with a picture of his valve) reduced his temps at least 15 degrees by replacing the vernatherm with the original setup--spring and plunger. I hope he chimes in here if my numbers on his plane aren't correct.
One other area of oil cooling is worth mentioning. Most setups now on cooler hoses are -8 or half inch. An old time highly experienced mechanic told me to use -6 hoses to slow the flow down, keep the hot oil in the cooler longer and ends up cooling better. I'm convinced in some cases it does work, but in some it didn't make any difference. I'm not sure why, but it is probably related to oil pressure. I have mine set at 76 lbs. at 180 degree temperature.
The above information is not intended to be negative to anyone, but maybe help if you have an oil temperature problem. SD Cubman
 
Tim
Call me Paranoid , but I am a little worried about the fittings you used. The weight of the valve may cause the pipe nipple to crack or brake ? Would it be better to put the valve in the middle of the hose and use steel fittings in oil cooler ?
Doug
 
I prefer to have abundant cooler capacity and control temps by controlling airflow through the cooler. That's been done for years using duct tape or pilot controllable louvers like Van's and Dan's produce. That allows us to operate in a wide range of outside temps and still maintain target oil temps. When temps are on the high side the normal response, assuming engine problems have been ruled out, is to increase cooler size. In CamTom's case he replaced a 7 row cooler with another 7 row cooler. In his shoes I'd have replaced with a 9 row cooler. Actually, with my old -12 I started with a 9 row knowing I could easily reduce airflow in cold temps. My new plane has two 9 row coolers and I'll control airflow with butterfly valves in the outlet ducts. Adjusting airflow may be to restrict flow to raise temps or to slow flow down to improve cooler heat transfer. Finding the correct balance will be simple enough. It makes more sense to me to have adequate or excessive cooler capacity and control airflow as opposed to controlling oil flow. Different strokes. Interesting topic.
 
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Spin on oil filter with plunger and spring?

SPIN ON oil filter CUB CRAFTERS aa.JPG Can you use a plunger and a spring with a spin on oil filter set up? All of the oil filter adapters that I have seen, show a vernatherm as part of the set up. I currently have a plunger and a spring that works fine on my PA-18 180 but I would like to have a spin on filter.
 

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Yes, you'll need a vernatherm plug. The adaptor mfgrs make them for viscosity valve users.
 
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In most cases, I believe you can. I have filter adapters and simply remove the vernatherm, remove the top part of the vernatherm, usually a clip or snap ring holding it in the base. Then just re-install the base. Or B&C has the plug that takes the place of the vernatherm.
Returning to the subject of controlling oil temps. There are two completely different scenarios. Using louvers, air control valves etc is typically used to increase oil temps. For cold operation. Installing the spring and plunger setup is usually for lowering temps. I have received many calls about oil temps being too high, never how can I increase the temperature.
 
Common sense is to facilitate adequate cooling in the warmest OATs you'll
see and then adjust for cooler temps.
 
Tim
Call me Paranoid , but I am a little worried about the fittings you used. The weight of the valve may cause the pipe nipple to crack or brake ? Would it be better to put the valve in the middle of the hose and use steel fittings in oil cooler ?
Doug

Donno Doug,I thought the same thing when I put it together. I have been keeping a close eye on it and it seems to be holding up fine, time will tell. I did use steel fittings, and a brass nipple, all I had at the time.

Tim
 
Donno Doug,I thought the same thing when I put it together. I have been keeping a close eye on it and it seems to be holding up fine, time will tell. I did use steel fittings, and a brass nipple, all I had at the time.

Tim

Got to be a boilermaker. A pipefitter wouldn't do that. [emoji41]


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Ok, oil analysis kit ordered.

I'm going to pull the oil filter adapter and check to see that nothing is stuck or gunked up back there. This is what I've found for the gasket (lycoming 06b23862):
textron-lycoming-06b23862-gasket-oil-filter-adapter.jpg


Here's what I've found that the back of the adapter (lycoming 77852) looks like:
4_zps8vitoggt.jpg


Seems like large openings in the adapter covered by small holes in the gasket. I'm ordering a new gasket, can someone verify I have the right part number? I'm also looking for a digital SSP 885-2 if anyone has one they can email me.

I thought about just pulling the vernatherm and going with a ball-valve, but I think I'm going to hold off on that step until after I check this stuff out. I'd like to make sure I understand what the problem was, and don't want to change too much at once. I found most of the parts I would need to make that mod if/when the time comes, though.

Thanks!
 
Anyone have the part number for the "viscosity valve" for an O-320?

Eddie,
Here's what I found for the part numbers:

Plunger: 62415 ($31 at Spruce)
Spring: 69436 ($45 at Spruce)
Crush washer: 76510 ($2 at Spruce)

And it looks like you just reuse the plug that's currently installed to hold the spring/plunger in the hole.
 
Ok, oil analysis kit ordered.

I'm going to pull the oil filter adapter and check to see that nothing is stuck or gunked up back there. This is what I've found for the gasket (lycoming 06b23862):
textron-lycoming-06b23862-gasket-oil-filter-adapter.jpg


Here's what I've found that the back of the adapter (lycoming 77852) looks like:
4_zps8vitoggt.jpg


Seems like large openings in the adapter covered by small holes in the gasket. I'm ordering a new gasket, can someone verify I have the right part number? I'm also looking for a digital SSP 885-2 if anyone has one they can email me.

I thought about just pulling the vernatherm and going with a ball-valve, but I think I'm going to hold off on that step until after I check this stuff out. I'd like to make sure I understand what the problem was, and don't want to change too much at once. I found most of the parts I would need to make that mod if/when the time comes, though.

Thanks!

Can anyone verify the correct gasket part number for me before I hit the order button?
 
This is what I've found for the gasket (lycoming 06b23862):
textron-lycoming-06b23862-gasket-oil-filter-adapter.jpg


Here's what I've found that the back of the adapter (lycoming 77852) looks like:
4_zps8vitoggt.jpg


Seems like large openings in the adapter covered by small holes in the gasket.

I found a picture of the accessory case - looks like this gasket isn't that far off:
IMG_2614-XL.jpg


I'd still like a dummy-check from someone that'd know before I order it and get ready to do some tear-down though.

Thanks!
 
Dug out my old vernatherm to get a picture of the face:
251988E7-088B-4AD4-A5D6-F3727EDFAB8F_zpsvshiokii.jpg

F67C0DC9-6F9C-4565-A896-5E63E90FF747_zpspkyrjnb6.jpg


Looks like I remembered it right, 360 deg witness mark. This one flew in the engine for about 200 hours before I replaced it, hoping to fix the high oil temp problem. The new one has the exact same symptoms as the old one did. I'm going to risk it with the old lady and boil this thing in the kitchen tonight to measure for proper growth - but the witness mark tells me that it was growing to the right length otherwise it wouldn't have made contact. Hopefully I don't get in trouble, haha!

Does anyone have a copy of Lycoming SSP 885-2 they can email me? Also, can anyone verify that this is the correct filter adapter gasket part number: 06b23862
 
I used to have high oil temps (200-210 ish). Changed cooler to 9 row. Some improvement. Also used to use a qt of oil every 4-6 hours in O-360. Changed cylinders and now oil temps fine (180). Now I have to cover 1/3 of the oil cooler as soon as temps drop below 40 or so. Speculate that excessive blow by was heating oil.
 
I'm going to risk it with the old lady and boil this thing in the kitchen tonight to measure for proper growth - but the witness mark tells me that it was growing to the right length otherwise it wouldn't have made contact. Hopefully I don't get in trouble, haha!

Well, the thing grew to larger than spec. Seems like a waste of $325 now to have replaced it at annual. Oh well.

I used to have high oil temps (200-210 ish). Changed cooler to 9 row. Some improvement. Also used to use a qt of oil every 4-6 hours in O-360. Changed cylinders and now oil temps fine (180). Now I have to cover 1/3 of the oil cooler as soon as temps drop below 40 or so. Speculate that excessive blow by was heating oil.

Thanks for the info! Hopefully an automotive-style compression test will answer that question. I'll do that test soon, too.
 
Well, I fell way behind on the suggestions everyone gave me here. I still have yet to do an automotive compression test, but I'm going to knock that out after work on Wednesday.


Today I had some time at the hangar and some help from a friend, so I fabbed up a new cowl exit to see if I could help in the airflow department in case that was the problem. I went down this path because many folks have suggested that my cowl exit area wasn't large enough to vacate the lower cowl area and that airflow was likely my problem.


Here's how the plane came:








And here's what I made:














The before/after was change in ~0.35 inH20 difference between each side of the baffles. This had a measurable difference in temps, at ~10-15 deg across the board for CHT and oil temp. Without had CHTs between 320-350 and OT of 195, with the mod had CHTs between 305-335 and OT of 185.


Both scenarios flown at 135 mph, 2400 RPM, leaned for cruise, 65 deg F OAT, and a difference (high pressure to low pressure sides of the baffles) of 3.85 inH2O before and 4.2 inH2O after the mod.


Even though improving the air flow improved the cooling, I shouldn't be hanging near 185-195 deg F oil temps in these conditions. Especially while CHTs are so close to 300 deg in 65 deg F OATs. Back to troubleshooting the oil system. Next step is an automotive compression test (I have the tool). Pending the good results of that I'll be due an oil change, so I'm going to get new hoses, send my oil cooler off for a flush, and send my oil filter adapter to somebody to check the vernatherm seat.


More to follow!
 
I think that's what a vernatherm is supposed to do, not direct oil to the cooler until it reaches 185 and the plunger expands.
My Pitts has a vernatherm and I'll get 185 degrees oil temp at 30 degrees OAT.
My Cub doesn't have a vernatherm and I have to tape over the coolers to keep the temp up at 70 degrees OAT.
 
A good friend shared his temperature numbers from a similar flight to mine (they were pretty similar) and brought me back to reality. I think it was just airflow.

I'm still going to do the automotive compression test this week and send an oil sample for analysis. I'm also going to clean up my sheet metal duct and reinstall for some long-term data trends.

Other than that I'm just going to put gas through the engine and monitor temp trends. I'll keep a close eye on it as temps increase, but if I can stay around 220 on a summer day around here I'll be happy.


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