Oil Cooler lines on Lycoming 180HP

[Jim Miller]

I was just looking at a friends Cessna 180 with a STC'd Lycoming 180hp engine. I noticed his oil cooler had only
a 3/8" pipe thread inlet and outlet with 3/8 inch (Dash 6) hoses. When I was putting the 0235 in my RV3 Lycoming
rep told me they are marginally OK for my 108/115 0235. Is he asking for trouble with these small hoses restricting
oil return to engine when vernitherm is activated and all the engine oil is going thru the cooler? Could anyone operating
a certified aircraft with this engine (or experimental) please advise.

Thanks
Jim Miller

 

[8GCBC]

Was the oil cooler on the STC or was it stock? Just curious.

 

[Jim Miller]

Was the oil cooler on the STC or was it stock? Just curious.

That was my question also. It was the small oil cooler like the niagra I had on my RV3. He had those
new factory made long life lines but the b nut sure looked like a dash 6. From looking at some of my
fittings the 3/8" pipe thread can be drilled as a dash 6 bore or a dash 8 bore. Is it possible the new hoses
can be so much thinner a dash 8 could be mistaken for a dash 6? This is a older installation with new
hoses.

 

[Aviator]

I was just looking at a friends Cessna 180 with a STC'd Lycoming 180hp engine.

What's wrong with this picture?

 

[8GCBC]

180

 

[aktango58]

What's wrong with this picture?

you beat me to it!

Doesn't the Cessna 180 have a direct bolt on cooler in the front?

Sort of funny, we get so little 'hot' days like the Okies do, (see, I spelled it as you desire Eaton), probably cause we have fewer FAA folks based here talking and less methane from the local feedlots, that oil coolers really don't seem a big deal. But when it does get warm here...

 

[Superchub]

I'll bet Cessna 170? I have/ use -10 hose.

 

[AK-HUNT]

Doesn't the Cessna 180 have a direct bolt on cooler in the front?

Not on the 180hp stc. Everyone in oklahoma knows that.

 

[Jim Miller]

I was wrong about the airframe it is a 170 but the point is still the same. 180 HP lycoming with dash 6 lines to oil cooler.

 

[Cub Builder]

It's not unusual to find the 3/8 (or -6) lines in this application, but it's also not ideal. While the vernatherm diverts oil to the oil cooler, it doesn't force all the oil through those lines to the cooler. Whatever will go through the cooler and lines does while the rest bypasses the vernatherm. If the oil cooler is small, it may be that the 3/8 lines may feed it near it's capacity anyway. If the oil temps run too hot, I would switch to -8 lines. If that doesn't help, then switch to a larger oil cooler.

When I did the SparrowHawk conversion on my Tomahawk to bring the O-235 up to 125 HP, part of it included the addition of an oil cooler. The STC holder listed several sizes and options for the oil cooler and also listed using either -6 or -8 fittings and lines, but recommended the -8 lines and larger oil cooler for better flow, which is what I used. When I bought the O-320 out of a wrecked Grumman Cheetah to overhaul for my SC clone, it also had a smaller oil cooler than I would want and -6 lines. When I installed it on the SC, it got a much larger oil cooler and -8 lines. The smaller cooler and -6 lines are legitimate, but depending on the application, may not be ideal.

-CubBuilder

 

[Aviator]

Shield(!) your oil coolers to lower your oil temps!

Not to hijack this thread, but plain oil coolers can give you grief if you don't shield them when it gets cold. If the oil congeals in them you could end up with high oil temps when the circulation stops. Depending on internal plumbing, you could also lose all lubrication or even burst your cooler. Continental's non-congealing oil coolers allow some hot oil to circulate through them at all times.

 

[Jim Miller]

Cub Builder
I always thought that only when the engine is cold and the vernitherm open that the oil has two paths, part to engine and part to cooler. When the oil heats up
and the vernitherm closes all the oil goes to the cooler. Lycoming offers a spring and plunger instead of the vernitherm, that acts like a fully closed vernitherm
forceing all the oil to the cooler. I quess the question is can the vernitherm fully close to direct all the oil to cooler.

 

[Jim Miller]

Shield(!) your oil coolers to lower your oil temps!

Not to hijack this thread, but plain oil coolers can give you grief if you don't shield them when it gets cold. If the oil congeals in them you could end up with high oil temps when the circulation stops. Depending on internal plumbing, you could also lose all lubrication or even burst your cooler. Continental's non-congealing oil coolers allow some hot oil to circulate through them at all times.

As I understand it and I confirmed on my 0235 by tracing out the passages from the pump that some oil always goes thru the cooler and when
the engine gets hot the vernitherm closes then all the oil goes thru cooler.

 

[Cub Builder]

You are correct in that some oil is always going through the cooler. That's why taping them off in the winter makes a significant impact in oil temps even with a vernatherm. When I did the upgrade on my O-235, I opted for the $20 plunger and spring rather than the $300 vernatherm and regulated my oil temps in the winter time by taping off the cooler. On my SC with a vernatherm, I still tape off much of the cooler to achieve the desired oil temps.

The spring and plunger allows the oil to bypass the cooler if the cooler gets plugged up. I would assume the vernatherm also allows that to happen. Perhaps someone can confirm or deny my assumption here.

CubBuilder

 

[Jim Miller]

You are correct in that some oil is always going through the cooler. That's why taping them off in the winter makes a significant impact in oil temps even with a vernatherm. When I did the upgrade on my O-235, I opted for the $20 plunger and spring rather than the $300 vernatherm and regulated my oil temps in the winter time by taping off the cooler. On my SC with a vernatherm, I still tape off much of the cooler to achieve the desired oil temps.

The spring and plunger allows the oil to bypass the cooler if the cooler gets plugged up. I would assume the vernatherm also allows that to happen. Perhaps someone can confirm or deny my assumption here.

CubBuilder

You are probably right about the bypass of a clogged cooler, but under normal operation with oil hot doesn't the vernitherm close and direct all the oil thru
cooler? I know my 0235 works this way and the generic diagram I saw of lycoming engine oil systems implies they all are same. I am particularily interested
in this subject because of my RV3. When I first installed the 0235 C1 I put on a oil cooler and a spring and plunger. After flying a few hours in late Aug
I was seeing oil temps low enough to think about taking off the cooler and replacing it with a remote oil filter using the same plumbing including the
spring and plunger. The cooler is now off and the oil filter system is ready to hook-up at next oil change. The spring and plunger will force all the oil thru
the filter and if the filter gets clogged its internal bypass valve will kick -1n or like you say the spring and plunger will allow oil to bypass due to increased
oil pressure from a clogged filter.

My concern for the 170 with the 180 HP lycoming is what happens when the oil is hot, vernitherm is closed, and all the oil exits engine enroute to and
from cooler via -6 lines could there be an issue of oil not returning fast enough for good engine lubrication.

 

[Cub Builder]

The O-235s are a bit different in that (according to Lycoming) you can't take an oil filter assembly from an O-320 and bolt it onto an O-235 without an adapter. However, functionally, they are the same.

The smaller oil cooler and -6 lines were from the Grumman Factory on my O-320, so I would say that it must have met spec. I don't know of the Cheetahs being known for oil pressure issues. Upon tear down @1855 hrs when I bought the engine, I didn't note any issues related to lubrication of the engine. However, it was pretty clear that the engine had been running extremely hot.

-CubBuilder

 

[Jim Miller]

The O-235s are a bit different in that (according to Lycoming) you can't take an oil filter assembly from an O-320 and bolt it onto an O-235 without an adapter. However, functionally, they are the same.

The smaller oil cooler and -6 lines were from the Grumman Factory on my O-320, so I would say that it must have met spec. I don't know of the Cheetahs being known for oil pressure issues. Upon tear down @1855 hrs when I bought the engine, I didn't note any issues related to lubrication of the engine. However, it was pretty clear that the engine had been running extremely hot.

-CubBuilder

What I did because I had no room for any direct bolt-on oil filter (either the straight lycoming or my ECI angled filter adapter) was to buy a high quality
6061 billet racing remote adapter and use the same oil line plumbing as the removed cooler used. Since I was already using a spring and plunger
all the oil goes to the remote oil filter exactly as it was doing with the oil cooler. I am running now with only the screen and no cooler and on a 50 to 60
degree day oil temp is 165 to 170. The filter adapter is mounted and i will hook-up at next oil change. It will be well shrouded with a 2" air blast and
will hopefully give a few degrees of cooling needed during summer.