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Posted

Just trying to understand my engine more and i cant seem to find a answer anywhere. 

I'm curious of the flow of oil through the engine. After going through the oil pickup screen in the sump I take it it goes through the oil pump then from there I'm a little lost. Does it go through the oil filter then oil cooler then into the engine. Or sump, pump, cooler, filter then into the engine.

 

Thanks

Posted

Sometimes the POHs have the basic oil flow characterized by a drawing... similar to the electrical schematics...

The older the plane, the more simple the drawings...

The Best way to get good drawings specific to the engine... right from the manufacturer’s website...

Some drawings may actually cost money... so in that case EBay can be your friend... finding old printed manuals for the engine for a few bucks...

PP thoughts only, not a mechanic...

Best regards,

-a-

So to test my answers I tried to look these up...

My 70s POH didn’t have a drawing of the oil system.... 

My 70s engine manual had all the parts listed, but no oil flow drawing....

My 90s Manual of flight.... had a simplified drawing that didn’t mention oil temp control or oil filter or even the finger screen... the book was from a Cessna Pilot Center or CPC...

 

Great question, good to know the answers, stand by for somebody with actual knowledge...   :)

Best regards,

-a-

Posted

dff20ca9821ef970c349850d98508d11.jpg

By the looks of this diagram it looks likes the oil goes from the sump to the pump, from the pump if the temperature is below 180° F some will flow trough the oil cooler and the other directly to the filter. Onces the temperature raises above 180°F and the vernatherm closes all oil is forced trough the cooler then the filter and finally the engine.. This is my understanding of the system i could be wrong... Hope this helps.


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Posted
15 minutes ago, siu1526 said:

dff20ca9821ef970c349850d98508d11.jpg

By the looks of this diagram it looks likes the oil goes from the sump to the pump, from the pump if the temperature is below 180° F some will flow trough the oil cooler and the other directly to the filter. Onces the temperature raises above 180°F and the vernatherm closes all oil is forced trough the cooler then the filter and finally the engine.. This is my understanding of the system i could be wrong... Hope this helps.


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Thanks for the diagram!!! Definetly answers some questions!! I've been having high oil temp issues and was wondering how its possible for the cooler to get plugged up.

Posted

1) Screen on the pick-up

2) pump, gear pump style

3) Vernatherm (temperature controlled valve, when cold, oil goes past the cooler...)

4) oil cooler

5) Temp sender

6) Filter, with pressure relief valve, in case the filter gets clogged.... or finger screen in case no oil filter has been added.

7) Pressure sender

8) T&P adjusted and filtered, oil gets delivered to the Oil gallery which distributes the oil to all of the bearings...

9) At the end of the oil gallery... is the adjustable oil pressure regulator...

10) everything that allows oil out of tight spaces drips back into the sump...

11) Not mentioned... the prop gov... the gov has its own gear pump to produce pressure, and a valve to send pressure to the prop... all driven by an rpm controlled valve that uses fly-weights to determine rpm...

Description, based on SIU’s graphic depiction above... :)

Best regards,

-a-

Posted
16 minutes ago, Spuderman1 said:

Thanks for the diagram!!! Definetly answers some questions!! I've been having high oil temp issues and was wondering how its possible for the cooler to get plugged up.

All kinds of exhaust related sludge has a tendency to fall out of solution as the oil speed slows down...

Over the years, an oil cooler can have its lines blocked by sludge, It helps to have an IR thermometer or IR camera to see the effect...

It is pretty easy to clean out a mildly blocked oil cooler... there are also people that OH them...

Check the costs of a new replacement... it might cost less than the OH...

What usually fails is the vernatherm... that device was designed to be easily removed, cleaned check and put back...

Testing the vernatherm involves putting it in water and heat the water towards boiling... note the temp when the vernatherm opens/closes....  as they age, they lose their skill...

A cold vernatherm doesn’t send oil to the cooler... as the oil warms up to the set temp... the vernatherm starts to direct oil flow to the cooler... the hotter it gets, more flow is diverted through the cooler...

If the vernatherm isn’t sending oil to the cooler, the oilT will start to rise...

So check the operation of the vernatherm first... solvent washing of the oil cooler may be helpful, both inside and outside.... check the fins for their condition as well... check with your mechanic on how best to handle these tasks.

PP thoughts only, not a mechanic...

Best regards,

-a-

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