Oil cooler burst pressure

[Charlie Sisk]

As to not high jack the other oil threads, I'll start this one. When comparing oil filters, burst strength always comes up. Champion and Tempest are 600 psi or so. The lowly Wix 51452 is only 420 psi. But...aint there always a "but".... what about the oil cooler ? Here are two references to oil cooler psi burst ratings.

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Airframe and Powerplant

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Seems 400 psi is the number. So why are we so concerned about the oil filter pressure rating, and not about the oil cooler ? I always preheat below 50*F, I dont like to wait.
If either oil filter or oil cooler turn loose, its gonna be a bad day. But a filter would be much faster to change.
Thoughts ?
Charlie

 

[Scott Hersha]

Maybe I’m visualizing the oil flow path incorrectly, but the burst limit on the oil filter refers the the pressure inside the can when it becomes clogged, not the high oil pressure downstream (oil cooler). If the can pressure gets too high the pressure relief should open and downstream pressure remains more or less normal - right? Or am I wrong about that? Unless the oil filter bypasses large amount of trapped gunk into the downstream flow path and then clogs the oil cooler - and then you have oil cooler burst possibilities.….. maybe.

 

[gasman]

In this sketch that I snipped from one of Dan's posts, you can see if you were using a filter with a built in 8-11lbs bypass, It would have to fail, and then the bypass in the adapter that is set to 12-14 lbs would have to fail. And then the adjustable relief (back to the sump) would have to fail before any pressure in the system would exceed the pressure set by the relief valve.

There are only two ways I see pressure exceeding the relief valve....
1. The failure of the filter element and the element clogging the relief valve.

2. Using a single grade 50wt. oil in a COLD climate, starting the engine and immediately running it to a high rpm..... And maybe not even then. Does anyone want to test that scenario?

There is one more way that you can exceed the working pressure of a spin on oil filter.... If you install a remote filter and cross the lines to the filter and you install an anti-drain back filter.

 

[Toobuilder]

The filter (and adapter) relief valves are set to differential pressure (In vs. out) The can sees system pressure, same as the bearings.

 

[Scott Hersha]

In this sketch that I snipped from one of Dan's posts, you can see if you were using a filter with a built in 8-11lbs bypass, It would have to fail, and then the bypass in the adapter that is set to 12-14 lbs would have to fail. And then the adjustable relief (back to the sump) would have to fail before any pressure in the system would exceed the pressure set by the relief valve.

There are only two ways I see pressure exceeding the relief valve....
1. The failure of the filter element and the element clogging the relief valve.

2. Using a single grade 50wt. oil in a COLD climate, starting the engine and immediately running it to a high rpm..... And maybe not even then. Does anyone want to test that scenario?

There is one more way that you can exceed the working pressure of a spin on oil filter.... If you install a remote filter and cross the lines to the filter and you install an anti-drain back filter.

Thanks for the drawing. Obviously the cooler is upstream of the filter normally - after the vernatherm has seated, so gunk being dumped by a failed oil filter heads for the engine/bearings. Oil cooler should be fine unless it gets clogged somehow and the vernatherm doesn’t allow a bypass of the cooler.

 

[Avanza]

Thanks for the drawing. Obviously the cooler is upstream of the filter normally - after the vernatherm has seated, so gunk being dumped by a failed oil filter heads for the engine/bearings. Oil cooler should be fine unless it gets clogged somehow and the vernatherm doesn’t allow a bypass of the cooler.

When I bought my plane it had an air wolf remote oil filter, champion 48108 and about 500 h engine time.
First time I changed oil filter I noticed that the black rubber membrane behind the holes in the oil filter was cracked.
The next time I changed the oil filter the rubber membrane was cracked again.
I read the superior engine manual and came to the conclusion that the oil flow was reversed through the oil filter.
After I reversed in and out hoses the next oil filter had no damage. So the filter seems to have a built in safety system not to burst.
If you run your engine with 50 wt oil in cold weather (high altitude) the oil cooler will clog up and stop oil flow.
This will force the wernatherm valve to bypass the oil cooler and the engine oil temp will rise quickly.

Good luck