Oil pressure sensors - why not screw directly into engine?

Brian Vickers · #1 12-07-2009, 07:16 PM

Education needed

Why is it bad practice to screw the oil pressure transducer directly into the accessory case? I am about to do what appears that everyone else does and mount the oil pressure sensor (VDO brand) OFF of the engine (not on the engine). It would sure be nice to screw it into the appropriate hole in the accessory case instead of routing hoses and mounting the sensor. The steel AN oil pressure hose fitting from Vans has a restrictor hole, just like the sensor. Is the issue direct engine vibration and therefore shortened service life? Transducer break off and cause catastrophe? The Firewall Forward book says ?the electric sensor is screwed into the engine.? Sorry for such a basic question but my search of the archives didn't turn on the light bulb. I'd sure like to know what caused the trend toward remote mouting.

Thanks

rv6rick · #2 12-07-2009, 07:22 PM

Hi Brian,

Yup......you answered your own question.

Giver 'er a shot....let us know how you make out

.

Quote:

Originally Posted by Brian Vickers

Education needed

Why is it bad practice to screw the oil pressure transducer directly into the accessory case? Is the issue direct engine vibration and therefore shortened service life? Transducer break off and cause catastrophe?

Thanks

rocketbob · #3 12-07-2009, 07:28 PM

Best ask someone with a Jabiru...they've been doing it with success for years.

David-aviator · #4 12-07-2009, 08:07 PM

Quote:

Originally Posted by rocketbob

Best ask someone with a Jabiru...they've been doing it with success for years.

Yep, and they work ok on the Subaru block as well.

But an IA told me years ago don't screw it into a Lycoming block. Evidently, he'd seen one break resulting in a gross oil leak.

I believe it is prudent to use the Van's manifold.

Ironflight · #5 12-08-2009, 06:21 AM

Now that I have changed it to a remote mount, I can say that Louise's RV-6 had the sensor screwed directly into the engine (on one of the front oil gallery ports) when she bought it, and it was probably there for 19 years and 2500 hours without a problem. I moved it because we had a new (EFIS) sensor go erratic after about 50 hours, and I decided that it might have been vibration, so why not eliminate that possibility.

YMMV

Brian Vickers · #6 12-08-2009, 09:03 AM

Thanks guys,
Last night I had one of those pondering work sessions (no tools used). I'm going to remote mount it and move on. Thanks again for the comments.

David Clifford · #7 12-08-2009, 02:35 PM

My IO-540 V4A5 came out of a 2001 Maule and the Rochester oil pressure sending unit was screwed into an oil port on the accessory case. Seeing as how it was good enough for a certified plane application, I intend to leave it there for simplicity. I will locate the fuel pressure sender off the engine though. When we built the Cozy MKIV, we installed an AirWolf remote oil filter system, so It was a simple solution to mount it off the engine.