Honeywell/Keller vs. VDO Oil Pressure Probe

[Pat]

Hi,

I have a 912 80hp with the old style VDO Oil Pressure probe. I have recently installed a GRT EIS 4000. Unfortunately, my EIS unit was wrongly configured by GRT Avionics to work only with the new Honeywell/Keller probes. I checked and the Keller probe is 400€ 😞 😞.

Also it has a different thread. 

 

Is there any alternative probe that is less expensive and is the same style as Honeywelll/Keller so it works with my EIS 4000? 

 

Otherwise I have to ship my EIS4000 back to the USA for reprogramming (which can take weeks). 

 

Thanks a lot! 

 

[KRviator]

The Dynon Kavlico probe may be an option? I'm really surprised there's a difference between resistance across manufacturers. What's the probe part number there've told you to use?

You should be able to reconfigure your EIS yourself, I'd be very surprised if they've locked that functionality.

[Underwood]

Type "oil pressure sender in to Ebay (probably amazon also) and you'll find many oil pressure senders both VDO type and the solid state types equivalent to Honeywell.

I bought one of the cheapo Solid state senders to link to an MGL EMS and it worked fine.

Have to ensure you get the correct thread (or fit an adaptor) and pressure range.

 

[skippydiesel]

Probably have sell you child into slavery but you could price out a Rotax oil pressure sensor😈

[Pat]

It seems Honeywell/Keller are identical electrically (4mA = 0.75 bar 20mA = 10.75 bar). 

 

@Underwood do you remember the sender you bought? 

[Underwood]

https://www.ebay.co.uk/itm/387325211088?_skw=100psi+10bar++Stainless+Pressure+Transducer+Sensor+Oil+Fuel+5v&var=654583436388&itmmeta=01JTXK10RAC4KBZ4XXCH3HSA0J&hash=item5a2e61b1d0:g:jRUAAOSwLy9iC3sT&itmprp=enc%3AAQAKAAABIFkggFvd1GGDu0w3yXCmi1faiUPSueSOxbzWx0BagonCFC4mNVy8GwHwiPfwv7ku%2FFh%2FYNlWYeIvZf00lLcYfUtx8IlH%2FLkwkI1k43SlgX1ee5GGHcK5oOqqDJufyV0qIEl4kyuegvTh9OKhCtU5ZWuEQK%2FWKajxeTX%2FUsFBoQW1wtCBD8LEWfvM7FfYtD2p7xMS0LW1sjUTjAStTCKQ9j9IGQNrwJTnLDQYJhfhqgAhQzllKlm1l6AaqqQltIflrcbpNIdXms4ZmkgnYjOSog7RajI7h6z%2FZSEGUOIliyrm8IQuzjsW7YKJe7mDY0u3HL4zHtpKvYlcKDxF3W3jz7EduUFUbmLpQEwdvv1utWyr%2BxaCqLpBIFlaa8qpKlpCQA%3D%3D|tkp%3ABFBM3o2Es9dl

[KRviator]

Have a read of this - it tells you how to get into the setup menu on the EIS so you don't have to send it back to GRT to reprogram your sensor definitions for the sensor you have.

Should be able to sort out your EIS yourself and save yourself a few quid.

Troubleshooting-Guide.pdf

[Pat]

23 hours ago, KRviator said:

Have a read of this - it tells you how to get into the setup menu on the EIS so you don't have to send it back to GRT to reprogram your sensor definitions for the sensor you have.

Should be able to sort out your EIS yourself and save yourself a few quid.

Troubleshooting-Guide.pdf 232.82 kB · 6 downloads

Thanks a lot! Unfortunately that doesn't specify how to make the GRT EIS 4000 accept the old style VDO resistance oil pressure probe readings. So I'll have to find the new style Honeywell/Keller probe.. 

[Pat]

I believe my 20+ year old 80hp 912 uses a 1/8-27 thread for the oil pressure probe. I found this (Honeywell?) which is also 1/8-27 thread, but otherwise it is the new style 4-20mA sensor. Is that a suitable option? 

 

EDIT: Disregard, that one isn't 4-20mA but 5V. 

Edited Sunday at 10:27 PM by Pat

[IBob]

I believe Rotax went away from the VDO unit as they are prone to failure: I have seen several replaced, and I don't get around that much.
Pressure transducers or transmitters with 4-20mA output are a long standing industrial standard.
Part of the benefit is that they return an accurate value regardless of how long the connecting wire is, which Voltage outputs don't (4mA anywhere in the loop will be 4mA, but 5v out there can be a lot less back here due to resistance of the wiring. However, that will not be a factor in light aircraft installations. I believe Rotax went looking for a more reliable replacement, and these industrial standards proved to be it.)
They come in a number of standard ranges, one of which is 0 to 10bar. I don't think I've ever come across 0.75 to 10.75bar. That surprises me a bit and I don't understand why they would be 'nonstandard': typical ranges would be 0-10, 0-15, 0-25 etc, always round numbers.
My Heavy Maintenance manual states 0 to 10bar and mentions either replacing the pump cover or recutting for a M10 x 1 thread (!) if upgrading sensor type. However this section of my manual may not be the latest version.


There will be lots of 0-10bar sensors out there, but it will be a bit of a punt as to which will prove reliable in the Rotax environment of temperature, vibration and possibly pulsing pressure from the pump. If going that way, I would definitely be inclined to stick with the Rotax recommended unit.
That or go with what you've got and reconfigure the EIS.

[IBob]

For anyone interested in the (nonstandard) 0.75 to 10.75bar bizzo, here is Dynon digging into it:
https://forum.flydynon.com/threads/rotax-oil-pressure-pn-456180-definition-wrong.11767/

 

The final lines state Rotax 456180 is a standard 0 to 10bar unit, confirmed by Dynon physical testing. Which makes every sense.