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Remote Mount Oil Pressure Sender

todehnal

Well Known Member
I have decided to install the remote mount kit for my oil pressure sender, during the build. I am trying to select a location on the firewall for the sender. It looks like we have two unused K1000-3 plate nuts on the upper firewall, just above and inboard of the battery. Thinking about using one of those. I noticed a thread by JPILOT, and it looks like he mounted his near the bottom, something about oil drain. Is there a problem with mounting the sensor above it's original location on the engine?

Also, Lockwood send me an alternative elbow fitting, that will start the routing of the hose, from the port on the engine, towards the rear, rather than straight out. This fitting appears to not need a clamp on the hose, other than the fire sleeve. Any guidance on the installation would be greatly appreciated. As a builder, I have been very reliant on Van's well done, step by step, plans set. When I get off into the rest of the world of homebuilts, and left to my own interpretations, I am easily snowed!

To those of you who have "been there and done that", I would appreciate your help on this one.

Tom
 
I've mounted mine on a bracket and clamp next to the battery. I have made up the hose and plan to run it under the right hand cylinders and secure it with clamps. However like you, this is new territory for me, so I'm open to suggestions.

8778089645_a3a14deae5.jpg
 
I see 80 PSI plus on my gauge, so I think AN fittings would be safer than a clamp. A pinhole fitting would also restrict the amount of oil in case the hose connection did fail. I used an Adel clamp to fasten my sender to the firewall, but your bracket looks much better. Just a thought.

Jim
 
The Lockwood kit

The kit that I got from Lockwood included a fitting for the engine port that is a pinhole fitting, restricting the oil flow in case of a hose, or sensor failure that would allow oil to escape.

The hose fitting that is in the picture on the second post is what Lockwood supplies. The hose that is supplied, is an Aeroquip 300psi rated hose. They have been installing these kits on all of the Rotax powered airplanes they support, and have had no issues with the clamps. Let's see what others have to say about it.

I discovered that the two K1000-3 nut plated that I spoke of in the original post, are used for the coolant expansion tank, but I still may be able to hang the sensor on the inboard nut plates with the expansion tank strap.

Hope others chime in............Tom
 
Can someone specify the partnumber for the hose kit from Lockwood.
I have mailed them twice but they do nit answer
 
Contact for Lockwood

Jack, they have 2 different kits for RV-12's. One for the original sender, and a different one for the Honeywell replacement senders. They sent me the wrong kit, and I had to call back and have additional parts sent. I got the one for the Honeywell, which has the item code of EAPSIRK, and a description of "Pressure regulation kit, use with V360-043 (fuel) or V360-430 (oil), not included. Not sure what email address you are using. I have the following: [email protected]

Last resort, call them. Tell them which sender you have, and ask for the relocation kit. The number is 863-655-5100, ask for parts, or fax to 863-655-6225. They are in Florida and on Eastern Daylight Time. Hope that helps
 
Oil sender location

I've mounted mine on a bracket and clamp next to the battery. I have made up the hose and plan to run it under the right hand cylinders and secure it with clamps. However like you, this is new territory for me, so I'm open to suggestions.

8778089645_a3a14deae5.jpg

Here is my experience in moving the oil sender.
I do like your location better.

Tony
 
I got the Lockwood kit. I used the upper outboard bolt that attaches the Skyview engine module to the firewall. I attached a adel clamp to that to hold the relocated sensor. Works fine. If memory serves, I think I went to the hardware store and got one 90 degree fitting that wasn't in the kit. That may vary based on how you route your line. Also, and I don't know if it was really necessary, but I charged the line with oil as part of connecting it all up. Note that your oil reading will be slower to come up after engine start - will take a few seconds.
 
Last edited:
Thanks for the link Tony, I didn't know you'd moved yours. I looked at taking the hose over the top, but there are already a lot of hoses and the plug leads crossing there and potentially rubbing on each other. Going underneath was a shorter route and less congested. It puts the hose closer to the muffler, but still fairly well clear. I discussed it with my tech counsellor and he thought it was OK. I was going to put the bracket on the firewall shelf with the sender horizontal, which seemed a neat arrangement to me, but he felt that might not provide enough strain relief. With the sender mounted where it is now, the hose curves up from below into the fitting and has plenty of flexibility. Where it passes under the cylinders I'll secure it with Adel clamps. I don't know if this approach is better or worse than any other, but I guess time will tell.
 

I see 80 PSI plus on my gauge, so I think AN fittings would be safer than a clamp. A pinhole fitting would also restrict the amount of oil in case the hose connection did fail. I used an Adel clamp to fasten my sender to the firewall, but your bracket looks much better. Just a thought.

I agree.

Does the kit Lockwood supply's have a push on hose barb fittings for the hose Like the one in the photo)? :eek:
 
I agree.

Does the kit Lockwood supply's have a push on hose barb fittings for the hose Like the one in the photo)? :eek:

Mine is the Lockwood kit, and it comes with those barbed fittings. The fitting at the engine end has a pinhole restrictor. The hose is a push fit and secured with Oetiker clamps.
 
I agree.

Does the kit Lockwood supply's have a push on hose barb fittings for the hose Like the one in the photo)? :eek:

The oil pressure sender issue goes back a couple of years at least. Many RV-12s have the Lockwood kit installed. Here is a post from a couple years ago that shows the content of the kit, including the barbed fittings and Oetiker clamps to secure the pressure hose.
I don't remember if anyone contacted Van's with the oil sender location as a problem. Since it is a Rotax part, installed by Rotax, I doubt Van's would have assumed a responsibility or provided a recommendation.

Tony
 
The oil pressure sender issue goes back a couple of years at least. Many RV-12s have the Lockwood kit installed. Here is a post from a couple years ago that shows the content of the kit, including the barbed fittings and Oetiker clamps to secure the pressure hose.
I don't remember if anyone contacted Van's with the oil sender location as a problem. Since it is a Rotax part, installed by Rotax, I doubt Van's would have assumed a responsibility or provided a recommendation.


I am aware of the perceived issue... I say perceived because I have never seen any level of evidence that shows that the sensor mounted on the engine has any effect on longevity.
I am aware of a few sensor failures, but there has never been any evidence to suggest that remote mounting would have prevented those failures. It seems that most of the frenzy to change the mounting location resulted from the recommendation of Lockwood. Is this because they have data they haven't shared (I have an open line of communication with a couple of the key tech. people there), or because they were searching for a solution to sensor failures and thought that sounded like a good idea?
My original question was based on a bit of surprise that the install kit uses hose barbs and clamps for a rather critical hose installation. That in it self is not bad but it does imply what type of hose is probably being used.
Personally I see this mod as attempting to cure a possible, but uncertain disease, with a potentially fatal one.
All of the critical hoses (oil and fuel) on the RV-12 FWF are fire sleeve protected, which gives them a high level of protection against abrasion/wear through, etc. If this particular hose is not well protected (I don't know whether it is or not) it induces a critical (and maybe un-necessary) hose that is highly dependent on being properly routed, restrained and protect, to prevent the hose from being compromised over time. If it ever is compromised, it will be a serious event.
 
As I recall - -

there were 2 reasons for remotely mounting the sender. 1) The high cost of the sender, and the 'possibility' that vibration/failure was an issue. 2) The fluctuating reading on the display. The remote kit stabilizes the oil pressure readings by having a tiny port for the oil to go thru. I made my own, and used aeroquip blue hose. No problems so far.
 
Fire sleeved

The Lockwood kit's hose is fire sleeved. I switched locations for two reasons: As a possible way to prevent a failure, and as a cure for the continuous rapidly changing oil pressure readings. Even if I wasn't watching the Dynon the continuous fluctuation would catch my eye all the time.
The first reason may or may not have been successful-- the original sender is still working in its new location-- but the second certainly was. The pressure readings are now steady and the Dynon doesn't keep reaching out and grabbing my eye. That alone was worth the change, which I did at the first ACI.

Wayne 120241/143WM
 
I am aware of the perceived issue... I say perceived because I have never seen any level of evidence that shows that the sensor mounted on the engine has any effect on longevity.
.

I have zero Rotax experience, but have personally seen several cantilever mounted pressure transducers fail thru the pipe thread mounting on Diesel engines, and I believe that is the primary reason to remote mount them on aircraft. Especially on amateur built aircraft and the wide variety of components that may be used, you just don't know when something is going to resonate...or not resonate.
Tim
 
Tim

I still have the engine mounted sender. You mentioned a failure of a sensor. Was it a Honeywell or one of the older types that looks like a small can? Intuitively the Honeywell seems to have a smaller moment arm and should be less susceptible.

Rich
 
I am aware of the perceived issue... I say perceived because I have never seen any level of evidence that shows that the sensor mounted on the engine has any effect on longevity..

My original sensor lasted 40 hours mounted on the engine. My current sensor is at 170 hours mounted on the firewall. Both Honeywell.

I do agree with your thoughts on everything else, but have had very good luck so far with the relocation. It is one more hose to replace every five years.
 
I have zero Rotax experience, but have personally seen several cantilever mounted pressure transducers fail thru the pipe thread mounting on Diesel engines, and I believe that is the primary reason to remote mount them on aircraft. Especially on amateur built aircraft and the wide variety of components that may be used, you just don't know when something is going to resonate...or not resonate.
Tim

I agree it is not a good practice to direct mount a sensor to a traditional aircraft engine (Cont. / Lyc.), but the 912 Rotax is a very different animal (and hugely different from a hard pounding diesel engine).
 
.....The remote kit stabilizes the oil pressure readings by having a tiny port for the oil to go thru. ......

Is it possible to install a "tiny port" in line with the present sensor, just to stabilize the readings? Just asking..........
 
My original sensor lasted 40 hours mounted on the engine. My current sensor is at 170 hours mounted on the firewall. Both Honeywell.

I do agree with your thoughts on everything else, but have had very good luck so far with the relocation. It is one more hose to replace every five years.

I understand that is the case with a number of RV-12 builders, but a couple or three data points doesn't prove anything. They could have just been sensors with a manufacturing defect.

Now if you had a second one fail at low hours in the original location (low odds of a customer getting two bad ones) and then installed the third one remotely and it worked fine for many hundreds of hours, then we would have something to go on.
 
Is it possible to install a "tiny port" in line with the present sensor, just to stabilize the readings? Just asking..........

As I have mentioned in the past, I think the snubbing action gained by remote mounting the sensor is due to the hose.
All hose has some level of expansion due to pressure... some more than others.
 
Oil Presure Sensor Failure!

Fact: Right now on all engine mounted oil presser sensor RV12s weather Skyview or D180 the oil pressure indication fluctuates +-8 tp 10 psi.
Fact: When the the sensor is remotely mounted to the firewall with the Lockwood kit this fluctuation goes away.
IMHO: After mine failed I did some detective work and found out there were more failures than people like to think.:cool:If you go back and search all the postings here you can see failures of the oil sensors along with a lot of discussion as to why this was occurring. Mine failed at 100 hours, now 341 hours later after moving the sensor to the fire wall, no failures. When I bought my new sensor I inquired how many they sell and the reply was we can hardly keep them in stock! If one wanted to for the purpose of this discussion call Lockword and ask I think you would be pretty surprised as to how many sensors they sell every year. At $340 per sensor I didn't mind at all paying the $70 to move mine to the fire wall. I don't think Lockwood Aviation would carry a remote mounting kit in stock if the didn't see a reason to have it. If anyone would know they would.;)This is whats great about Experimental airplanes, if you perceive a problem that may cost you a reoccurring large amount of money and some one comes up with a fix for this problem than you can put the fix on your airplane if you so choose. As I have said before, " You Make the Call".:D
 
I believe that - -

if the remote kit did not need the tiny orifice to dampen the oil pressure fluctuations, it would not have been installed. The tiny orifice is what stabilizes the readings. The hose likely might take a little of the problem away, but not enough. Scott - 98% of the time I agree with you, so keep it up. Thanks !
 
if the remote kit did not need the tiny orifice to dampen the oil pressure fluctuations, it would not have been installed. The tiny orifice is what stabilizes the readings. The hose likely might take a little of the problem away, but not enough. Scott - 98% of the time I agree with you, so keep it up. Thanks !

I believe the tiny orifice is to preserve the oil in case of a oil line failure. You have a little time to get on the ground before you loose all of your oil if your pressure goes to zero.:)
 
Remote oil pressure sensor

I built a PulsarXP back in 98 and went through 3 sensors in 125 hours. After remote mounting on the firewall I put 400+ hours on it without a problem.

I can say for sure remote mounting made a huge difference.

Building a Just Highlander now and will definitely remote mount the oil pressure sensor.

Gary
 
Colin - -

it would help some there also, but since I built my own remote, I can tell you for absolute certain, that without the tiny orifice, the readings are not stable. I know because I had to re-do mine after finding that out.
 
All of the critical hoses (oil and fuel) on the RV-12 FWF are fire sleeve protected, which gives them a high level of protection against abrasion/wear through, etc. If this particular hose is not well protected (I don't know whether it is or not)...

The hose supplied in the Lockwood kit is fire sleeved.
 
Sensor & orfice

I believe the tiny orifice is to preserve the oil in case of a oil line failure. You have a little time to get on the ground before you loose all of your oil if your pressure goes to zero.:)

If I may add 2 points.
1. Lycoming and Conti have have an orifice in the oil pressure line at the engine for over 50 years from my A&P experience and it is to limit the loss of oil in the event of a line failure. Back when they used to use a stainless or copper line it wasn't unusual to find oil dripping from the cowling after landing when a line failed. It takes a long time to pump out all the oil from that orifice.

2. It's well know in the Rans (that's with an R) community that the sensors have a short life on the engine. I'm on the third in 970 hours on my 912 in an S-7S.

Bill
 
Don't recall

Tim

I still have the engine mounted sender. You mentioned a failure of a sensor. Was it a Honeywell or one of the older types that looks like a small can? Intuitively the Honeywell seems to have a smaller moment arm and should be less susceptible.

Rich

Sorry I don't recall. As I said this was an automotive application (fire engines), likely they were Cole Hersy or Stewart Warrner. And the failure mode being discussed here is different, these were breaking off, usually only after extended pump ops.
Tim
 
Sensor

Sorry I don't recall. As I said this was an automotive application (fire engines), likely they were Cole Hersy or Stewart Warrner. And the failure mode being discussed here is different, these were breaking off, usually only after extended pump ops.
Tim

All my failures have been with the earlier VDO type sensors, don't have any experience with the Honneywells.
 
Oil Pressure Sensor

"For those who had sensor failures what was the indication: zero pressure? Fluctuations? Oil leak?"

I was flying along with my 20 hour RV12, on my way to the paint shop and really into checking out displays with the Dynon ADS-B I had just installed. Received a warning over the headphones - "oil pressure low" or words to that effect. Went over to the Skyview engine screen and oil pressure was in the 17 - 20 pounds range. I backed off power, oil pressure went back up. Put power back in, oil pressure OK for a minute or so, then back to the teens.

Nearest airport was "on the way" so I continued. Oil pressure reading varied from normal to almost zero for a few minutes with more and more time near zero. Everything else normal with engine. I decided it was just the sensor and continued to destination. Eventually Skyview displayed a red X instead of the oil pressure reading.

I never did dig through the menu enough to shut off the oral warning. I did find that the RV12 audio overrides the Skyview warning with regular radio reception. So I was able to get some "peace" by tuning an ATIS that was close enough to hear.

There happened to be a Rotax dealer at the airport with the paint shop. I am having them replace the sender with the new sender Rotax is using in place of the Honeywell. Hope to pick up the plane with new paint and oil pressure sensor next week.
 
"For those who had sensor failures what was the indication: zero pressure? Fluctuations? Oil leak?"

I was flying along with my 20 hour RV12, on my way to the paint shop and really into checking out displays with the Dynon ADS-B I had just installed. Received a warning over the headphones - "oil pressure low" or words to that effect. Went over to the Skyview engine screen and oil pressure was in the 17 - 20 pounds range. I backed off power, oil pressure went back up. Put power back in, oil pressure OK for a minute or so, then back to the teens.

These same symptoms have been caused by a connection that becomes intermittent (often at the spade connectors in the harness) Troubleshooting for a possible wiring problem should always come before just replacing the sensor.
 
Sensor

Good point Scott. If I had the plane at home I would be trying that. The Rotax dealer said he expects it is the sensor. He said he has a test for it.
 
Oil pressure sensor failure

To add our experience of failed sensors, our first engine mounted Honeywell sensor failed after 29 hours and the second after 19 hours. We mounted the our third sensor remotely and this has clocked up around 80 hours and hopefully still going strong. Failure mode was zero pressure indication.

Alan
G-CGVD
 
A couple of thoughts:

- Is the fluctuation seen with the engine mounted sensors correct? That is, does the ACTUAL oil pressure vary as indicated?

- Do you "bleed" the oil line to the remote sensor location? If not, it is unlikely the line ever fills with oil - and air is a compressible fluid! If this is the case, it is possible that the fluctuations are damped out by the air in the oil line. If the line was bled to contain only oil (an in-compressible fluid) it is possible that the fluctuations would re-appear!
 
Failure mode

On all 3 failures the pressure indication went to zero.

All wiring connections were fine and the Pulsar was very smooth running. The prop was dynamically balanced and carbs were synchronized.

Gary
 
On all 3 failures the pressure indication went to zero.

All wiring connections were fine and the Pulsar was very smooth running. The prop was dynamically balanced and carbs were synchronized.

Gary

But an older engine with the VDO (metal can) type sensors. Correct?

All of the engines shipped to RV-12 builders have a newer (and now there is a newer than that) sensor.
 
PulsarXP

Yes you are correct, an older engine with the VDO style type sensor (both with the ring and without). My new engine for the Highlander came with a Honeywell sensor. From what I have read on numerous websites and blogs the Honeywell doesn't fare much better. Based on my previous experience I plan on remote mounting a VDO senor.

I am one of those builders that follow the plans and makes very few if any modifications. This is one that was made because the failure mode was unacceptable. I have heard others have never had a problem with the way it comes from Rotax.

Gary
 
Thanks for the replies. My original Honeywell has 80 hours with no problems yet. Now at least I know the common symptoms.
 
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