Oil Pressure

[Roger Lee]

Posted by 207WF from another forum:

LocationHermosa Beach, CA

 

 

Someone said that in the rotax schools they talk about pressures for long-lived engines and that lower pressures can be good. I wonder because some show 55-65 psi, while others (like me) showed 32. With the cone, cap and spring mod. we put in one shim which took the pressures up to 34psi, and it is steadier. I could put in more shims. Should I ? WF

[Roger Lee]

Hi Guys,

 

Putting shims in without taking a separate mechanical pressure is a bad idea. First Rotax likes oil quantity over high pressure. This is one of the things they talk about in their schools. Normal pressure seems to be for most folks between 32-60 psi. Yes it could be a tad higher and be within normal range. Rotax states 22-73 psi is within limits. The problem here is that the oil pressure sender is usually lying to you if you are at the top or bottom end of the scale. I have seen people put shims in when they thought their oil pressure was in the 30's and then to find out later that the real pressure at the time was in the 50's. A shim will add approximately 7 psi. The new Rotax oil pressure regulator parts do seem to raise the pressure and make it more steady and that is what they were designed to do. It also helps cut down on the chatter between the old ball bearing and fluctuating pressure. So if you have a 32 psi pressure after you install the new parts, then before you add anything suspect the oil pressure sender being false until proven otherwise. I just replaced a wide swinging oil pressure sender 2 days ago. It was setting off the high oil pressure alarm on a Dynon. After it was replaced the oil pressure settled down to approximately 58 psi.

[N89WD]

RL, just had Bob do my annual and we relocated the oil pressure sending unit. My oil pressure was always running at 30, when moved to the firewall it now is at 42. I had a bad or weak sending unit. Having it off the engine is much better, with less vibration and will live longer. C-ya

[Roger Lee]

Hi N89WD,

 

Remote mounting the oil pressure sender does help with vibration and longevity. It is an approved Rotax mod. maybe more people will follow. Have you done the 2000 Hr. TBO oil pressure parts exchange yet? That may also help.

[N89WD]

Hi N89WD,

 

Remote mounting the oil pressure sender does help with vibration and longevity. It is an approved Rotax mod. maybe more people will follow. Have you done the 2000 Hr. TBO oil pressure parts exchange yet? That may also help.

 

 

Negitive...Bob says my engine block does not qualify for the 2000 hr TBO. I'm happy with the sender relocate outcome.

[Roger Lee]

Hi N89WD,

 

Even if you don't qualify for the 2000 TBO Rotax still recommends that all 912 users install the newer parts. The new parts do seem to make a difference for a number of people. The new cone is shaped different and has a hole in it and the new cap screw has a taller shoulder and all this helps keep the people with some fluctuation down and seems to increase the pressure for some, but it also helps some of the chatter that goes on at the ball bearing for some. The taller cap screw is a harder metal and with its tall shoulder helps hold the spring straight and doesn't let it bend over.

[Tip]

Roger,

Do you have the part number for the new cone?

[Roger Lee]

Hi Tip,

 

You should use all three new parts.

 

cap screw 841-983 about $32- $35

spring 838-122 about $8

regulator cone 857-230 about $30- $33

 

prices very slightly from dealer to dealer.

[Jeremy MacGregor]

Hey Roger,

First of all the spec is 29-73 PSI for Normal operation but they say you can go as low as 12 momentarily below 3500rpm. Im usually having about the same symptoms as you anywhere from 45-75 which the factory had told me is perfectly normal during start up but once I hit about +150 F my pressure seems to drop down and anytime Im over about 4000rpm in the air Im from about 31-38psi every 30 seconds or so it flashes 45 or 52 or something like that. With a bearingless camshaft Im certianly of the opinion that quantity over pressure is better as long as its in range. I still have my oil pressure sensor on my pump, which in my opinion is good and bad. Ive been debating weather or not to try the Honeywell sensor but considering the cost and that the fact that we've had a few warranty claims on them already Im not so sure its worth it.

[FlyRatz]

Hi CT-Friends,

 

recently I managed to mount the new Oil Pressure Sender from Rotax (Part No. 956413) at one of our two CTSW's. This sensor is a piezo type from Honeywell and does not have any movable items inside. So this sensor should last for a engines life and should not be a victim to the engines vibrations.

Both of our CTSW's have the new cone shaped oil-pressure-valve installed already.

 

The change of the sensor was done in 10 minutes. The installation of the new wire took me about 2 hrs. Fortunately the Dynon EMS 120 supports this sensor with the latest revision of the software (which I needed to install). In addition to the sensor, one needs a 200 Ohm resistor ( 1 Watt type) to adapt the sensor to the Dynon electrically.

 

Experience from the first engine run:

Indicated oil pressure seems much more reliable in comparison to the old sensor. With the old sensor, we saw oil pressure in the 30-40 PSI range and the readings have been very unstable. With the new sensor, the readings are in the 40-60 PSI range and they are stable like a rock.

 

Conclusion:

This upgrade makes very much sense to me.

 

Greetings

 

Markus

[Runtoeat]

Does anyone have the part number for the aftermarket VDO oil pressure sender which some are using to replace the factory sender? I see there's a thread from Waggles where the brass ring can be removed from the factory sender and installed on the aftermarket sender. I'm assuming that this aftermarket VDO sender can be obtained from places such as a NAPA parts store?

[Roger Lee]

Hi Dick,

 

Call Lockwood. They have it and it is $39.95.

VDO part #V360-004.

You can use a heat gun to remove the old ring, but you should not over heat the sender. The big question is why even bother, it doesn't seem to have any relation to how long a sender will last. I have replaced several with the ring and have not replaced a single one without the ring.

 

 

Tom is right I originally gave you the fuel pressure sender number. It is now corrected above.

[Tom Baker]

NAPA does not carry the correct part, however Jegs and Summit carry the part. It's a VDO V360-004 sender. Cost is about $25 from these two. I think Roger gave the fuel pressure sender number. Tom

[Runtoeat]

Tom and Roger, thanks for the good info.