paul.r.kuntz(at)gmail.com Guest
|
Posted: Tue Dec 28, 2010 5:37 pm Post subject: Rotax 912 oil system prime and purge |
|
|
I am completing installation of a Rotax 912UL in a Pipistrel Sinus. The installation includes an oil temperature thermostat. I acquired an oil priming kit from California Power Systems and am following the instructions in the kit, as well as the video on the Rotax Owners web site. See the links below to a couple of photos of my installation.
Oil thermostat: http://webhosting.web.com/imagelib/sitebuilder/misc/show_image.html?linkedwidth=actual&linkpath=http://www.pipistrelbuilders.com/sitebuildercontent/sitebuilderpictures/oil_thermostat_12.JPG&target=tlx_pic2orp
Oil cooler: http://webhosting.web.com/imagelib/sitebuilder/misc/show_image.html?linkedwidth=actual&linkpath=http://www.pipistrelbuilders.com/sitebuildercontent/sitebuilderpictures/Baffle_seal_1.JPG&target=tlx_picm5rc
I have a few questions:
I have applied air pressure to the oil tank and turned the prop through until I get oil pressure and oil is coming out of the oil return line. The oil comes out in a slow trickle. Should it be a flow with some real volume? That is, should it gush out, or is a small trickle enough?
I don't have my engine instrumentation installed yet, so I am measuring the resistance of the VDO sender to determine oil pressure. I get 8.1 ohms with no pressure in the system, which corresponds reasonably well with some calibration data that appears on this forum awhile back. I get about 45 ohms while turning the prop through, which would indicate something above 30 psi at the sender, so I seem to be getting good oil pressure.
Various sources that describe the purge procedure talk about using "appropriate measures" to ensure that the oil circuit through the oil cooler is filled, because the oil cooler is bypassed by the thermostat when the oil is cold. I'm doing the purge at normal room temperature, and the person I spoke with at CPS said that there will always be some oil passed through the oil cooler circuit, even when the thermostat is cool. After achieving the purge conditions described above, I tried pulling the oil hose off of the outlet fitting on the oil cooler, expecting to find both the cooler and the hose full of oil. What I found is evidence that oil is flowing through there, by way of some oil dripping out of the hose, but they certainly weren't full of oil.
So, I used a heat gun to warm up the thermostat until is was hot to the touch, then pulled the prop through for a bunch of revolutions. This appears to draw some more oil out of the oil tank, as evidenced by a drop in the oil level, and some more oil came out of the return line -- perhaps a half a cup or so during this step. Then I pulled the hose from the oil cooler again, with the same result as before -- some oil present, but the line is basically empty and full of air.
What should I be expecting? Are the cooler and the lines going to fill with oil and remain full? Seems like they should. The purging instructions and the warnings about engine damage all talk about getting rid of all air in the system. Otherwise, if I ran the engine right now, a whole bunch of air is going to hit the oil pump, which will be a bad thing.
I realize that by pulling the oil line from the cooler I am breaking the system seal and introducing an air pocket, which will have to be purged out, but until I checked that hose, it appeared to me that I had achieved the objectives of the purge. That is, I had 30 psi of oil pressure and I had oil coming out of the return line.
Advice?
Regards,
Paul Kuntz
[quote][b]
| - The Matronics RotaxEngines-List Email Forum - | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?RotaxEngines-List |
|
|
|