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Thanks for the input.
I have tried a different filter (both were B&N ) and I have used a mechanical sensor. However, it was placed where the electronic sensor is (as well as after the PSRU and out the top of the engine going to the turbo), not right
after where the oil leaves the engine. The usual sensor location in mine is right after the primary cooler. i have been checking the hoses, but have not completed this task but so far have been clear of obstructions. If I tear down the engine ,
I will likely have the hoses pressure tested by a friend in the business...I have seen the flap made by the Earls fittings. TIA
From: Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of Ed Anderson [eanderson@carolina.rr.com]
Sent: Wednesday, September 29, 2010 1:28 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Oil Pressure Loss
Chris,
Not certain where you have your oil pressure sensor, but on my old 13B it is after the filter and oil cooler - actually its on the aluminum block. The point is my pressure sensor is after all of the components in the cooling system.
I suspect your's is as well.
So assuming your oil pump is OK here is what we have remaining.
1. There is an "O" ring between the aluminum front cover and the iron housing (unless it has been removed and some substitute is there). If this gets pushed out the oil pressure tyically drop down to around 20-30 psi at max rpm). It
will generally permit some oil to flow.
2. If the filter becomes clogged then most oil filters have a high pressure by-pass which permits oil to flow even thought it will not be filtered (better some dirty oil rather than a fried main bearing)
3. Hoses that have "Earls" type aluminum fittings have been know to shave a rubber flap when being installed and could have gotten into a position to block flow.
You keep remarking that the oil flows to the filter but not past it - even when you filled the filter with oil. That would cause me to try replacing that filter with a different one. Oil filters have been know to have their internals
collapse and block flow. Unlikely - but you are looking for any possibility to preclude tearing into the engine so don't over look this one.
As several have suggested you really need to have a mechanical pressure gauge to see what your oil pressure is. You may have to cook up some An fittings to block the oil flow before it gets to the filter and insert a pressure fitting
and gauge at that point. As long as your engine does not start have no oil flowing for few revolutions should not hurt your bearings - take a reading - if pressure doesn't come up with the flow blocked by your measuring device then you have an internal problem.
Could be the "O" ring, could be the keys in the pump (I had that happen to me once - flew for 10 hours before the clamping nut on the oil shaft let go and pressure dropped during taxi - fortunately), could be the pump, could be your oil pick up.
Good luck
Ed
Sent: Wednesday, September 29, 2010 1:43 PM
Subject: [FlyRotary] Re: Oil Pressure Loss
Sorry, I have had some major issues with notebook computer I usually use at home. Most recently with the mouse freezing, so, I had to use three post that should have been one.
I have NOT had the engine apart. It has about 45 hours on it since I performed the latest rebuild using mostly new parts (rotor & end housings, rebuild kit...old rotors and e-shaft). It had been running damn good, good enough that I thought I was really
close to the DAR sign off and first flight attempt. The RPM indicator drop was a residual issue with the EM2 I was working on trying to tie up loose ends.
As I mentioned, I would have not had noticed an issue just listening and watching the engine, but while I was trying (unsuccessfully) to solve my RPM drop reading problem I noted the OP flashing and the low pressure reading.
I am getting some oil coming out of the front of the engine and into the remote oil filter which is located between the engine outlet and the coolers, however, I have apparently not had enough pressure to move oil out of the filter. I replaced
the filter and the same thing occurred . Perhaps I have not cranked the engine long enough to move it through the filter as it was getting dark and I had not yet moved the spark plugs and was concerned about damaging the internals and PSRU .
Even though I am getting flow out of the engine when cranking with the plugs installed, I do not know how much flow it is....it is steady, but does not seem all that strong, but of course, the engine is only cranking and not running. Also, since I had
no oil flow, I was concerned about cranking it without oil getting to the engine and PSRU . I hope to get out to the hangar later today and continue my checks with the plugs removed. I am not too hopeful though, it seems as if it must
be an internal issue, especially since the mechanical gauges I hooked up also showed low/no pressure.
I agree, I do not wish to tear down the engine, as I have a lot installed on top of it, plus the PITA of opening the dang thing up. However, I have gotten pretty good and uninstalling and reinstalling...(of course, apparently not good enough to
not have a problem). The process has gotten much faster as I have become more methodical.
Dave mentioned some of the issues we know about with keys and retaining clips. While something like that could certainly be the problem, I am certain I addressed these very items, even though possibly not well enough. If you would have asked,
I would have thought it was good, but now the evidence will tell.
I have removed most the hoses to check for obstructions and have yet to find any. Again, the oil is coming out of the front of the engine in a stream but low pressure with simple starter cranking, but as of yet has not made it past the filter, which is
the first "event" in the chain.
Do we know of a way to determine how much oil should be flowing with simple cranking...such as "x" amount into a jar in "y" time cranking? Yeah, grasping at straws...but I am trying to get use to the idea of pulling the engine.
Heavy sigh.
Thanks,
Chris
From: Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of Bill Brwhadburry [bbradburry@bellsouth.net]
Sent: Wednesday, September 29, 2010 12:00 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Oil Pressure Loss
Chris,
Did you just have your engine apart? If so, did you have oil pressure after that? Oil from the pump comes out of the lower front
housing and goes to the cooler. Did you check to see if oil is coming from the first opening after the pump? If it is not, the problem is inside the engine, if oil is coming from the pump, the problem is outside the engine. Cooler, filter, hose, etc, don’t
tear it down unless you have to. If you didn’t use a mandrel when you made up your hoses, you could have a sliver of the inside of the hose blocking the oil flow.
Bill B
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
On Behalf Of Chris Barber
Sent: Tuesday, September 28, 2010 11:26 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Oil Pressure Loss
Oh, and maybe this is too obvious, but when I drop the pan, what should I be looking for. Yeah, large metal shards I would figure
out, but if it is not that obvious, where do I need to focus. The pressure gage?? The pump?? Something else??
From:
Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of Chris Barber [cbarber@texasattorney.net]
Sent: Tuesday, September 28, 2010 10:11 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Oil Pressure Loss
Geeesh...the mouse froze again.
To continue, I got a moderate, steady stream of oil coming from the remote filter mount. So, I had some flow. I then went to the
end of the hoses where it re-enters the engine after flowing through the two oil coolers. Well, here there was no joy. No oil coming out. I did refill the filter before I reinstalled it and cranked the engine for quite a while to no avail. Next, I unhooked
a few of the other hose connections past the filter and still no flow when cranking. Finally, I checked all the way back to the filter outlet and no oil would come out. I changed to a different filter and still no flow from out of the filter. So, I have
some flow....not a lot into the filter buy none out.
I HATE the idea of dropping the pan (will be a real pain) to check the oil pump and pressure gage, but I am not quite sure as what
else to check at this point. When I return tomorrow, I will remove the plugs to take some of the stress off the starter and see if I get flow out of the filter. I am also concerned now that I have been cranking the system long enough that some important
parts are not running with a lot of needed oil, such as the PSRU etc.
If I would have just happened to look at the OP gauge, I would have never known there was a problem as the engine "sounded" strong
and smooth and continued to do so when I started it to test my pressure after discovering the problems.
Hopefully this will be a bit more directly answered by the engine guru types on the list since it is not specific to Tracy's electronics.
Please, what else should I check, I am about at the end of my testing skill set. Also, what say ye as to what the problem "sounds"
like????
From:
Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of Chris Barber [cbarber@texasattorney.net]
Sent: Tuesday, September 28, 2010 9:59 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Oil Pressure Loss
Aggg. I need a new computer. The mouse froze and the message sent prematurly.
Anyway, I rechecked the wires to the EM2 and at the sensor again and all checked fine. Again, I started the engine, but was shut
down as soon as I still saw no pressure.
Next, I hooked up two separate mechanical pressure gages in three different locations in the oil system, started the engine three
times very briefly. Each time the engin started and seemed to run fine for the VERY short time I allowed it to run. No pressure reading on two of the test points, and about 6psi on the reading from the turbor engine outlet to the turbo.
Ok, I unscrewed the oil filter, which is located remotely just as the oil comes out of the front (by the pully's oposite the prop)
of the engine. I hooked up a remote start switch, climbed under the engine and cranked the engie.....I got a moderate, steady flow of oil
From:
Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of Chris Barber [cbarber@texasattorney.net]
Sent: Tuesday, September 28, 2010 9:42 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Oil Pressure Loss
In the never ending tradition of two step forward and three steps back, I was working on my RPM drop out at 6000 rmp (messed with seveal
resistors to no avail). As I was sitting on the ramp at idle for a few minutes, focusing on the RPM's I glanced over at the Oil Pressure and noted it was flashing as an alert and was showing almost NO oil pressure (4 or 5 psi). I instantly shut down the
engine.
The engine appeared to be running fine before I shut it down. I checked the wire to the back of the engine monitor and all was
fine. I also checked the continutiy of the wire to the sensor and it was good. I started the engine again and it started fine and seem to run fine, however, the OP did not kick in so I shut it down again
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