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Oil filter and fuel flow

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ajroseca(at)nf.sympatico.
Guest

Posted: Tue May 21, 2013 4:50 am Post subject: Oil filter and fuel flow

My ch701 has a 912uls engine.,,,,,,, can anyone recommend a new oil

 filter replacement number other then the rotax unit ...which will  work

 ok. I have seen a number of these filters that look same as the rotax

 unit..is there a difference.

 Also My 701 is using gas on the passenger side tank ..but not much on

 the pilot side until the right tank is low..how can I get the two  tanks

 to drain equally..Both tanks are vented properly and I can find nothing  wrong with

 this zenair setup..any suggestions would be appreciated.

 Have a nice day and lots of happy flying

 Alvin Rose

 CH-701 ZENAIR , CIHLI

   [quote][b]

dougsnash

Joined: 14 Apr 2008
Posts: 281

Posted: Tue May 21, 2013 6:04 am Post subject: Oil filter and fuel flow

Alvin, there are several similar oils filters to what comes from Rotax but Rotax uses a custom bypass spring pressure in their filters.  According to Lockwood, an automotive filter would pop open the bypass valve at the pressures commonly run in the filter and thus not effectively filter your oil.  Unless you are having a difficult time sourcing the OEM Rotax filter, I would stick with what is recommended.



As for differential fuel flow, I have a similar issue with my fuel system except it is my left tank which flows more at the beginning.  I have 3/8" hard piped fuel lines and one common shut-off valve in front of the seat.  Generally, my fuel levels balance by the the 50% level.  One thing I have noticed and am wondering if it makes a difference is that the vent holes in my fuel caps are 90 degrees to each  other. When the tanks were welded by Zenith the caps were misaligned.  Also, the location of the "T" which joins the two tank feeds together might have an effect on the balancing of the fuel flow.  My lines come together at the gascolator which is mounted under the pilot seat.  I'm not too worried about the uneven fuel flow as I have found the fuel levels generally even out in the bottom half of the tank.  I drained my tanks this weekend to change to a different style sending unit and the left tank was dry only slightly before the right tank.  Fuel continued to flow normally through my gascolator drain valve even with the one tank drained.



I have heard of 701 owners placing valves in the lines coming from the fuel tanks to address the uneven fuel flow issue.  While this would be effective in balancing the fuel usage, I personally feel it is one (or two) more component(s) which could either fail or be a source for  pilot error.  Given that my fuel levels balance out as the fuel level gets lower, I am not planning on adding any more complexity to my fuel system.  If you find the fuel levels are not equalizing soon enough for your comfort, you might want to consider placing valves in each of the feed lines from the tanks.



I hope I have adequately answered your questions.



Doug M

CH-701 mostly from scratch

NW Ontario, Canada





        From: AJR <ajroseca(at)nf.sympatico.ca>

 To: zenith701801-list(at)matronics.com 

 Sent: Tuesday, May 21, 2013  7:50:09 AM

 Subject: Zenith701801-List: Oil filter and fuel flow

  

 

    My ch701 has a 912uls engine.,,,,,,, can anyone recommend a new oil

 filter replacement number other then the rotax unit ...which will  work

 ok. I have seen a number of these filters that look same as the rotax

 unit..is there a difference.

 Also My 701 is using gas on the passenger side tank ..but not much on

 the pilot side until the right tank is low..how can I get the two  tanks

 to drain equally..Both tanks are vented properly and I can find nothing  wrong with

 this zenair setup..any suggestions would be appreciated.

 Have a nice day and lots of happy flying

 Alvin Rose

 CH-701 ZENAIR , CIHLI

    	  Quote: 	
		  http://www.matronics.com/Navigator?Zenith701801-Listw" target="_blank" href="http://www.matronics.com/contribution">http://=======================


	






 

 

  

 [quote][b]

john.marzulli(at)gmail.co
Guest

Posted: Tue May 21, 2013 6:07 am Post subject: Oil filter and fuel flow

Any reason why you want to use a different oil filter?



As for fuel flow, many have reported similar issues of uneven fuel drain. I encountered this as well. There are several things you could be experiencing such as venting issues, or cross-flow due to crabbing, ect.

 



My first suggestion is to double check the additional venting hole in the fuel caps. Make sure the are large enough and in the proper location.

My second suggestion is to switch your fuel selector. My plane has an Andair L\R\B\Off selector. It is mounted with a custom bracket on the pilot side in a vertical positon between the lower edge of the panel and the frame tube that acts as a door sill. My plane has two gascolators\sumps (one fore each wing) instead of the standard one. I also have a fuel filter per wing visible in the cockpit.

 



This gives me control over fuel management and prevents any cross-feeding while on the ground.

Good luck!



 John Marzulli



http://MarzulliPhoto.net/

http://701Builder.blogspot.com/

 



On Tue, May 21, 2013 at 5:50 AM, AJR <ajroseca(at)nf.sympatico.ca (ajroseca(at)nf.sympatico.ca)> wrote:

[quote]     My ch701 has a 912uls engine.,,,,,,, can anyone recommend a new oil

 filter replacement number other then the rotax unit ...which will  work

 ok. I have seen a number of these filters that look same as the rotax

 unit..is there a difference.

 Also My 701 is using gas on the passenger side tank ..but not much on

 the pilot side until the right tank is low..how can I get the two  tanks

 to drain equally..Both tanks are vented properly and I can find nothing  wrong with

 this zenair setup..any suggestions would be appreciated.

 Have a nice day and lots of happy flying

 Alvin Rose

 CH-701 ZENAIR , CIHLI

    	  Quote: 	
		  



ist" target="_blank">http://www.matronics.com/Navigator?Zenith701801-List

tp://forums.matronics.com

_blank">http://www.matronics.com/contribution



	


[b]

ronlee

Joined: 25 Dec 2006
Posts: 141

Posted: Tue May 21, 2013 11:06 am Post subject: Re: Oil filter and fuel flow

I think I have figured out the uneven fuel flow by accident on my 701 and probably all of them. I left the fuel cap off one very short flight and noticed one fuel tank filling and the other emptying while in flight. When I thought about it, I came to the conclusion that it is the uneven air pressure in each tank that causes this.The problem is one that has puzzled me and others on the 701. There is no pressure equalizing line between the tanks so the same pressure will never be the same in each tank, thus feeding one faster the the other.. It was amazing how fast the fuel from two 1/2 tanks of fuel ended up in one tank. I have been trying to figure out how to put a pressure equalizer tube between the two tanks so only one has to be vented which would cause the pressure in each tank to be equal. Some high wing aircraft that drain from both tanks at the same time do it that way.

_________________
Ron Lee
Tucson, Arizona

n801bh(at)netzero.com
Guest

Posted: Tue May 21, 2013 2:55 pm Post subject: Oil filter and fuel flow

I run a balance line to all of my tanks  that interconnect them.... Mine still draws more fuel from one side then the other.... My guess is the prop blast hits the top of one wing and the bottom of the other and that imbalance creates uneven flows 

  

do not archive

Ben Haas

N801BH

www.haaspowerair.com



--------

ronlee

Joined: 25 Dec 2006
Posts: 141

Posted: Wed May 22, 2013 6:27 am Post subject: Re: Oil filter and fuel flow

My tanks have a balance line which is where they "T" together before the valve. If the plane is parked level the tanks will equal out to seek the level of the other one. What I was speaking of is an air line between the tanks to equalize the air pressure above the fuel while in flight, as that is what varies and causes uneaqual fuel flow in my opinion.

_________________
Ron Lee
Tucson, Arizona

n801bh(at)netzero.com
Guest

Posted: Wed May 22, 2013 6:46 am Post subject: Oil filter and fuel flow

My 801 has dedicated fuel lines from each wing to  independant fuel cut off valves.... I also have the vent lines connected to the fittings welded into the tops of all tanks and that line is connected to both wings..... I ALSO have seperate vent lines on each tank protruding below the wing in the high pressure area....... Even with all my vents, my 801 will drain from one side more then the other....  

Ps, after my first flight and the resulting siphoning of the fuel through the Zenith supplied vented caps, That causes the 100LL fuel to permanently stain my 300 dollar a gallon Imron paint.. Yeah... That really pissed me off too...... So I epoxyed those vent holes up in those caps to prevent any future staining.... After 9 years, 500 hours and maybe 4000 gallons of fuel run through my plane I have not had ONE issue with fuel supply..... I mention this for reference for others... 

do not archive

Ben Haas

N801BH

www.haaspowerair.com



--------

d.shrader

Joined: 21 Nov 2008
Posts: 38

Posted: Tue May 28, 2013 11:01 am Post subject: Re: Oil filter and fuel flow

Ben,



How did you get the balance line from one wing to the other without putting a dip in the line through the cabin.  I considered a balance line but it would be rendered useless if fuel was trapped in the low spot. 



Dave

RichardF

Joined: 27 Nov 2012
Posts: 5
Location: Southampton UK

Posted: Wed May 29, 2013 11:31 am Post subject: Re: Oil filter and fuel flow

Just a theory of mine.  Our 701 also has the fuel tank contents disparity and I think that this is due to the fuller tank, left one in our case, having the engine (Rotax 912) fuel return pipe going to it.  At this stage am unsure how much fuel is actually returned to the tank per hour of flight.  Just a thought.

Richard

d.shrader

Joined: 21 Nov 2008
Posts: 38

Posted: Wed May 29, 2013 4:46 pm Post subject: Re: Oil filter and fuel flow

Richard,

I flew a tecnam Super echo set up in the same way (fuel return to r/h main) and it behaved the same, it was so bad in fact that if you flew on both with the mains toped off the R main would overboard fuel out the vent pipe (small amount).  My question is why run the return line back to the tank?  If I remember correctly we just returned it to the supply line.



Dave

sonar1@cox.net

Joined: 02 Oct 2007
Posts: 55
Location: Santa Barbara, Ca

Posted: Thu May 30, 2013 7:47 am Post subject: Re: Oil filter and fuel flow

On the uneven fuel flow. I have been flying my 701 for 8 years. I had uneven fuel flow like everyone else.

I built a mockup with transparent tanks and 1/4 inch lines, and just sitting on my porch with no airflow pressures or forward facing vents or balance lines, I could see the same uneven flow  tendencies. Little bubbles were forming and stopping the flow (but not sure that that is the problem with 3/8 lines). I put a small tv camera inside my full gas tank and found lots of bubbles in the finger screen. Don't know how they got there.

 Concluded that the only way to have control over the fuel flow was to have separate valves - one for each tank, so I now run the fuel lines under the seat to two valves on the floor, and then to the Aircraft Spruce gascolator forward of the firewall. I have total control. No more worry about an inadequate design.

 912ul, no return line,  original internally vented caps.

  I did have my green plastic alcohol resistant (from Spruce) fuel line disintegrate right at the wing root and spill ten gallons of fuel down the cabin side, through the baggage compartment and out the bottom  onto the hangar floor . Changed to automotive rubber lines.

Fred Sanford  N9701

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