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HRII Fuel Pump Vent Clearance

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viperpilot

Joined: 28 Aug 2012
Posts: 11
Location: Peachtree City, GA

Posted: Sat Dec 08, 2012 2:20 pm Post subject: HRII Fuel Pump Vent Clearance

I am finally returning my ship to flying status, having been aground for upgrades and fixes following a prop strike nearly a year ago.  Mounting the IO-540 with new elastic mounts has changed the clearance at the back of the engine a bit.  The engine-mounted fuel pump drain is uncomfortably close to the firewall.  The firewall has been dimpled inward a bit to increase clearance during the previous engine installation, but additional dimpling does not appear to be available due to the proximity of a vertical structural member on the cockpit side of the firewall.



1.  Does anyone know of a method to increase clearance between the firewall and the fuel pump drain? 

2.  I have seen a few drain elbows of other aircraft that look to be smaller (or at least project aft less than the AN832-type fitting).  Are these available or are they custom made from an AN832-4?

3.  Vans notes that the threads on the Lycoming fuel pump are "special" and that NPT threads will not work--does that note apply to the vent drain?

4.  I assume that the vent drain only comes into play if there is a rupture in the fuel pump diaphram.  In that case, one is looking for fuel or oil coming from the vent drain as a major clue that the fuel pump is about to fail.  Is that an accurate statement?



Any assistance or comment would be greatly appreciated.



Thanks,

Randy Sage

Peachtree City, GA

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stuart(at)stuarthutchison
Guest

Posted: Sat Dec 08, 2012 3:27 pm Post subject: HRII Fuel Pump Vent Clearance

G'day Randy,



The vent thread is tapered and I'm pretty sure it's NPT.  The other fittings

are straight thread, sealed by O-ring.



I used a lathe, but the link  shows one option.  I ground the JB Weld flat

of course.



http://www.mykitlog.com/users/display_log.php?user=RockFLY&project=797&categ

ory=5584&log=131278&row=53



As you say, this should only vent fuel if the diaphragm is failing ... the

intent is to stop fuel entering the crankcase through the hole where the

actuator arm penetrates (top side of the diaphragm).



Kind regards, Stu



F1 Rocket    VH-FLY       http://www.mykitlog.com/RockFLY

www.teamrocketaircraft.com



--

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hr2pilot(at)aol.com
Guest

Posted: Sat Dec 08, 2012 3:29 pm Post subject: HRII Fuel Pump Vent Clearance

Do away with the fitting



Sent from my iPhone



On Dec 8, 2012, at 2:20 PM, "viperpilot" <nsage86(at)comcast.net> wrote:



 	  Quote: 	
		   

 

 I am finally returning my ship to flying status, having been aground for upgrades and fixes following a prop strike nearly a year ago.  Mounting the IO-540 with new elastic mounts has changed the clearance at the back of the engine a bit.  The engine-mounted fuel pump drain is uncomfortably close to the firewall.  The firewall has been dimpled inward a bit to increase clearance during the previous engine installation, but additional dimpling does not appear to be available due to the proximity of a vertical structural member on the cockpit side of the firewall.

 

 1.  Does anyone know of a method to increase clearance between the firewall and the fuel pump drain? 

 2.  I have seen a few drain elbows of other aircraft that look to be smaller (or at least project aft less than the AN832-type fitting).  Are these available or are they custom made from an AN832-4?

 3.  Vans notes that the threads on the Lycoming fuel pump are "special" and that NPT threads will not work--does that note apply to the vent drain?

 4.  I assume that the vent drain only comes into play if there is a rupture in the fuel pump diaphram.  In that case, one is looking for fuel or oil coming from the vent drain as a major clue that the fuel pump is about to fail.  Is that an accurate statement?

 

 Any assistance or comment would be greatly appreciated.

 

 Thanks,

 Randy Sage

 Peachtree City, GA

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=390071#390071

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viperpilot

Joined: 28 Aug 2012
Posts: 11
Location: Peachtree City, GA

Posted: Sat Dec 08, 2012 4:08 pm Post subject: Re: HRII Fuel Pump Vent Clearance

Thanks guys!  Stuart's solution is certainly the most elegant, but simply removing the fitting would seem to work also, as there should be no fuel coming out of the port if all is well inside the fuel pump.  Seems like the only reason to have the drain line is to make it easier to ID the problem and I am sure the FAA required it for certification.



Thanks,

Randy

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denis.walsh(at)comcast.ne
Guest

Posted: Sun Dec 09, 2012 7:42 am Post subject: HRII Fuel Pump Vent Clearance

Hey Randy



I am not a viper pilot but I play one in my dreams frequently.  I could say the same about rockets.  I can dream anyway.



In the dim reaches of my long term memory, I believe this is a long standing problem.  The RV 4 has a clearance problem which sounds like yours to me.  If so, Van's has a $9.50 solution. It is: Part Number = F OVERFLOW PLUG 1/8"

 Here is a link to the catalog:



http://vansaircraft.com/cgi-bin/store.cgi?ident=1355067275-394-210&browse=engines&product=overflow-fitting

Hope this helps.



Denis

On 8Dec, 2012, at 5:08 , "viperpilot" <nsage86(at)comcast.net> wrote:



 	  Quote: 	
		   

 

 Thanks guys!  Stuart's solution is certainly the most elegant, but simply removing the fitting would seem to work also, as there should be no fuel coming out of the port if all is well inside the fuel pump.  Seems like the only reason to have the drain line is to make it easier to ID the problem and I am sure the FAA required it for certification.

 

 Thanks,

 Randy

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=390080#390080

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ctlimited(at)hotmail.com
Guest

Posted: Sun Dec 09, 2012 8:12 am Post subject: HRII Fuel Pump Vent Clearance

Denis,That was great, I will be laughing all day about that one, Thanks.

 	  Quote: 	
		   Subject: Re: Re: HRII Fuel Pump Vent Clearance

 From: denis.walsh(at)comcast.net

 Date: Sun, 9 Dec 2012 08:42:21 -0700

 To: rocket-list(at)matronics.com

 

 --> Rocket-List message posted by: Denis Walsh <denis.walsh(at)comcast.net>

 

 Hey Randy

 

 I am not a viper pilot but I play one in my dreams frequently.  I could say the same about rockets.  I can dream anyway.

 

 In the dim reaches of my long term memory, I believe this is a long standing problem.  The RV 4 has a clearance problem which sounds like yours to me.  If so, Van's has a $9.50 solution. It is: Part Number = F OVERFLOW PLUG 1/8"

 

 

  Here is a link to the catalog:

 

 http://vansaircraft.com/cgi-bin/store.cgi?ident=1355067275-394-210&browse=engines&product=overflow-fitting

 

 

 Hope this helps.

 

 Denis

 On 8Dec, 2012, at 5:08 , "viperpilot" <nsage86(at)comcast.net> wrote:

 

 > --> Rocket-List message posted by: "viperpilot" <nsage86(at)comcast.net>

 > 

 > Thanks guys!  Stuart's solution is certainly the most elegant, but simply removing the fitting would seem to work also, as there should be no fuel coming out of the port if all is well inside the fuel pump.  Seems like the only reason to have the drain line is to make it easier to ID the problem and I am sure the FAA required it for certification.

 > 

 > Thanks,

 > Randy

 > 

 > 

 > 

 > 

 > Read this topic online here:

 > 

 > http://forums.matronics.com/viewtopic.php?p=390080#390080

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 > 

 

 

 <b=

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viperpilot

Joined: 28 Aug 2012
Posts: 11
Location: Peachtree City, GA

Posted: Sun Dec 09, 2012 8:24 am Post subject: Re: HRII Fuel Pump Vent Clearance

Denis!  My Man!!



Thanks,

Randy

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