---------------------------------------------------------- Engines-List Digest Archive --- Total Messages Posted Fri 03/16/07: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:41 AM - Re: Fuel pump tests (Hinde, Frank George (Corvallis)) 2. 07:51 AM - Re: Fuel pump tests (BELTEDAIR@aol.com) 3. 08:16 AM - Re: Fuel pump tests (Hinde, Frank George (Corvallis)) 4. 02:06 PM - Re: Fuel pump tests (n801bh@netzero.com) 5. 05:33 PM - Fuel pump tests (Gene Smith) ________________________________ Message 1 _____________________________________ Time: 07:41:05 AM PST US Subject: RE: Engines-List: Fuel pump tests From: "Hinde, Frank George (Corvallis)" But didn't you say you saw bubbles with the clear hoses? This implies the onset of fuel boiling on the suction side of the pump. I guess my concern is if you saw bubbles on the ground then these bubbles are likely to be larger at the conditions I described. In other words my concern is you might be getting a little close to a true vapour lock situation. Cheers Frank -----Original Message----- From: owner-engines-list-server@matronics.com [mailto:owner-engines-list-server@matronics.com] On Behalf Of Gilles Thesee Sent: Thursday, March 15, 2007 1:17 PM Subject: Re: Engines-List: Fuel pump tests --> Hinde, Frank George (Corvallis) a crit : > --> > > > Your right that is exactly what is happening. It also gets worse as > the temperature of the fuel increases, namely thru a hot engine driven > pump...I gets worse further with altitude and the harder you suck on > the fuel. When it gets really bad its called vapour lock and your > engine quits. It will also happen more with autofuel than with 100LL > due to the higher vapour pressure of the mogas. Low wing airplanes > (with wing tanks and no header tank are much more susceptable because > the engine driven pump is sucking uphill. > > This coindiently may happen at the worse possible time i.e a hot > Summer day at a high altitude airport where your fuel has been heat > soaked....You run full power, the engine gets real hot and Here come > the trees! > > So, what to do?....Mount a low pressure electric pump as close to the > outlet of tha tank as possible with no pressure drop on the inlet side > of the pump. > Frank, Thank you for responding. Actually we have wing tanks and our pumps are on the firewall, some inches higher than wing root level. To date we've reached FL 145 in winter on Avgas, and recently flew at FL 135 on Mogas without any problems. I also flew at 37C OAT (only up to 6000 ft). But you're right on the pumps in the wing roots in a perfect circuit. Best regards, Gilles http://contrails.free.fr ________________________________ Message 2 _____________________________________ Time: 07:51:58 AM PST US From: BELTEDAIR@aol.com Subject: Re: Engines-List: Fuel pump tests Dear List: I have just gotten in on the tail end of this problem, but we have been working with people to come to a solution. We found the fuel selector valve on low wing planes to be leaking air around the shaft but not leaking fuel. IF it were a high wing with a lot of head pressure fuel would seep out. But on low wing planes fuel does not seep out but air in. We built a manometer to prove the theory. We changed the .06 cent "O"ring around the shaft then put a drop of engine oil to make sure it did not pull in. We experienced engine roughness at high power settings returning to normal at lower power settings. If the aux fuel pump were turned on, it made the condition worse. In early 2006 we went back 5 years in the NTSB files and found 99 instances where the engine quit then would run when it was removed from the wreckage. Fuel injected engines are worse due to the high suction. It equates to putting a hole in a straw and trying to drink. This was found on the "Imperial" type valve. This valve was and is used in most GA and experimetal craft. Jess ************************************** AOL now offers free email to everyone. Find out more about what's free from AOL at http://www.aol.com. ________________________________ Message 3 _____________________________________ Time: 08:16:13 AM PST US Subject: RE: Engines-List: Fuel pump tests From: "Hinde, Frank George (Corvallis)" Excuse my sceptisism but it seems you are now relying on a 25cent O ring... and a single point of failure to boot. Personally i would rather redesign the system to be "hydraulically correct" i.e no sucking anywhere in the system as a fuel leak is a minor problem that has good warning qualities (stink). And air leak has almost no warning qualities until your engine stumbles or quits. Of course if you have big lines and very low pressure drop through the valve on the inlet side to the pump the problem is much reduced on a suck type system, but if you have electric pumps anyway then its worth putting them in the correct place if space permits. As you say, this has resulted in wreckage! Frank ________________________________ From: owner-engines-list-server@matronics.com [mailto:owner-engines-list-server@matronics.com] On Behalf Of BELTEDAIR@aol.com Sent: Friday, March 16, 2007 7:51 AM Subject: Re: Engines-List: Fuel pump tests Dear List: I have just gotten in on the tail end of this problem, but we have been working with people to come to a solution. We found the fuel selector valve on low wing planes to be leaking air around the shaft but not leaking fuel. IF it were a high wing with a lot of head pressure fuel would seep out. But on low wing planes fuel does not seep out but air in. We built a manometer to prove the theory. We changed the .06 cent "O"ring around the shaft then put a drop of engine oil to make sure it did not pull in. We experienced engine roughness at high power settings returning to normal at lower power settings. If the aux fuel pump were turned on, it made the condition worse. In early 2006 we went back 5 years in the NTSB files and found 99 instances where the engine quit then would run when it was removed from the wreckage. Fuel injected engines are worse due to the high suction. It equates to putting a hole in a straw and trying to drink. This was found on the "Imperial" type valve. This valve was and is used in most GA and experimetal craft. Jess ________________________________ AOL now offers free email to everyone. Find out more about what's free from AOL at AOL.com . ________________________________ Message 4 _____________________________________ Time: 02:06:58 PM PST US From: "n801bh@netzero.com" Subject: Re: Engines-List: Fuel pump tests Jess makes a good redrive unit and lives where is is" hot" in the summer , in fact it is in the 90's down there now. YUCK. Jess,I am assuming yo u are running mogas in your V-6 Chevy.If so have you ever had a vapor lo ck condition in the extreme heat of Las Vegas? I made a test of mogas o n my beast last year and it hiccuped at 13,000 and 45f degrees. That go t my attention but I safely made it back on the ground.I am not sure the fuel was the problem though because I made some other changes at the sa me time trying to get the oil cooler to shed more heat and probably elev ated the under cowl temp too much which heated up the fuel lines going t o the carb. Plane goes up to 17,999 msl perfectly on 100LL. I would like to hear stories from people on past experiences of runnig mogasand vapo r lock issues. thanks in advance. do not archive Ben Haas N801BH www.haaspowerair.com -- BELTEDAIR@aol.com wrote: Dear List:I have just gotten in on the tail end of this problem, but we have been working with people to come to a solution. We found the fuel s elector valve on low wing planes to be leaking air around the shaft but not leaking fuel. IF it were a high wing with a lot of head pressure fue l would seep out. But on low wing planes fuel does not seep out but air in. We built a manometer to prove the theory. We changed the .06 cent "O "ring around the shaft then put a drop of engine oil to make sure it did not pull in. We experienced engine roughness at high power settings ret urning to normal at lower power settings. If the aux fuel pump were turn ed on, it made the condition worse. In early 2006 we went back 5 years i n the NTSB files and found 99 instances where the engine quit then would run when it was removed from the wreckage. Fuel injected engines are wo rse due to the high suction. It equates to putting a hole in a straw and trying to drink. This was found on the "Imperial" type valve. This valv e was and is used in most GA and experimetal craft.Jess AOL now offers free email to everyone. Find out more about what's free f ======================== ======================== ======================== ======================== ======

Jess makes a good redrive unit and lives where is is" hot" in t he summer, in fact it is in the 90's down there now. YUCK.  Jess,I am assuming you are running mogas in your V-6 Chevy.If so have you ever had a vapor lock condition in the extreme heat of Las Vegas?  I made a test of mogas on my beast last year and it hiccuped at 13,000 a nd 45f degrees.  That got my attention but I safely made it back on the ground.I am not sure the fuel was the problem though because I made some other changes at the same time trying to get the oil cooler t o shed more heat and probably elevated the under cowl temp too much whic h heated up the fuel lines going to the carb. Plane goes up to 17,999 ms l perfectly on 100LL. I would like to hear stories from people on past e xperiences of runnig mogasand vapor lock issues.

thanks in advance.

do not archive


Ben Haas
N801BH
www.haaspowerair .com

-- BELTEDAIR@aol.com wrote:

Dear List:
I have just gotten in on the tail en d of this problem, but we have been working with people to come to a sol ution. We found the fuel selector valve on low wing planes to be leaking air around the shaft but not leaking fuel. IF it were a high wing with a lot of head pressure fuel would seep out. But on low wing planes fuel does not seep out but air in. We built a manometer to prove the theory. We changed the .06 cent "O"ring around the shaft then put a drop of engi ne oil to make sure it did not pull in. We experienced engine roughness at high power settings returning to normal at lower power settings. If t he aux fuel pump were turned on, it made the condition worse. In early 2 006 we went back 5 years in the NTSB files and found 99 instances where the engine quit then would run when it was removed from the wreckage. Fu el injected engines are worse due to the high suction. It equates to put ting a hole in a straw and trying to drink. This was found on the "Imper ial" type valve. This valve was and is used in most GA and experimetal c raft.
Jess



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________________________________ Message 5 _____________________________________ Time: 05:33:56 PM PST US From: "Gene Smith" Subject: Engines-List: Fuel pump tests OK, I hate to mention this because I haven't tried it myself...I used to use mogas in my RV-4(Lyc. 0320/160) and lots of folks at OSH do the same, now I only use 100LL in the summer, S. Tx is just too hot, plus the additives in mogas scare me, and as you know some companies are using 10% ethanol, and don't count on the pump to be marked as such. In a discussion about vapor-lock and etc., this one builder showed me what he did to prevent V/L...He sprayed the fuel pump(mechanical), fuel lines, and gascolator with a thick coating of SPRAY INSULATION FOAM all the way to the fire-wall...He did a neat job of applying the goop...I assume he used some form of shielding while spraying because there was no overspray anywhere else...I don't know if he sprayed the boost pump or not, he didn't mention it or show it to me...I asked about working on the units, and he said no problem, you use a knife and cut the foam away so you can get a wrench on the nuts and bolts or a screwdriver on the screws...When you get through, you simply squirt it some more with foam. Some of you experts out there must have an opinion on this or maybe some sort of experience in this area. I don't advocate this for anyone out there, and I repeat, I have never used this foam or a insulated wrap........Good Luck........................CHEERS!!!!................................Gen e Smith, 1994 RV-4. ----- Original Message ----- From: n801bh@netzero.com To: engines-list@matronics.com Sent: Friday, March 16, 2007 3:05 PM Subject: Re: Engines-List: Fuel pump tests Jess makes a good redrive unit and lives where is is" hot" in the summer, in fact it is in the 90's down there now. YUCK. Jess,I am assuming you are running mogas in your V-6 Chevy.If so have you ever had a vapor lock condition in the extreme heat of Las Vegas? I made a test of mogas on my beast last year and it hiccuped at 13,000 and 45f degrees. That got my attention but I safely made it back on the ground.I am not sure the fuel was the problem though because I made some other changes at the same time trying to get the oil cooler to shed more heat and probably elevated the under cowl temp too much which heated up the fuel lines going to the carb. Plane goes up to 17,999 msl perfectly on 100LL. I would like to hear stories from people on past experiences of runnig mogasand vapor lock issues. thanks in advance. do not archive Ben Haas N801BH www.haaspowerair.com -- BELTEDAIR@aol.com wrote: Dear List: I have just gotten in on the tail end of this problem, but we have been working with people to come to a solution. We found the fuel selector valve on low wing planes to be leaking air around the shaft but not leaking fuel. IF it were a high wing with a lot of head pressure fuel would seep out. But on low wing planes fuel does not seep out but air in. We built a manometer to prove the theory. We changed the .06 cent "O"ring around the shaft then put a drop of engine oil to make sure it did not pull in. We experienced engine roughness at high power settings returning to normal at lower power settings. If the aux fuel pump were turned on, it made the condition worse. In early 2006 we went back 5 years in the NTSB files and found 99 instances where the engine quit then would run when it was removed from the wreckage. Fuel injected engines are worse due to the high suction. It equates to putting a hole in a straw and trying to drink. This was found on the "Imperial" type valve. This valve was and is used in most GA and experimetal craft. Jess ------------------------------------------------------------------------- ----- AOL now offers free email to everyone. 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