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  #11  
Old 06-06-2017, 06:13 PM
ALMARTON ALMARTON is offline
 
Join Date: Mar 2010
Location: BRAZIL
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Quote:
Originally Posted by rv7charlie View Post

...

If you haven't set the mag (ignition) timing before, get someone with experience to bring their mag timing 'buzz box' & work with you, or let your mechanic do it. It's not hard, if you know how to do it. If you don't, you could do some real damage.

Did you re-fly the test at wide open throttle, leaned for best power (not an EGT number, but actual best power, as observed on the airspeed indicator), and *2700* rpm? Until you do, you're not making 75% power at that altitude (unless you're running a turbo).

Hope that helps,

Charlie
I'will ask them to do that (mag timing) and after I will do the open throttle test after also! May take a while cause at the present the fuel injection system is up for recalibrating and cleaning...


Quote:
Originally Posted by rzbill View Post
Alexandre,
For clarity to the group, please specify how you are determining % power.
Is it from a Lycoming chart or graph showing MP and RPM or from an EFIS display that was programmed by the original builder?
I do read it on my Garmin G3X Touch ...


Well something came up to me now I will ask the mechanic but would like your opinion piece of advice also off course.

Despite the fuel pump leaking into the oil sump I did not notice on pre flight check no alteration at all on oil level , it did not increased (as one would suppose - where all that fuel consumed would be ?)!

I think the presence of oil in the sump due to the fuel pump to justify such great consumption must have been in great quantities what would be noticeable checking oil level in pre check flight but it was not...

So I suspect the real reason for the high consumption was excess fuel being injected on the nozzles or an imperfect burn on the chamber thus great part of the excess not burnt fuel was being expeled throug exhaust valves and just a few getting washed up into the oil sump, not enough to increase noticeably the oil level but enough to dilute oil...

That was progressive and got worse into the last few hours of operation (recent get too bad). That would explain a relatively lower CHT I've been having ...

That is my theory! The mechanic could have thought the pump was the main issue but it does not sound right ... the level of gas consumed was too high to be stored only in the oil sump... for me is excess fuel not all of it burnt...
__________________
Alexandre "neck" Marton
Brazil
RV7A (8/2015 built by FLYER)
Lycoming 180 HP - YIO-360-M1B, Hartzell C2YR-1BFP/F7497 72, Garmin panel - G3X Touch, GTN650, GTS800, WX-500, BATT CONCORDE RG-25XC AEROBATIC SEALED.
-------------
Others: RV9A
Lycoming XIO320-D1A, Hartzell HC-C2YL-1BF/F7663-4 , CS GOVERNOR MTV-12-B, DYNON D180
AND GARMIN AVIONICS
(Sold with aprox 300hrs flown from Dec/2010 -- JUN/2014)

Last edited by ALMARTON : 06-06-2017 at 06:16 PM.
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  #12  
Old 06-06-2017, 06:24 PM
Ron B. Ron B. is offline
 
Join Date: Nov 2007
Location: Yarmouth, Nova Scotia
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Quote:
Originally Posted by ALMARTON View Post
Only AVGAS 100/130 LL ! But I do suspect from the dealers somehow adulterating it for profit...

Anyway the thing I cannot understand yet is HOW a failure on the mechanical fuel pump could pour gasoline into the engine oil sump...I thought the lines were very separated... Does anyone can explain me that?
If you suspect the fuel might not be top quality, could that be the cause of the seal failure in the fuel pump?
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RV-10 SOLD
RV-14 Flying
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  #13  
Old 06-06-2017, 08:32 PM
airguy's Avatar
airguy airguy is offline
 
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Quote:
Originally Posted by ALMARTON View Post
Well something came up to me now I will ask the mechanic but would like your opinion piece of advice also off course.

Despite the fuel pump leaking into the oil sump I did not notice on pre flight check no alteration at all on oil level , it did not increased (as one would suppose - where all that fuel consumed would be ?)!
When you crank up at the start of a flight the fuel starts leaking into the crankcase, and starts to accumulate. As you fly and the oil reaches full temperature the fuel in the oil evaporates as fast as it enters. When you land and shut down, the oil and the engine are still hot and most, if not all, of the fuel that is left in the oil will evaporate as it sits on the ramp and cools down. It's entirely possible you would not notice a change in the oil level - but a laboratory analysis of the oil will show greatly increased levels of lead in the oil from the 100LL contamination.
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Greg Niehues - VAF 2017 dues paid
Garden City, TX
N16GN flying! http://websites.expercraft.com/airguy/
Built an off-plan 9A with too much fuel and too much HP. Should drop dead any minute now.
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  #14  
Old 06-07-2017, 04:06 AM
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rzbill rzbill is offline
 
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Quote:
Originally Posted by ALMARTON View Post
I do read it on my Garmin G3X Touch ...
Until you confirm the readings by checking the power levels predicted by the IO-360-M1B Lycoming performance charts, treat the Garmin data as unreliable. It must be programmed by the user. I suspect that programming is wrong and it is showing power levels above actual.

**** EDIT**** On review of your earlier post about power levels I am positive that you are not at the power level displayed by the Garmin. For one example, it is not possible to go from 65% to 75% with an RPM change of 2400 to 2500. It takes more of a change. Additionally, at 8000 DA you MUST be at 2700 RPM to get 75% power with only 21.6 MP.



You have talked about the fuel pump. If memory serves, there are two flexible diaphagms separated by a gap in the pump. The gap leads to the fuel pump "overflow" or drain. Fuel comes out the drain if the first diaphragm fails. Second diaphagm continues to protect the crankcase. I assume you have seen considerable fuel coming out of the drain????
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Bill Pendergrass
RV-7A: Flying since April 15, 2012. 650hrs
YIO-360-M1B, mags, CS, GRT H1s & A/P, Navworx
Unpainted, polished....kinda'
My RV Construction Page

Last edited by rzbill : 06-07-2017 at 04:23 AM.
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  #15  
Old 06-07-2017, 05:19 AM
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swisseagle swisseagle is offline
 
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Is your fuel flow meter calibrated correctly? They can have different readings due to installation differences.

Does the USG used correspond with the amount you have to refill?
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Dominik

RV-7A, TMX-IO-320, FM-150, Sensenich FP
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  #16  
Old 06-07-2017, 08:23 AM
ALMARTON ALMARTON is offline
 
Join Date: Mar 2010
Location: BRAZIL
Posts: 130
Default Summarizing the help and findings so far

Folks, these google photos link show a video and pics of the disassembling of the fuel pump
where they detected the presence of gasoline in the oil by the aspect of the sample during a
routine oil change...

https://goo.gl/photos/bZpgHHfAyQjByk728

Before finding that pump failure we where thinking that thee high consumption was due to a failure of settings
on either the fuel injector system (AVSTAR) or the divider or some difference on the injection nozzles or a combination
of all those.

So the main purpose of the maintenance where to sack the fuel injection, divider and nozzles for re-calibrating,
cleaning and check. The oil change where just to seize the opportunity of this maintenance and doing also oil check...
in the end it seems to have led us to one or the sole real reason of the problem

I consider myself a bit of a layman on matters of engine (if compared with most of you) and so this thread is to me
a great lecture and I am learning a lot.. but I have still some doubts lets adress them:

Quote:
Originally Posted by Ron B. View Post
If you suspect the fuel might not be top quality, could that be the cause of the seal failure in the fuel pump?
Ron, yes. Our main suspect is that adulterated fuel (some malicious merchant has subtituted gasoline with some solvent for profiting).
Having somehow the solvent attacked the rubber in the pump... But reading this:

Quote:
Originally Posted by rzbill View Post
You have talked about the fuel pump. If memory serves, there are two flexible diaphagms separated by a gap in the pump.
The gap leads to the fuel pump "overflow" or drain. Fuel comes out the drain if the first diaphragm fails.
Second diaphagm continues to protect the crankcase. I assume you have seen considerable fuel coming out of the drain????
After enlighted by Ron I'm at doubt if some solvent could have gone through 2 layers of diafragm rubber and start to suspect
poor material conditions and not some solvent could have done all that in such a few time.
Remember I stated this is a the 143 hours engine (fuel pump and all parts) bought zero hours with the engine straight form Lycoming itself.
[/quote]

From reading Airguy:

Quote:
Originally Posted by airguy View Post
When you crank up at the start of a flight the fuel starts leaking into the crankcase, and starts to accumulate.
As you fly and the oil reaches full temperature the fuel in the oil evaporates as fast as it enters. When you land and shut down, the oil
and the engine are still hot and most, if not all, of the fuel that is left in the oil will evaporate as it sits on the ramp and cools down.
It's entirely possible you would not notice a change in the oil level - but a laboratory analysis of the oil will show greatly increased
levels of lead in the oil from the 100LL contamination.
I still don't understand how the oil lines being a closed system (the way I see it) how could it could after gasoline leaked inside oil sump
have evaporated so much fuel (the consumption where above the standard at least a 1 gal/h) during operations in a closed system. Such evaporation
should be so high for no oil level increase be noted on pre flight checks. To me as layman such evaporation on a closed system as I imagine oil
line is to be is unlikely. I would have to notice some oil level increase for the mixture with gasoline.

That's why I still suspect that most of the loss of gasoline causing the high consumption may have to do with a incomplete burn
in the combustion chambers , the major part of the gasoline being expeled in the exhaust and some being whased out into the
oil by the pistons. That is more easy to me to figure out but I may be wrong.

So I think tha regulating the fuel injector system (AVSTAR), divider and cleaning nozzles I may have a better spread. And I also
start to think that what a key advice to enhance mixture burnt and fuel economy maybe on rv7charlie writings...


Quote:
Originally Posted by rv7charlie View Post
Sounds like you've solved the excess fuel issue; now the speed issue:
If you haven't set the mag (ignition) timing before, get someone with experience to bring their mag timing 'buzz box' & work with you, or let your mechanic do it.
It's not hard, if you know how to do it. If you don't, you could do some real damage.

I stil have lot to check... but I understand a lot of fuel economy has to be gained from the adjustments and fixes are being and also some
power gain, to put it in cruise conditions not only more economical in fuel matters but also more close on performance numbers from the standard VANs specs.

I will keep you dully posted but any opinions , advices or critics are very welcome and great help solve the issue. And I am spending but learning a lot so
I don't mind the problem (as long as it will get fixed, I hope ).

Many many thanks!
__________________
Alexandre "neck" Marton
Brazil
RV7A (8/2015 built by FLYER)
Lycoming 180 HP - YIO-360-M1B, Hartzell C2YR-1BFP/F7497 72, Garmin panel - G3X Touch, GTN650, GTS800, WX-500, BATT CONCORDE RG-25XC AEROBATIC SEALED.
-------------
Others: RV9A
Lycoming XIO320-D1A, Hartzell HC-C2YL-1BF/F7663-4 , CS GOVERNOR MTV-12-B, DYNON D180
AND GARMIN AVIONICS
(Sold with aprox 300hrs flown from Dec/2010 -- JUN/2014)
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  #17  
Old 06-07-2017, 09:38 AM
airguy's Avatar
airguy airguy is offline
 
Join Date: Oct 2006
Location: Garden City, Tx
Posts: 3,727
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Quote:
Originally Posted by ALMARTON View Post


I still don't understand how the oil lines being a closed system (the way I see it) how could it could after gasoline leaked inside oil sump
have evaporated so much fuel (the consumption where above the standard at least a 1 gal/h) during operations in a closed system. Such evaporation
should be so high for no oil level increase be noted on pre flight checks. To me as layman such evaporation on a closed system as I imagine oil
line is to be is unlikely. I would have to notice some oil level increase for the mixture with gasoline.

That's why I still suspect that most of the loss of gasoline causing the high consumption may have to do with a incomplete burn
in the combustion chambers , the major part of the gasoline being expeled in the exhaust and some being whased out into the
oil by the pistons. That is more easy to me to figure out but I may be wrong.
The crankcase is not a closed system, it is ventilated to allow combustion gases that leak past the piston rings to escape the crankcase, otherwise it would build up pressure until you pop out the crankshaft main seals at the front of the engine. There is a crankcase ventilation line near the top rear of the engine that should be routed down to the bottom rear of the cowling near the exhaust pipe, that dumps the "blowby" gases out of the airplane. If there is fuel in the oil, as the oil heats up this fuel will evaporate and be dumped out of the crankcase along with the blowby gasses from the cylinders.

The pressurized oil system is closed, yes - from the pump all the way until dribbles back down out of the bearings back down into the bottom of the sump for the pump to pick up again - but the entire crankcase itself and the unpressurized oil in it is ventilated to the atmosphere.
__________________
Greg Niehues - VAF 2017 dues paid
Garden City, TX
N16GN flying! http://websites.expercraft.com/airguy/
Built an off-plan 9A with too much fuel and too much HP. Should drop dead any minute now.
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  #18  
Old 06-07-2017, 10:32 AM
ALMARTON ALMARTON is offline
 
Join Date: Mar 2010
Location: BRAZIL
Posts: 130
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Quote:
Originally Posted by airguy View Post
The crankcase is not a closed system, it is ventilated to allow combustion gases that leak past the piston rings to escape the crankcase, otherwise it would build up pressure until you pop out the crankshaft main seals at the front of the engine. There is a crankcase ventilation line near the top rear of the engine that should be routed down to the bottom rear of the cowling near the exhaust pipe, that dumps the "blowby" gases out of the airplane. If there is fuel in the oil, as the oil heats up this fuel will evaporate and be dumped out of the crankcase along with the blowby gasses from the cylinders.

The pressurized oil system is closed, yes - from the pump all the way until dribbles back down out of the bearings back down into the bottom of the sump for the pump to pick up again - but the entire crankcase itself and the unpressurized oil in it is ventilated to the atmosphere.

Greg "Airguy" excellent explanation and arguments I did not know that... I' almost agreeing with you.

But reason with me. See If I don't have a point when I still think that if there was such quantities of gas being drop entirely in the sump, the dilution would be such that the lubrication would be so compromised that the temperatures would show an noticeable increase... We are talking of each hour at least 4 litres of gasoline being leaked into sump.

That was not what I saw. There was no temperature increase. On the contrary the EGTs where very cool, CHTs history looking colder on the last few flights never reaching 399F not even on takeoff full power period (as was before). CHT drop in cruise from a log history of 385F average to 373F in cruise settings!

So I still think based on that the fuel loss where in combustion chamber... this pump leakage is something but not the main cause.

By the way ALMOST ALL LOGS to this plane , since 0 hours to few days ago are here in the link I share with you for your appreciation :

http://cirrusreports.com/flights/PRZTI

* Just an observation , it does lack the last 4 hours of flight in the logs, before entering mantenance. Those las 4 hours the CHTs operated considerable colder than the logs you see there in the link, the leg I flew to maintenance I remember it going at 363F on the CHT at 22 MAP and 2450 rpm. Ok it is winter here now... but the temperature of the day here nowadays is not that cold and it is on the human confort zone when comparing to summer days. I think 66F now versus 95F on summer.

What do you thing in the view of that?

Aiguy and others your knowledge of the engine works I realized is far beyond mine but you did not have yet this data to bias your conclusions. Considering those do you still think it may be the fuel pump leakage the main reason for high fuel consumption?
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Alexandre "neck" Marton
Brazil
RV7A (8/2015 built by FLYER)
Lycoming 180 HP - YIO-360-M1B, Hartzell C2YR-1BFP/F7497 72, Garmin panel - G3X Touch, GTN650, GTS800, WX-500, BATT CONCORDE RG-25XC AEROBATIC SEALED.
-------------
Others: RV9A
Lycoming XIO320-D1A, Hartzell HC-C2YL-1BF/F7663-4 , CS GOVERNOR MTV-12-B, DYNON D180
AND GARMIN AVIONICS
(Sold with aprox 300hrs flown from Dec/2010 -- JUN/2014)

Last edited by ALMARTON : 06-07-2017 at 10:38 AM.
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  #19  
Old 06-07-2017, 12:27 PM
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airguy airguy is offline
 
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Posts: 3,727
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I'm not saying that all your fuel went into the crankcase instead of being burned as a rich mixture. I'm saying that it's entirely possible that a good portion of it went into the crankcase and evaporated out without you noticing it.

Yes, it will dilute the oil, but not necessarily to the point that you'll notice increased oil temperature during operation. In fact, the opposite may be true to some degree - until you reach a point of dilution where increased friction causes increased heating, you'll actually see a lower temperature on the oil due to the cool fuel diluting it and the evaporation of that fuel carrying away heat.
__________________
Greg Niehues - VAF 2017 dues paid
Garden City, TX
N16GN flying! http://websites.expercraft.com/airguy/
Built an off-plan 9A with too much fuel and too much HP. Should drop dead any minute now.
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  #20  
Old 06-07-2017, 02:08 PM
N427EF N427EF is offline
 
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Quote:
you'll actually see a lower temperature on the oil due to the cool fuel diluting it and the evaporation of that fuel carrying away heat.
I think you nailed it, particularly where you state that evaporation causes cooling.
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RV-10 Flyer 400 plus hours
Over 2500 Gallons of E10 mogas burned
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