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Filter Maintenance

michjor

Member
The oil filter maintenance/replacement scheduled with oil changes after (x) hours is pretty defined.

Suggestions for other filter/fuel management maintenance.
How many fuel filters do folks typically put inline?
How frequently do you change them (vs inspection)?
How often do you check/replace the fuel flow sensor?
Air filters?
Any other filters/sensors critical to regular maintenance I can add to the standard conditional and hourly maintenance routine?

Thanks
 
Answers:
- One fuel filter (AirFlow Performance). Inspected at each Condition inspection (never had a spec in it but still check). Never replaced.
- AirFilter (K&N). Cleaned each Condtion inspection. The RV-8A and RV-10 had the FAB - that filter needed replacement every 4-5 years as it tended to deform. The jury is still out on the RV-8 (snorkel) filter on how long it will go before replacement.
- Fuel Flow sender. Never touched.
- Other engine sensors - replace if they go bad. Other than that leave them alone.
- Throttle body fuel finger strainer. Inspected at first Condition inspection. After that I recommend leaving it alone unless you have a dirty inline filter - if so remove and clean.
- Oil Sump finger strainer. Inspect at first Condition inspection. After that as deemed necessary by what you find in the oil filter (or perhaps once every 2-3 years). Note - I’ve pulled these many times and each time found them to be pristine - and it is a messy job. Make sure you have a new strainer copper gasket in hand before proceeding (note - not the same copper gasket as used on spark plugs).
- Fuel Injectors - I started out removing, cleaning and reinstalling these. After some education from the various Mike Busch videos I now leave them in and just give the air screens a shot of carb cleaner.

Carl
 
How many fuel filters do folks typically put inline?

One, between the electric fuel pump and the mechanical fuel pump, in the cabin.

How frequently do you change them (vs inspection)?

On condition - which is probably every 2000-4000 hours - these are stainless steel filters that will probably last forever. I have mine on a 100hr/1year cleaning schedule.

How often do you check/replace the fuel flow sensor?

If it dies, I will replace it. I use it of course every flight. If it stops working, and does not block, it's not a safety of flight issue.

Air filters?

I have mine on a yearly/100hr cleaning schedule. So far I've been lazy and have just replaced it, but now have a cleaning kit and will clean them when I get two to clean.

One of these is new, the other was removed during the annual. Granted, I don't live in the Sahara.

IMG_4719.jpg


Any other filters/sensors critical to regular maintenance I can add to the standard conditional and hourly maintenance routine?

Don't forget the big oil intake screen at the bottom rear right of the engine (at least on my io360).
 
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Some good advice here -)
Is there another air filter to suit RV8 with the intake below the cowl? I can’t source one here, seems they are very rare!
 
Don't forget the finger screen/filter in the FI servo. Most carbs have one also. It should be checked and cleaned every year. If the rubber in your fuel hoses ever starts to break down, this is where the debris will collect and it is not that big of a filter. Therefore, annual inspections are crritical.
 
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Answers:
- One fuel filter (AirFlow Performance). Inspected at each Condition inspection (never had a spec in it but still check). Never replaced.
- AirFilter (K&N). Cleaned each Condtion inspection. The RV-8A and RV-10 had the FAB - that filter needed replacement every 4-5 years as it tended to deform. The jury is still out on the RV-8 (snorkel) filter on how long it will go before replacement.
- Fuel Flow sender. Never touched.
- Other engine sensors - replace if they go bad. Other than that leave them alone.
- Throttle body fuel finger strainer. Inspected at first Condition inspection. After that I recommend leaving it alone unless you have a dirty inline filter - if so remove and clean.
- Oil Sump finger strainer. Inspect at first Condition inspection. After that as deemed necessary by what you find in the oil filter (or perhaps once every 2-3 years). Note - I’ve pulled these many times and each time found them to be pristine - and it is a messy job. Make sure you have a new strainer copper gasket in hand before proceeding (note - not the same copper gasket as used on spark plugs).
- Fuel Injectors - I started out removing, cleaning and reinstalling these. After some education from the various Mike Busch videos I now leave them in and just give the air screens a shot of carb cleaner.

Carl

Maybe you should have said "my opinion"?

Anyway my suggestions:
The fuel filter in the fuel servo is normally finer than the primary fuel filter so I check it religiously ever annual.
Sump screen: check every annual, the spin on filter catches the small stuff the sump screen catches the big stuff (I once pulled a bunch of broken lifter bodies out of the sump while the spin on filter was clean).
I don't waste time cleaning air filters, if their dirty I replace them.
Oil: I change oil every 25 hrs and oil filter every other change (50 hrs).
 
Don't forget the finger screen/filter in the FI servo. ... It should be checked and cleaned every year. If the rubber in your fuel hoses ever starts to break down, this is where the debris will collect and it is not that big of a filter. Therefore, annual inspections are crritical.

If it's Precision Airmotive, then that's NOT what the manual recommends.

12.2...The fuel filter inside the servo...does not need to be checked or cleaned unless it is suspected that contaminates (sic) have enter the fuel line after the aircraft's fuel filter.
 
Maybe you should have said "my opinion"?

Anyway my suggestions:
...
Oil: I change oil every 25 hrs and oil filter every other change (50 hrs).

Why are you changing the oil twice as often as the Lycoming manual recommends? Certainly doesn't hurt anything, just twice as expensive for what gain?
 
If it's Precision Airmotive, then that's NOT what the manual recommends.

To each his own. To others, be advised that the screen that I mentioned is very fine and relatively small. It will pick up very small debris. Your big risk here is that if the rubber hoses or rubber diaphragms in the fuel pump start to break down and sluff off rubber debris, this strainer can quickly become clogged and result in engine stoppage. If you have another way to confirm that your hoses and diaphragms are not breaking down, more power to you. This step takes literally 3 minutes and is cheap insurance for those other than RV7A flyer. What is the point of a condition inspection if you are not inspecting the condition of things that could result in engine stoppage.

Larry
 
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Why are you changing the oil twice as often as the Lycoming manual recommends? Certainly doesn't hurt anything, just twice as expensive for what gain?

Because a clean engine is a happy engine, it's the cheapest thing you can do to your engine to make it last longer.

To each his own. To others, be advised that the screen that I mentioned is very fine and relatively small. It will pick up very small debris. Your big risk here is that if the rubber hoses or rubber diaphragms in the fuel pump start to break down and sluff off rubber debris, this strainer can quickly become clogged and result in engine stoppage. If you have another way to confirm that your hoses and diaphragms are not breaking down, more power to you. This step takes literally 3 minutes and is cheap insurance for those other than RV7A flyer,

Larry

Agree with Larry, plus the standard pre-filter from AFP I believe is 140 micron while the servo screen is closer to 40 micron, and not very big.
 
AFP filter

I had forgotten the filter in the fuel servo - thanks for the reminder.

Here's what's in the documentation for the AFP fuel injection systems:

https://airflowperformance.com/wp-content/uploads/2018/12/API-Installation-Service-Manual-9003.pdf

The fuel controller incorporates a 75 micron filter in the fuel inlet fitting. If you are unsure of the type of fuel filtration to use for your application, contact Airflow Performance. This is a very important component of the fuel system and will effect the correct operation of the fuel injection system if sized incorrectly. All Airflow Performance fuel filters are nonrelieving type.

These fuel controls incorporate a 70 to 75 micron nominal rated composite fuel filter which can be removed for cleaning by removing the inlet fitting. This is a-relieving filter. The inlet filter fitting can be either a straight (shown) or 90-degree fitting. Cleaning the filter element is best performed in a sonic cleaner with soap and water. Blow dry with compressed air.

After the first 3 to 5 hours of engine operation after installing the fuel controller on a new installation, remove and clean all fuel filters and strainers in the aircraft fuel system. Repeat after 10 hours of operation, 25 hours of operation and every 50 hours of operation there after. Fuel control inlet filter should be inspected and cleaned (sonic cleaner recommended) at condition inspection.

AFP Inlet Fuel Filter.png

AFP Inlet Fuel Filter - pg22.png

Looks like I better buy a sonic cleaner!
 
Because a clean engine is a happy engine, it's the cheapest thing you can do to your engine to make it last longer.

OK. So why not change it every 10 hours? Or every 5? Or after every flight?

I'm comfortable with doing what the manufacturer says in their manual, and while anyone can do whatever they want, I just think if you're going to advise people to deviate from the manufacturer's instructions, there should be very good reasons supported by data to do so.

I'm not being argumentative, I promise. But, e.g., the fuel filter...PA says don't need to remove it and clean unless contamination is suspected. And there are very good reasons NOT to do unnecessary removal, inspection, and reinstallation: Maintenance-induced failures (MIFs). Every time you monkey around with the fuel system, there's a *chance* of making an error in a critical system on the aircraft. So there should be good, solid rationale based on data to support the deviations, IMO.
 
Do whatever makes you happy.

I fall into a category of about 75 hrs/yr generally so 25hrs is approx every 4 months for me.

From Lyc Tech Tips (maybe this qualifies as "Data"):

a. 50-hour interval oil change and filter replacement for all
engines using a full-flow filtration system.
b. 25-hour interval oil change and screen cleaning for all
engines employing a pressure-screen system.

c. A total of four months maximum between oil changes for
either of the systems discussed under a. and b., even if the
engine is not flown.


Reports from aircraft owners continue to indicate that trouble-free
operation through TBO is most often obtained with engines subjected
to frequent oil change intervals. Absurd as it may seem, an engine
which does not fly regularly should have the oil changed at more
frequent flight time intervals than one that does fly regularly.


Practically every one of my customers fly's around 50hrs/yr give or take, they inevitably return each cond insp without having changed the oil or filter for the full year with the 50hr excuse. Having been a mechanic all my life I've seen the insides of plenty of engines, you can probably guess why I do what I do and why I continue to recommend it.
 
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Changing only the oil alone takes about 5 mins - literally - if you use a vacuum oil extractor in the dipstick.
 
I’m with Walt

I follow the same schedule that Walt uses (not surprising since he’s my brother).

I always remove the cowl and do a complete FWF check when I change the oil. So for me, changing the oil is my excuse/motivation to do a FWF check and an opportunity to bond with my plane.
 
But, e.g., the fuel filter...PA says don't need to remove it and clean unless contamination is suspected.

And Lycoming says not to run LOP. All sorts of guidance that isn't always best to follow, for those that know better.

'Your first "suspicion" may be the engine running poorly over the Rockies. I am not inherently against following MFR recommendations, but I don't agree with this one. There is simply no way to suspect a clogged filter prior to the engine complaining about it. Most cases that is just an engine that can't deliver full fuel for fuel power. Unfortunately that is a T/O situation, where a lean mixture can cause detonation.

Larry
 
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Oil is a cheap part of caring for the engine. I change the oil in the helicopter (IO-390) every 25 hours because it is running at 3100 RPM's all the time. That's a lot more power strokes with wear and tear on the oil.

On the Stearman, I change it every 25 hours as well. Yes, it turns slower, but the oil doesn't nearly run as hot as I'd like it to (normally 160), so it's worth changing.

On the 10, I change it every 30-35 hours. It's flown 200+ hours per year, and the oil always looks clean.

Yes, Lycoming says 50 hours. I would venture to say that 50 hours is OK for aircraft that are flown every day, like flight schools and corporate flying. I had heard once that Lycoming saw warranty costs increase after they started recommending 50-hr oil changes, but I can't find that reference now.

Like Walt, we see LOT of engines every week, usually to the tune of 3-5. The ones that are flown regularly and often have cleaner oil and seem to last longer.

Notice I said "flown." We have seen some that have been run on the ground for various reasons, and they are absolutely horrible inside, with lots of rust. It's imperative to fly it long enough to get the moisture out of the engine and the oil. The engine itself needs to be hot enough so that the combustion by-products are carried out of the crankcase via the breather line before they can condense back into the engine.


That's just our experience. Not an opinion. :)

Vic
 
Do whatever makes you happy.

I fall into a category of about 75 hrs/yr generally so 25hrs is approx every 4 months for me.

From Lyc Tech Tips (maybe this qualifies as "Data"):

a. 50-hour interval oil change and filter replacement for all
engines using a full-flow filtration system.
b. 25-hour interval oil change and screen cleaning for all
engines employing a pressure-screen system.

c. A total of four months maximum between oil changes for
either of the systems discussed under a. and b., even if the
engine is not flown.


Reports from aircraft owners continue to indicate that trouble-free
operation through TBO is most often obtained with engines subjected
to frequent oil change intervals. Absurd as it may seem, an engine
which does not fly regularly should have the oil changed at more
frequent flight time intervals than one that does fly regularly.


Practically every one of my customers fly's around 50hrs/yr give or take, they inevitably return each cond insp without having changed the oil or filter for the full year with the 50hr excuse. Having been a mechanic all my life I've seen the insides of plenty of engines, you can probably guess why I do what I do and why I continue to recommend it.

Ah, that's a bit different...IF the airplane is not flow 50 hours by 4 months time, then yes, I change oil and filter no matter what the hours. I wasn't advocating 50 hours in *all* circumstances such as a plane that flies less than that in 4 months.

But if it is flown more than that, then I go by the manufacturer's recommendation on my aircraft, and oil analysis at every change supports this. YMMV! :)
 
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