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inline fuel filter

B

bobnoffs

Well Known Member
i have a 10 micron filter just before my engine and a coarse finger strainer in my sump.
after building my tank i am sure there are going to be pieces of aluminum between flanges and tank wall etc. that i will never get out. i am sure pieces will go thru my finger strainer. i want to put an inline filter 100 microns between my sump and my pumps. at first i thought i should use a $130 aeromotive filter that has 60 inches of pleated stainless steel filter. after thinking about it i am wondering about a $40 filter that probably uses [ i don't know for sure] a filter disc, 1 inch diameter like in a gascolator. i am looking at the cheaper filter as i will probably ground the engine 10-20 hrs before i ever fly. a couple filter checks in that period should catch most of the pieces and give me an indication of what to expect in the future.
opinions?
 
Disregarding the fineness of the filter element, ponder how much (little) it would take to block that overall filter area. Then ponder the pressure drop (as in vapor lock) if that filter area is even partially blocked. Not just now, but at any time in the future.

Not saying to spend $140 on a filter; just consider the type of product.
 
I've got Summit Racing inline filters between my sump and pump, and yes there is a surprising amount of "stuff" that gets dumped out of them on each annual. Most of it appears to be just atmospheric dust with an occasional piece of insect and the odd small aluminum shaving.
 
were are filters?

I have been thinking about adding two in line filters after the tanks but before the fuel selector is this a common place? and if people have this do you run the tank empty before taking the filter out to clean?
 
Clean the tanks

No matter what fuel filter set up you use, you should flush the tanks.

Take the tanks off the wings, cap off the fuel line connections, add a few inches of 1/4? tubing to the vent attachment, then add 5 - 10 galllons of 100LL. Slosh the fuel around and drain via the sump fitting using a 1/8? pipe nipple, some plastic tubing and a cheap see through inline filter. Drain to clean gas jugs. Use the filtered gas to repeat until satisfied the fuel is running clean.

With the tanks off you can now let 5-10 gallons of gas sit in them (tank vented) for a couple of weeks to find out if you have any weeping rivets. Rotate the tank on the bench in various positions to check all rivets. Weeping rivets will not be found doing standard tank leak checks.

Carl
 
I bought some of the Floweze 3000 series filters for both pre-pump and post pump filters. Do a search, they were recommended by others here on the site. They end up being about $90/each. They are available with alcohol safe prints too. You can buy them direct from Floweze and they are a little cheaper than the aeromotive filters. Still not cheap though.
 
I also have the Summit Inline racing filters , one on each before the selector valve. They are mounted forward of the spar behind the cover plate. Have found brown/ tan textile material in both at different times. I'm assuming its accumulation of filter element lint found in the 100LL pump distribution systems. I have seen Lo alarm( 1 PSI) on the fuel press. Was on one side and the boost pump restored it. Since then has been annual thing to just replace the thimble ceramic element. 0 320 D2J (carb)
 
bobnoffs said:
i have a 10 micron filter just before my engine..
Click to expand...
I'm not familiar with RV-12 engines but, just offhand, that seems like overkill to me. The purpose of that filter is to keep particles from clogging up fine passages in your carburetor(?) and I really doubt that any passages are as small as .00039". I would recommend "defense in depth". On my Lancair, I have the usual finger strainers in the tanks to catch the big chunks, a clear WIX automotive paper fuel filter between my wing tanks and header tank (the engine runs off the header tank), a brass screen in my gascolator, a finer screen in my Facet boost pump, and a really fine finger screen at the carburetor inlet. After the initial flight test period, I never see any debris in any of them during annual inspections. You can also install a temporary filter for the initial flight testing to catch the inevitable "junk".
 
Summit filters

airguy said:
I've got Summit Racing inline filters between my sump and pump, and yes there is a surprising amount of "stuff" that gets dumped out of them on each annual. Most of it appears to be just atmospheric dust with an occasional piece of insect and the odd small aluminum shaving.
Click to expand...

+1.

I also have a 10 micron filter after the gascolator to keep really fine stuff out of the Rotec TBI. So far after 90 hrs and 2 inspection haven't found anything in it and always have steady fuel pressures and flows.

Al
 
We have a course 90 micron filter at the outlet of the header tank, prior to the dual fuel pumps. Then there is a 30 micron filter downstream of each pump, 3 filters total.
 
Bob, if you have access to the pickup in the tank, have you considered using an automotive style 'sock' type filter on the pickup? They are fine enough to protect injection pumps, and if properly installed, they will effectively last the life of the a/c, like they do in cars.
 
sock filters

rv7charlie said:
Bob, if you have access to the pickup in the tank, have you considered using an automotive style 'sock' type filter on the pickup? They are fine enough to protect injection pumps, and if properly installed, they will effectively last the life of the a/c, like they do in cars.
Click to expand...
I'm still challenging a scrappy entrepreneur to create a kit that uses automotive pumps in the tank with this kind of sock filter. While the standard aircraft design seems to work well for most, sure seems like the automotive design has a lot of advantages.
 
i do have access to the finger strainer. i have installed a 5.25'' hole over the sump. removing the sealed access cover may turn out to be no harder than going after the filter which i was intending to put in the tunnel in the baggage compartment.
any more specific name for this type of filter?
thanks.
 
A friend with a homebuilt aircraft, using a dual fuel pump configuration, only had the fuel filters located between the header tank, and the pumps. The fuel from the pump to the engine was not filtered as it had been filtered prior to going into the pump.

One pump self destructed sending bits and pieces into the fuel line which clogged the fuel rail. The engine barely was operating at this point, and he was able to make a successful landing at a nearby airport.

Everyone here already is aware of this, but the importance of pre and post pump filtration cannot be over stressed.
 
If you're talking about a more-or-less cube shaped tank, the possibilities are almost uncountable. Everything from something (if you want to include the pump) like
https://www.ebay.com/itm/Omix-Ada-17728-01-In-Tank-Fuel-Filter-Fits-70-86-CJ5-CJ6-CJ7-Scrambler/222367996371?epid=117997192&hash=item33c62a59d3:g:i2EAAOSwmuVaVZWJ&vxp=mtr
prosealed to the end of the pickup tube, to
https://www.ebay.com/itm/TANKS-INC-GPA-SERIES-IN-TANK-FUEL-PUMP-FOR-STEEL-TANKS-GPA-TBI-U2-HOT-RAT-ROD/222551337671?hash=item33d117eac7:g:dFsAAOSw9VZXPHj5&vxp=mtr
or
https://www.ebay.com/itm/FITech-Fuel-Injection-40019-Hy-Fuel-Single-Pump-In-Tank-Retrofit-Kit-Supports-Up/401369656977?hash=item5d737eee91:g:a~IAAOSwEZdaCmo4&vxp=mtr
or, for a lot less money,
https://www.ebay.com/itm/New-Fuel-Pump-Assembly-02-03-Avalanche-Escalade-ESV-EXT-Suburban-Yukon-XL-GAM273/171542454395?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649
and (I think) you can replace the actual pump with a Walbro turbine pump for about $80.00 if you want guaranteed quality.

For just the filter sock,
https://www.ebay.com/itm/5PC-Strainer-Fuel-Pump-Filter-For-TOYOTA-MAZDA-car-In-Tank-Fuel-Pump-11-0-1MM/201596029327?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649
or
https://smile.amazon.com/Filter-Strainer-Sock-Adapter-Bosch/dp/B00KTNAF12/ref=sr_1_4?ie=UTF8&qid=1518270988&sr=8-4&keywords=intank+fuel+filter+sock
or
https://smile.amazon.com/GMB-540-4020-Fuel-Pump-Screen/dp/B00P2HS602/ref=sr_1_7?ie=UTF8&qid=1518270988&sr=8-7&keywords=intank+fuel+filter+sock
are just two of hundreds of choices for just the filter sock. All the socks I've found so far require some type of adaptation, but hey, we're homebuilders; not assemblers, right?

IIRC, the 'Toyota' sock is what I've used. A -6 tube sleeve is a press-fit into the socket on the filter. I used fuel sealant to glue the tube sleeve on the -6 tubing, and then safety wired through the filter's attach eyelet.

Last (and for Mickey), here's what is out there for dual pumps. I don't think I'd ever pay this, but they are not much more expensive than the prefabbed 'aviation' pumps being marketed to us these days that use $60 pumps.
https://www.ebay.com/itm/Aeromotive-Phantom-Stealth-Dual-In-Tank-Fuel-Pump-Kit-ARO18309/253225268149?epid=1986009073&hash=item3af566f3b5:g:i4oAAOSwQS1Z8A~9&vxp=mtr
https://www.ebay.com/itm/Aeromotive-18309-Phantom-Dual-340-Stealth-In-Tank-Fuel-Pump-System-Up-to-2000hp/221733406371?epid=1634356186&hash=item33a05746a3:g:GD0AAOSw2tFab6gL&vxp=mtr
https://www.ebay.com/itm/Honda-Civic-92-00-Acura-Integra-Dual-Fuel-Pump-Hanger-Assembly-E85-Compatible/263308835854?hash=item3d4e6dfc0e:g:dSYAAOSwnTdaA1sb&vxp=mtr

There are dozens (probably hundreds) of choices for in-tank pump assemblies with just a single pump. Note the springs on most of them. Some will adjust over a quite wide range of vertical heights, and the springs keep the filter/pump assembly pressed against the bottom of the tank.

Happy hunting,

Charlie
 
beautiful assemblies

Those are some really nice looking pump assemblies. Just need Van's to bless one or to get someone to create a kit. Looks like they would work fine on the end of the tank just aft of where the sender is, or from the back.
 
I definitely would not run with just a small 10 micron filter. Your just asking for trouble. One tank of bad gas with debris and you risk an engine shutdown. The very fine filters are only for catching very fine debris that could clog very small passages. They are not large enough to stop big problems. You need a larger, courser filter to catch the bulk of debris. I don't believe it has to be an aviation filter, but I do believe in getting a large one. We have all heard stories about bad gas at airports and I feel better with a larger filter that will handle a lot of debris.

Larry
 
i have been looking at the socks, haven't gotten to the other links yet. seems to me to be a downside is that a sock doesn't capture the particle, just keeps it out of circulation. i would rather have my debris count in my tank slowly go down. the particle size that could do damage will fit thru my finger screen and be trapped with an inline just out of the tank.
haven't looked at the inlines much yet but now i will.
 
Don't know about how your tank's sump drain is set up, but the wing tanks I'm familiar with have the sump drain almost directly under the fuel pickup. Any trash sloshing around the sock will likely come out the next time the tank is sumped. Even if it doesn't, consider that something similar has been riding around doing its job for 20+ years in that junker somebody bought for their son that now has 217,000 miles on it with the 'sump' never having been drained.

The upside of the socks is that they don't get clogged. On the other hand, that 1" disk filter element mentioned earlier could easily be blocked with a very small quantity of trash.

But it's your plane and you need to do what you're comfortable with. Just thought I'd throw out some ideas for other options.

Charlie
 
rv7charlie said:
....Last (and for Mickey), here's what is out there for dual pumps. I don't think I'd ever pay this, but they are not much more expensive than the prefabbed 'aviation' pumps being marketed to us these days that use $60 pumps.
https://www.ebay.com/itm/Aeromotive-Phantom-Stealth-Dual-In-Tank-Fuel-Pump-Kit-ARO18309/253225268149?epid=1986009073&hash=item3af566f3b5:g:i4oAAOSwQS1Z8A~9&vxp=mtr
https://www.ebay.com/itm/Aeromotive-18309-Phantom-Dual-340-Stealth-In-Tank-Fuel-Pump-System-Up-to-2000hp/221733406371?epid=1634356186&hash=item33a05746a3:g:GD0AAOSw2tFab6gL&vxp=mtr
https://www.ebay.com/itm/Honda-Civic-92-00-Acura-Integra-Dual-Fuel-Pump-Hanger-Assembly-E85-Compatible/263308835854?hash=item3d4e6dfc0e:g:dSYAAOSwnTdaA1sb&vxp=mtr
....Charlie
Click to expand...

You can roll your own by using a 1979 Cadillac Seville aftermarket external pump (that's the pump our favorite vendors use) together with some fittings from Summit Racing or Airflow Performance to adapt it to AN plumbing.

Heinrich
 
Last edited:
I've got one of the Airtex pumps like you're talking about in my 'collection', but I like Walbro GSL393 pumps a lot more.
https://www.google.com/search?ei=RGN_Wry0J6y_jwTuoqMo&q=walbro+gsl393&oq=walbro+gsl393&gs_l=psy-ab.3..0j0i20i263k1.29469.32514.0.33708.6.3.0.3.3.0.149.435.0j3.3.0....0...1c.1.64.psy-ab..0.6.452....0.ErJOw1VYXbE
And much easier to adapt to a/n fittings.
https://www.ebay.com/p/Walbro-Inline-Fuel-Pump-Fitting-M10-X-1-to-6-an-Male-128-3039/1022214227
Same fitting for both ends.

Now, if you're really serious about in-tank pumps, the modules I linked to earlier are all turbine pumps; not roller-vane or gerotor pumps like the Walbro or Airtex. With turbine pumps and the proper PWM controller, you can have whatever pressure you want, measured at the fuel rail, referenced to MAP, and no return line. PWM isn't kind to gerotor & roller-vane pumps; tends to make them chatter & wear out quicker, according to engineers at Walbro.

Charlie
 
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