Air Flow Performance electric fuel pump filter

I wonder if those of you who have an injected engine and use the Air Flow Performance electric fuel pump (as supplied by Van's) can answer a couple of questions?
Has anyone mounted the pump forward of the firewall? and
Has anyone ever found any debris in the filter supplied with the pump?
I am considering not fitting this filter (as it seems rather coarse and expensive), and using an Andair firewall mounted gascolator instead. That means I will either have to fit the pump after the gascolator (forward of the firewall), or fit the pump in the Van's suggested position but with no upstream filter. Any thoughts?

Pete

Debris in filter

My AFP pump/filter is mounted in front of the spar in my RV-7. I have found debris in the filter the 4 or 5 times I've cleaned it. While there wasn't much found in there, it's enough that I don't want that crud gumming up my $500+ pump. Given the price of the pump, I would not want to have the upstream fuel supply unfiltered. Just my 2 cents!

I don't know much about the internals of the AFP high pressure boost pump. Maybe it can tolerate some amount of gunk. I'm not in the mood to find out where that threshold is. I want my high pressure pump to last at least as long as my engine's overhaul cycle.

)_( Dan
RV-7 N714D (662 hours)
http://www.rvproject.com

Agree!

Thanks for your input, Dan. Definitely agree that it's not worth taking a chance on whether the pump can tolerate debris or not.

Pete

The system needs a water trap. Install a gascolator on the firewall where you can access the drain during preflight through a 1.125" cowling hole. Installing the AFP screen filter before the electric pump is fine, but try hard to locate it in a place that is easy to access....or you won't check it on a regular basis. Better none than a filter not maintained.

BTW, the Bendix throttle body has an inlet screen, but it is lightly spring loaded. If it gets even slightly clogged it will lift off its seat and bypass a lump of garbage into the TB and spider. Don't depend on it for any gross filtering.

Dan

Why?

Needs a water trap? Why?!

A little water to a fuel injected engine (and I'm talking about a LITTLE here) ain't so bad imho.

)_( Dan
RV-7 N714D (670 hours with no gascolator)
http://www.rvproject.com

Pete,
I have same setup as DanC. I definitely wouldn't substitute gascolator for filter. I've cleaned mine several times and always find a little something each time. As for watertraps, I don't have a gascolator. I religiously sump the tanks via the drain before each flight. I have my doubts about how effective gascolators work. Read too many stories of engine stoppage due to water contamination on aircraft equipped with gascolators. Best thing is always sump the tanks, then you know.

Tobin

Agreed!

The tank is an excellent water trap.

-mike

<<Needs a water trap? Why?!>>

Sumping the tanks rarely gets ALL the water. Steel fuel system components (like line fittings) corrode and throw rust flakes into the system. Some of those components are well downstream of any filter. The one-way valves in the engine driven fuel pump are also steel; a failed valve means replacing the pump. Water tends to collect in that pump, as well as inside the throttle body. Water in the line but not yet up to the engine pump runs downhill and collects in the system low spot. Without a gascolator, the low point will likely be your electric pump assembly....you know, the $500 one.

Corrosion damage aside, yes, an engine will swallow a little water. More than a teaspoon and less than 3 or 4 ounces is gascolator territory. Without one you may get an engine stoppage, with one you probably won't notice. A gascolator won't help if you have enough water to fill the bowl, but that is why we sump the tanks. Sumping is reduce quantity. A gascolator gets the rest.

Your airplane, your choice <g>

Dan

My choice was no gascolator. No matter which end you install the extra wheel, on the ground the plane sits tail low, making the sump on the tank the lowest point of the fuel system. I thought this was reason enough, but when the 1-24 tsp range of the gascolator was mentioned I got out the calculator to see if I was still alright with the decision or if a gascolator would be justifiable.

If you religiously sump the tanks before every flight like Tobin, myself, and I?m sure thousands of other people, you would be fine even if the tanks were half full of water. Once all the water is removed via the sump, or at least enough to leave the water level below the fuel pickup, you?re only left with water in the pickup line itself. Assume a builder cut half way through the 3/8in line when making the ?screen? and there was 6in of line level enough to collect water to fill that entire cross section (ours is sloped so it would be much less than that) and what?s left is less than ? tsp.

Other than the reasoning above, I didn?t want to complicate the system and add more failure points or spend an extra $150-200 on parts that I felt weren?t needed. I?ve already got enough unnecessary junk in our plane.

Or if you?re still worried about sucking water into the engine ? don?t put water in your tanks.

To answer Pete?s original post: Our AFP filter is mounted on the first bulkhead aft of the FW and yes, you will find debris in the filter, especially in the early hours. If you do decide to go with a gascolator, you should still use a filter as well.

Good luck,

Sorry, but I have to agree, there is no real drawback to having a gascolator, and it can save your life. I'd have to go for one.

All right I'll admit it, I am a closet gascolator fan. Personally, I don't think of a gascolator as a filter function only as a water trap function, so I would use both a filter and gascolator, if I was building a plane. Having two or three inline fuel filters doesn't bother me a bit. After servicing many in my lifetime, on certified aircraft, I can never explain why I find stuff in the most down stream filter and there is stuff in that filter many times during servicing on many different aircraft applications. This seems to be a never-ending debate type thing. Some real big fans of gascolators and some real big advisaries. How about all you folks that used gascolators..have you gotten water out of them if the drainable kind? Or have you had water in them, during servicing, if just the servicable kind? If you haven't, have you ever had water in you tanks when checking them, that would indicate you might or should have seen some at the gascolator?
What about debris? Do you find debris in them, when servicing, even if you have a filter up stream? It would seem to me that if you could get some guys that have and use them, to answer those questions then you could make a more informed decision.
Water in fuel is a funny thing, sometimes it is all mixed up and presents it self a little at a time, as anyone who has spent a long time draining sumps and gascoaltors and shaking wings and redraing will know. You think you got it all, only to let things rest a bit and then you get more out everywhere. And some times you get your little bit out and that's it, there is no more to be found.
As one poster suggested water often makes it, in small emulsified bubbles, past all resources only to end up in a servo or carb reuniting all those emulsified bubbles and rotting out the inlet area of the carb or servo and causing havoc with operational issues from that corrosion breaking free. Big bucks type fixes replacing those rotted housing and big time operational issues especially with fuel injected engines.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at you own risk."

Have any of you ever had a car, tractor ,truck, motorbike, jetski or even a boat stop due to water in the fuel ?
Probably not! So why would your 50 year old pushrod chugger stop?
In ten years and 1000 hours I have never found a drop of water in any aircraft I fly. I always check though.
My 2 cents ,no gasculator.

<<Have any of you ever had a car, tractor ,truck, motorbike, jetski or even a boat stop due to water in the fuel ?>>

No, not stop, just run like crap. Less common than it once was, mostly because since the late 80's EPA/state regs don't allow fuelers to neglect their inground tank installations. I'm a car dealer. In 30 years I've fixed more than one "bad car" by having the water removed from the tank.

<<In ten years and 1000 hours I have never found a drop of water in any aircraft I fly.>>

Good for you. As for me, just last month I repaired and retrieved my friend's RV-8A (IO-360, Bendix FI, AFP pump and screen filter, no gascolator) from a distant airport. The primary symptom was injector plugging.

The cause was corrosion of the steel fuel line fittings installed firewall forward, as well as the frame of the outlet valve in the engine-driven fuel pump. Rust flakes partially plugged the fine inlet screen in the throttle body, so it bypassed and dumped a load into the guts of the TB and fuel distributor. All components required overhaul and cleaning. Note that these components are well downstream of the AFP screen filter.

My first action when I started diagnosis was to sump the tanks using an ordinary tubular fuel checker. I got no water. After finding corrosion in the system we went back and fully drained the tanks. That did net some water. We then started flushing the tanks with clean fuel, which netted a little more. A large amount? No, but....

In the course of cleaning and checking fuel lines, I disconnected the fitting at the inlet of the engine-driven pump, pulled the hose down below the bottom of the firewall, and directed it into a clean white bucket. When my helper flipped the AFP pump switch, I got a nice blob of water. As I mentioned previously, with no gascolator the lowest point in the system is the section between the fuel selector and where the line angles up to the ED pump firewall forward. That section includes your expensive AFP pump.

The aircraft now has a pressure gascolator at the base of the firewall. I flew it to Reklaw a few weeks ago, and lo, I got one more little blob when I sumped the gascolator during preflight on Sunday morning. It had a slight rusty tinge, so it was probably hiding somewhere near steel, not in the tanks.

This aircraft is normally hangared when at home, with full tanks. Last spring it sat outside at a paint shop for a few weeks, and someone stole most of the fuel. I assume this was the period during which the tanks accumulated some water. I judge the degree of corrosion found in the line fittings to be excessive, more than I've seen before, so maybe some other agent was introduced during the fuel theft. No way to know. Even if it were true, it does not change the dynamics of water retention and removal in this system.

Bottom line, based on observation specific to the RV-8A: One, the tanks retain some water. There is no cup-style sump, so you rarely get it all. Two, water will hide/collect in the low spots in lines and components. Three, it does cause corrosion. Four, it may be the corrosion that ends your flight, not the water itself. Five, a gascolator would have caught water before it got to the steel firewall forward components, caught any rust generated within the system between the screen filter and the firewall, and would not have allowed water to drain back from the firewall forward uphill stretch to the area of the AFP pump.

Confession time: While under construction, my friend and I debated the merits of installing a gascolator. We decided "no", for the reasons mentioned in other posts here as well as my friend's intent to keep the aircraft hangared. Put another way, until the above events taught me otherwise I was uncommitted about gascolators. Not anymore.

Dan

Back in early 2004 when I was finishing up my IO RV-7A, I called AFP to ask them if I should install a gascolator. It was interesting that they said a gascolator was not necessary. Their reasoning was that the low point in the fuel system was the fuel tank drain plugs and that any water in the system would collect there...

Paul

rv72004 said:

Have any of you ever had a car, tractor ,truck, motorbike, jetski or even a boat stop due to water in the fuel ?
Probably not! So why would your 50 year old pushrod chugger stop?
In ten years and 1000 hours I have never found a drop of water in any aircraft I fly. I always check though.
My 2 cents ,no gasculator.

Click to expand...

But what do you have to lose by putting it in? That is the pressing question that I can't answer. I've drained a crapload of water out of airplanes in my 4+ years and 380 hrs, and I live in LA. Not that any of these airplanes are hangered either. The most we got out of any one airplane was our C177 just after we bought it, it had been sitting for 6 months and had almost 2 gallons of water! Even after competely draining the system and filling with fresh fuel, and trying to purge the system, we still had a couple of burbles when on upwind on the first flight.

I've gotten a couple of ounces out of other airplanes at various times. I don't see why something that could save your life is received with such hostility in the homebuilding circles. There is a reason that it is required on certified aircraft!

No hostility, it was just my opinion/experience that a gasculator is not really needed.
However after reading DanH recount of what can happen I am considering going to the extra hassle of mounting a gasculator.

For those of you with the the filter and gasculator on 7s where did the gasculator mount ?

This discussion has rumbled on a little longer than I thought! I have an Andair gascolator on my RV-6A mounted on the LHS of the firewall using the Andair mount. After reading all of your posts I think I am inclined to retain a gascolator on the new airplane and fit the electric pump on the firewall after the gascolator. The Andair gascolators are cheaper than the AFP filter, easier to service, have a finer filter and possibly better made. I don't really understand why everyone is so keen to mount the electric pump in the cabin?

Pete

Water in gasoline

Are there any products that you can put into your gasoline to try to get any "hidden" quantities of water to mix back up with the gasoline and get burned?

Would running a bit of mogas that has ethanol work?

Perhaps just putting a bit of ethanol in the tank from time to time...

penguin said:

I don't really understand why everyone is so keen to mount the electric pump in the cabin?

Pete

Click to expand...

I strive to keep as few fuel fittings as possible in my system and to keep them out of the harsh environment forward of the firewall. A mistake up there with a leak, break, rupture, etc. is a bad day waiting to happen.

With a AFP filter, a gascolator is just more fittings, more complexity for no real value. Is your airplane going to be parked outside in the weather? If yes, then maybe a gascolator is marginally of value if you abuse the o-rings on the fuel caps. In 3 years of flying my RV-6, I never found one drop of foreign material in the gascolator. My Rocket has the AFP unit and that's all.

That said, it's your airplane so build it the way you want it.

Fuel leaks

f1rocket said:

I strive to keep as few fuel fittings as possible in my system and to keep them out of the harsh environment forward of the firewall. A mistake up there with a leak, break, rupture, etc. is a bad day waiting to happen.

Click to expand...

On top of that, the slightest leak in the cabin will be very easy to detect with your mk. 1 calibrated nose, whereas if the leak is in front of the firewall, it might go unnoticed until it ignites.

FWIW, most carburated certified airplanes keep the electric pump on the firewall, while most FI ones have it aft of the firewall. I have NO idea why this is however.

To add to the confusion, A Pitts S-2E I flew occasionally had the electric pump forward of the firewall, Extra 300s have the pump forward of the firewall, but Cessna 172 XPs (Cont IO-360) have the pump aft of the firewall (under the floor boards).

Pete

This went on for quite a while and I don't intend to keep it going but a question went unanswered. The reason the pump is mounted aft of the firewall is to keep it away from heat, possibly adding to the liklihood of vapor lock. They suggest putting it in a housing with outside air directed to it if you mount it on the front of the firewall - (sounds to me like a lot more trouble. ) This is stated in the paperwork that comes with the pump. I just read it tonight in between cussing at the fuel lines I was trying to bend to work with it.

Charlie Kuss has some info here

Gents,
I was having problems on my 6A with the pump burning up. The pump would get noisier and Noisier and eventually get to the point where it would not start up and need replacing. I had to run my pump nearly all the time as I had vapor lock above ~7k'.

While out west last Year CHarlie Kuss helpped me with buying a replacement pump at my local NAPA and recommended I replace the AFP filter with a lower micron Filter which was a direct replacement filter for the housing AFP provides.

I went to a Carter P500o Pump which looses the plastic housing found on their stock unit.

And I went to the 25 micron filter 4ila part number with Viton Seals. Its Wayyy chaeper than the one AFP sells and provides much better protection to the pump. After putting in the 25 micron filter I never lost another pump in the 6. I put this pump and filter assy in my 8 and saved hundreds off the AFP stuff and got better protection, serviceable from the field. I believe the AFP unit is a 6ila filter. Also the AFP filters come with Nitrile seals which wont hold up under Auto fuels. Viton seas will.

Charlie Kuss was my resident buzzhead on this and I hope he chimes in. Bob Jupundza(sp) also is up to speed on going with racing type as direct replacement to increase quality, lower cost, and improve serviceability on the road.
Here is the Filter to buy and have AFP keep theirs.

Im sure the RV-list has some good info here..... OK I just went and looked. Its message number 131787

Enjoy

Filter & seals only?

Mike,

Are you indicating to buy the filter element and the two seals and they install into the existing AFP filter housing?

Thanks,
Andy

From my friend Charlie:
You can buy replacement filter elements for both the stock 6ILA
filter sold by Vans (single filter for the whole system and therefore
a single point of failure) or the slightly smaller 4ILA units. A
group of local RV builders made a group purchase of the 4ILA filters
through Pegasus Automotive Racing Parts (RV-9A builder Chris Heitman
owner). We've installed one filter in each wing root area. This
allows easier servicing of the filter, eliminates 2 fittings inside
the cockpit and eliminates the single point of failure.
The stock filter is approximately 147 microns (about .006"). We
opted to get our filters with 25 micron (.001") screens and Viton
rubber O-rings. The stock Vans filters come with Nitrile O-rings.
Nitrile doesn't do well in the presence of unleaded (auto) fuels.
Viton works well with all fuels, even ethenol. You can buy the Viton
O-rings and screens in a variety of sizes as fine as 25 microns from
Flow Ezy or any of their distributors. See web links below for more
info.

http://flowezy.freeyellow.com/racingMODEL_4ILA.html

Flow Ezy's web site sucks! To find the info on the 6ILA filter, go to
the page below. Scroll down to the 8th item, marked High Pressure
In-Line Filters and click on the GET TECH INFORMATION link. Flow Ezy
is the actual manufacturer of these filters. Airflow Performance and
Vans both use these filters on their systems.

http://flowezy.freeyellow.com/flowezypagehydraulicfilters.html#HIGHPRESSUREIN-LINEFILTER

FYI, Chris gave us a really good deal on a group buy of 10 filters.
We paid about $52 each. See

http://www.pegasusautoracing.com/productdetails.asp?RecId=3469

Charlie

Filter setup picture

Kahuna (& Others)

The setup you have described is what I've been looking for. I have wanted to have an in-line filter before the selector valve. My focus has been trying to figure how to get a filter somewhere between the gearleg weldment of my 7A and the selector, as I thought that this would be a logical place (don't ask me why). However there isn't room between the cover support ribs to fit a filter into.
After reading your post above and a similar post from you and Charlie Kuss on the Matronics site, it looks like you have a workable solution with the wing root installation and the 4ILA filter.
Now I'm trying to visualize the plumbing for my plane. I don't have the flop tube, so my fuel line is a straight shot from fuse to fuel tank fitting.

DO YOU OR SOMEONE HAVE A PICTURE OF THE WING ROOT SETUP?
My 7A will have a 0-360 Mattituck

Thanks for your help and discussion on this topic.

Sam