Will I need a fuel filter drain on firewall

[ron sterba]

Rv9A. IO-320 Everything is wired and complete firewall forward. Have Andair electric pump and filter installed just below Andair selector valve. My ONLY place to drain fuel from the fuel system is under the tanks. I'm so use to draining the C-172 tanks and carb drain that I was wondering should I install the fuel/filter drain or a gascolator (2013-14 Page 12 Vans catalog) on the firewall? Again my engine is injected. Seems it would be awkward to clean a filter thats in the cockpit or does it even matter?

Ron in Oregon

[spark68]

Ron,

I'm putting a similar set up in an RV-6 I'm building. IO-320 and Andair pump/filter. My research indicates that no gascolator or filter forward of the firewall is best. Heat soak of the fuel is a problem, and injected engines don't have a float bowl to fill up with water like a carburetor. The water just goes through the injectors. I am however planning on pre-filters in the wing roots. Andair makes a nice one (GAS375) that can be drained. They would act as a pre-filter before the fuel pump.

spark68

[bobnoffs]

please someone explain the difference between a big slug of water in the bottom of a float bowl or a big slug in the bottom of a fuel tank.thanks

[Sam Buchanan]

Originally Posted by ron sterba

Rv9A. IO-320 Everything is wired and complete firewall forward. Have Andair electric pump and filter installed just below Andair selector valve. My ONLY place to drain fuel from the fuel system is under the tanks. I'm so use to draining the C-172 tanks and carb drain that I was wondering should I install the fuel/filter drain or a gascolator (2013-14 Page 12 Vans catalog) on the firewall? Again my engine is injected. Seems it would be awkward to clean a filter thats in the cockpit or does it even matter?

Ron in Oregon

Originally Posted by bobnoffs

please someone explain the difference between a big slug of water in the bottom of a float bowl or a big slug in the bottom of a fuel tank.thanks

Ron has drains on the tanks but his injected engine has no float bowl.

[brad walton]

I think that is the point being made. The lowest point in the system is the fuel tank drain. No need for other sumps. Cessna and other similar have more than one low points in the system and need drains at each low point.

[pierre smith]

Originally Posted by spark68

Ron,

. Heat soak of the fuel is a problem, and injected engines don't have a float bowl to fill up with water like a carburetor. The water just goes through the injectors.
spark68

Not quite true. Enough water will stop the engine. We totaled a fuel injected Cessna Agwagon as a result of water-contaminated fuel....yeah, water will go through the injectors but then combustion ceases, no?

Best,

[fixnflyguy]

If you choose a gascolator (I have one on my-4) and it stays stone cold even between the pipes, make sure it has an accessable drain, and use it. We witnessed a nearly disasterous Lancair deadstick landing that totaled the aircraft because it was built with a gascolator that had no access with cowl installed. There was 8 oz of water in it when we pulled it apart, although he had just sumped wings,and done full run-up, and even flown the day before. The engine quit during climb out/departure turn.

[Sig600]

The reason you get water 99% of the time is condensation. It's why you fill the tanks if the airplane is sitting, to minimize that void and reduce ability for condensation to collect. A fuel injected system has no void beyond the tanks for air/moisture to collect so no I would not, and don't have a gascolator.

If somehow a small amount of water is able to collect in the lines, you would have pulled it through the engine between start up, taxi, run up. Water in the tanks is the threat.

As far as the gascolator above the exhaust pipes, I would be more worried about it developing a leak right onto the hot exhaust. Drains have little rubber o-rings that can wear, fold over, or get debris stuck under them preventing a good seal.

[Bevan]

Originally Posted by spark68

Ron,

I'm putting a similar set up in an RV-6 I'm building. IO-320 and Andair pump/filter. My research indicates that no gascolator or filter forward of the firewall is best. Heat soak of the fuel is a problem, and injected engines don't have a float bowl to fill up with water like a carburetor. The water just goes through the injectors. I am however planning on pre-filters in the wing roots. Andair makes a nice one (GAS375) that can be drained. They would act as a pre-filter before the fuel pump.

spark68

At least one fuel injection manufacturer requires a fuel filter either immediately before or after the mechanical fuel pump. That could be FWF on a RV.

Bevan

[bkthomps]

Originally Posted by bobnoffs

please someone explain the difference between a big slug of water in the bottom of a float bowl or a big slug in the bottom of a fuel tank.thanks

one is more problematic when it ices up on/around takeoff