Fuel Pump/Firewall Interference

Hi all,
On my RV-4, (0-360) even though I bought the special fuel pump overflow fitting that Van's sells, I still only have about 1/8" - 1/4" clearance between the fitting and the firewall.
I have heard there is a smaller fuel pump available, but I don't know the part number.
I've also been told to put a dimple in the firewall, but that is where the angles that support the rudder pedals go, and they are heavy angles.

What have some of you done about this issue?

Its very tight. My engine (O-320) came from Aerosport Power and they tapped in an extra fitting. You can just see it in this picture. They had had customers with problems in the past. You could do the same.

I have never had a problem with the pump meeting the firewall, but then I think I have a little more space in view of this mod..

I made a small cutout in the leading edge of the footwell to give tghe fuel pump a little more clearance. It's about 1" back from the top bend and about 1 1/2" wide as I remember. It's a pain, but it works.

More Room

RV4, 0-360, CS prop with McCauley governor

I went at this problem a bit differently....I unmounted the pump, disassembled it and ground off at least 1/8" of the mounting stud. I dressed it, reassembled and remounted the pump. Took probably an hour. I attached a picture and although it looks really close the picture is distorted. There's more room than it shows. Was it worth the effort??? I didn't think there was an option (still don't).

[/URL][/IMG]

Good Luck!

anyone know if you still have this clearance problem if you have a conical mount

If conical means dynafocal II, the answer is yes. Link to my pictures in my post below

conical mount is not Dynafocal ll

Conical answer

I do have a conical mount O-360 C2A and the clearance is about the same shown in the other pictures. Off the top of my head I'd say I have about 1/4 inch of clearance between the firewall and the overflow part and I can check tonight for the exact amount if you'd like.

It's been awhile, but I think I had to remove my fuel pump, install the piece and then reinstall the fuel pump. A few four letter words were involved as well.

Rick

Me too

I have that exact problem. I wouldn't have thought anything less that 3/4 inch clearance would be safe when the motor is kicking around during startup. Is it possible to rotate the mounting plate so as the outlet is oriented in another direction?

Is it possible to remove the fuel pump without pulling the motor off the mounts ? ie how far backwards does it need to go to clear the engine block ?

What purpose does it serve? I assume it is there to stop fuel leaking into the sump if the diaphragm leaks ?

My 180 RV4 had about 1/4 inch clearence and I just flew as is. I had dyna focal mounts. that RV4 N112TT has 1358 hours on it with no visable sign of making contact. I just bought a 180 RV4 with 245 hours on the air frame.It has Vans brass /copper fitting about the same distance. It has Conical mounts, here again, there is no sighs of contact. Some aircraft company,s do not put an over flow on the fuel pump.

fuel pump overflow clearance

On my 4 the Vans right angle overflow fitting was touching the firewall. This has been a while back but as I remember, I talked to someone at ECI and they recommended the following: Remove the fuel pump and remove Vans fitting. You will later install a plug that has an internal hex fitting so that the plug is totally within the fuel pump. Then cut the copper tube off of the Vans fitting and save. Position the pump as it would be on the engine and drill a hole in the bottom of the overflow port. This hole will need to be positioned inwards toward the body of pump so as not to be blocked by the new plug. The hole should a diameter such that you get a nice tight fit with the copper tube from Vans fitting. Use JB weld to bond the copper fitting into the hole you drilled. Flush pump to eliminate metal shavings, reattach to engine you now have clearance. Seemed a little bizarre drilling a hole in a perfectly good pump but it is working fine on my 4. Even with doing this procedure my pump is within a 1/4 inch of the firewall and I have had no rub issues with it. Note: you attached your post to old thread and to get to your question one must diligently go to the "Last" page. Maybe you would get more input with a new post so you are at the top. my 2 cents

The concensus seems to be.

It looks as though 1/4 inch strong clearance is enough. That being the case I could probably hit the firewall with an angle grinder and gain that clearance without causing damage to the underlying brackets.