Saturday, February 13, 2010

One thing. Then another

I wrote a few days ago about my reluctance to take on any particular task because the things I do seem to conflict with things I need to do later. But, thanks to the wise advice of some RV-building friends, I decided to press on by making arrangements for the fuel line to pass through the firewall to the engine.

This is something I should have done before I put the engine on, but it's not a deal breaker. What is a pain in the neck is that the instructions from Van's don't look at the "big picture" when telling you what to do.

Here's an example: When you first get your firewall, you're told to add doubler plate for a fuel pump. This assumes, however, that you're going to put a carbureted engine on the beast. But I decided, later, I'd have fuel injection. The little fuel pump isn't needed because a high pressure pump is installed upstream. But there you are with a doubler plate and two nutplates.

Later, when you put the battery contactor on, it calls for rivets to be drilled out in some firewall angle, and holes drilled for nutplates to attach the contactor to the engine side of the firewall. Fine, no problem, right?

Wrong. Because when you get around to putting your doubler plate on to strengthen the pass-through for the fuel line, you find that one of those holes you used to attach the nutplate for the battery contactor, is also used to locate the doubler for the fuel line pass-through. How many times can one person drill out rivets?

So I decided to move the doubler plate to the left, ignoring the attachment to the firewall angle.

This did not cause a problem until I realized that the distance between the doubler for the fuel line, and the doubler for the fuel pump I'm not using, leaves me no room to drill a hole for the throttle cable. (You can see on the fuel pump doubler that I "scalloped" out room for a hole for the throttle cable, but the hole for the spiffy SafeAir "eyeballs" needs to be 3/4" and there's a one inch nut that holds it in place. That isn't going to work here.

I could move the throttle cable hole further to the center, but now it'd be in danger of hitting the engine mount and I just saw images on Van's Air Force this week of what can happen over time doing that.

What I could do is slice an angle off the bottom of the fuel line doubler, ignore one of the rivet holes I've already drilled, and drill another.

The other option is just to locate the pass-through for the throttle cable through the doubler that was originally installed for the fuel pump.

It doesn't much matter for now; I don't have any help to hold a bucking bar in place as a backrivet plate to rivet the thing on.

Update 3:17 p.m. - I ended up scalloping the fuel line doubler to allow room for the throttle cable passthrough.

And installed the bulkhead connection. You can see I also drilled the hole for the throttle cable passthrough, which will be the Avery one-hole swivel. The problem? The instructions seem to say I should drill a 3/4" hole for it. So I bought a nice, pricey, 3/4" Greenlee punch. It worked great. The hole's too small. Anyone know what size it should be?

Here's a problem. I grabbed the VA-138 hose I ordered a few months ago just to see how it fit. It seems much too long, which shouldn't be the case since I only moved the fuel line passthrough over by about 1/2". Will have to figure this out later.

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