Matt's RV-7 Project

Believe it or not, it took me an entire afternoon to install the hose that goes between the engine-driven fuel pump on the back of the engine and the fuel injection servo up front. This seemingly simple task was greatly complicated by clearance problems and lack of space to work in (is this starting to sound familiar?). You want the fuel line to be far away from the hot exhaust pipes, but the ideal routing – up over the "wing" of the oil sump – is blocked by the mixture bellcrank. So, I had to play with various routings of the hose until I could find a way to get it as far away from the exhaust as I could, while still staying clear of the mixture linkage when it's in the idle cutoff (worst case) position.

Since the hose is right there, I put some additional heat shields on the exhaust pipes to keep the fuel line cool. In this photo you can see the somewhat circuitous routing the hose takes, as it exits the fuel pump, crosses under an engine mount tube (the photo doesn't show it, but there's an inch of clearance there) and then climbs up away from the exhaust pipes. A pair of back-to-back adel clamps, shown here partially obscured by the exhaust, secures the hose to the #4 intake tube. I ended up with at least an inch of clearance between the heat shields and the hose. By the way, all my fuel/oil hoses are Stratoflex 124J assemblies with integrated firesleeve, made to my specifications by Precision Hose in Tulsa. Good customer service and good prices too.

These clamps were a giant pain to install, because the normal bolt-flinging properties of the adel clamps were magnified by the almost complete lack of access to the area where I wanted to put them. I managed to scrape a bunch of paint off the #2 and #4 intake tubes, but it's all cosmetic stuff.

I need to do better than one hose per day if I'm ever going to finish this thing.

Matittuck included a hose to go from the mechanical fuel pump on the back of the engine up to the fuel injection servo on the front. Here I'm test fitting it to the fuel pump outlet, and I've clamped it to the #4 cylinder's intake tube with adel clamps to keep it away from the exhaust:

The clearance between the hose and the #3 exhaust pipe is not much more than an inch, but there doesn't seem to be anywhere else for the hose to go – the mixture bellcrank gets in the way.

The included hose is too long by a couple inches (it's supposed to attach to the silver inlet port in the middle of the photo). I'll have to have a shorter one made up.

I bought some cheap plastic tubing from the hardware store and used it to measure for the other hoses I'll need to have made, without expensive guessing. Here's what the hose between the firewall and fuel pump inlet will look like:

Only somewhat visible here is the mockup of how the oil pressure hose will go:

Here's the stand-in for the manifold pressure hose:

I ended up with templates and measurements for five different hoses (I forgot to take a picture of the faux fuel pressure hose).

While I was messing around with the fuel servo, I replaced the nyloc nut on the mixture shaft with an all-metal locknut:

There's a bolt at either end of the alternator tension arm, both of which need to be safetied. Some folks use one long length of safety wire between the two bolts, but that seems like it would be a pain when the belt inevitably wears out (since you need to loosen the bottom bolt to replace the belt). I also didn't want to just loop safety wire around the arm itself, since it would eventually vibrate and dig a groove into the steel.

So, I came up with what I think is a clever way of safetying the two bolts… first I drilled a pair of #30 holes in the meaty part of the arm:

Then I grabbed some #4 steel tinnerman washers and 1/8" steel pop rivets:

When riveted to the arm, the washer sits up above the surface just the right height to capture a loop of safety wire. The wire then bears on the steel pop rivet stem instead of wearing a groove in the arm.

With the ring gear removed, it's pretty easy to safety the upper bolt.

After putting on the belt and adjusting the tension, the lower bolt gets torqued and safetied in the same manner:

For future reference, the belt that seems to fit the best is a Gates 7360:

I tried a 7355 and it did fit, but it was very tough to install. I'll use the slightly longer belt unless I end up having clearance problems between the alternator and cowl.

The B&C 60-amp alternator comes with all the hardware you need to mount it to the engine. I first bolted the (very substantial) mounting bracket to the matching boss on the engine:

The two mounting bolts get secured with safety wire, and you also bend up the tabs on the little washer-plate thingy to further immobilize them. Talk about belt and suspenders.

The included spacers put the alternator in just the right position to get the pulleys lined up. Here it's just hanging from the pivot bolt, as the tension arm isn't in place yet.

The alternator came with a Gates 7365 belt:

Oh boy, another little surprise… not only will I have to take the propeller off to replace the belt at some point in the future – probably a most inopportune time – but I also had to pull the ring gear to get the belt past the starter's pinion gear.

Here it is with the tension arm loosely connected. I think I'm going to go find a shorter belt so I can tuck the alternator in closer to the engine and farther away from the cowl.

I also had to replace the belt in our vacuum cleaner yesterday, so this has pretty much been an all-belt weekend.