O-320-H2AD fuel line routing

[rjcthree]

Those (poor sods) who've done an H2 install, if you used the standard fuel pump, did you route the output of the engine driven fuel pump back over the cylinders down the backside of the engine down to the carb, or did you drop straight down and work around the crossing exhaust pipes?

My plan was to go back over the top, but it's a solid 4' of a run, and it's getting crowded back there. Going straight down, through the baffle, past the crossover exh pipes, while having to go past the exhaust, is only about an 18" run. I need to decide, it's the only plumbing left.

Rick 90432

[Lionclaw]

Hi Rick!

Glad to hear your install is coming along. I went the same route as Graham and a few other guys with the fuel lines.

Here's some pictures from ~1 year ago. I've had it out to the run up pad a few times, and so far there hasn't been any problems with this routing. The plane hasn't flown yet, but it is ready to fly. I just need to do my W&B and inspection.

Here you can see the routing from the fuel pump back through the baffles. The line that goes under the pump has a 90deg fitting. The baffle brace does a good job holding the adels. I added a doubler on the baffle in the back where the grommets are installed. I've since put a glob of silicone between the 90deg fitting on the fuel pump and the front baffle to keep it from rubbing.



Behind the baffles, the lines duck under the engine mount cross brace. They hug the engine and attach to the vacuum mount pad. The tee below has a restrictor fitting for fuel pressure. After that it attaches to a sump bolt before heading down to the carb.

[Alschief]

I went over the top and down.


AL

[rjcthree]

Thanks Andy and Al. I think in going to go under on this one, using the ellisons front inlet. I'll heavily shield the exhaust in that area.

I've also decided to rearrange some lines, but it's notnhelping my congestion behind the engine enough to make me want to run another -6 fire sleeved line through there. The big fw mounted oil cooler and -8 hoses make for a big obstacle.

Rick 90432

[Walt]

The gascolator/fuel line/FF xmtr make for great heat sinks, which in this case is NOT a good thing. I would recommend a shroud with a cooling tube or some serious firesleeve to cover it all. With the added height of the fuel pump you've set up the perfect scenario for vapor lock.

[rjcthree]

Walt, that's why I'm going straight down to the tb, to cut out somewhere around three feet of fuel hose run. If its a problem, it will show quickly. My setup has a blast tube for the collator. Rick

[Walt]

The problem will be on the way up to the fuel pump

[Lionclaw]

I've put a few hours of ground run time on my setup without any issues so far. I haven't heard of any issues from other H2AD guys.

A few years ago I stopped and talked with one of the kit engine builders at their tent at Oshkosh. His opinion was that this engine was less susceptible to VL because the fuel pump sits right in the path of the incoming cool air.

Is your concern that a heat soaked engine on the ground might get VL and be hard to start? It would seem like the boost pump would deal with that.

[rjcthree]

The pics Andy posted shows the most common H2 routing for carbs, hands down. The is some successful history there.

Since I have an Ellison, there are other considerations.

Thanks everybody for your thoughts.

Rick 90432