N

nauga

Well Known Member
I've got a Vetterman crossover exhaust on a standard-sump O-320-D2C (carburated) and the gascolator mounted between the gear at the bottom of the firewall, and I was chasing low fuel pressure indications from first flight on. The gascolator is pretty close to the aft crossover, and if I bypass the gascolator I get a 1-2 psi increase in fuel pressure (boost pump off). I'm thinking that the heat from the aft crossover (among other things) on the gascolator is causing the low pressure. Soooo....I figure I've got 4 options, in order of preference:
1) Figure a safe way to mount the gascolator with the crossover exhaust
2) Leave the crossover and completely remove the gascolator
3) Replace the crossover with a 4-pipe and reinstall the gascolator
4) Leave it as it is (not my favorite, but hey...)

Any suggestions?

Thanks,

Nauga,
whose RV-4 is awakening from hibernation
 
Dave,

Good seeing you back!

I'd consider:

1) A blast tube to cool off the bowl, which seems to act like a big 'ol heat sink.

2) As suggested, a heat shield. You should be able to make one fit if you have > 3/4" clearance.

3) Delete the gascolator. I've never found anything but fuel in mine and see it as a potential failure point...
 
Kyle Boatright said:
Dave,

Good seeing you back!

I'd consider:

1) A blast tube to cool off the bowl, which seems to act like a big 'ol heat sink.

2) As suggested, a heat shield. You should be able to make one fit if you have > 3/4" clearance.

3) Delete the gascolator. I've never found anything but fuel in mine and see it as a potential failure point...
Click to expand...

Wow, Kyle and Gil are still around :D
I will probably try a blast tube if I can't find a better location for the gascolator. I've had a heat shield on it from first flight on. 3/4" clearance?! The bowl is about 10" from the aft crossover (from memory) and that just seems too close.

Nauga
 
Where is the heatshield

nauga said:
Wow, Kyle and Gil are still around :D
I will probably try a blast tube if I can't find a better location for the gascolator. I've had a heat shield on it from first flight on. 3/4" clearance?! The bowl is about 10" from the aft crossover (from memory) and that just seems too close.

Nauga
Click to expand...

Yep... still around.... with a RV-6A awakening from hibernation....:)

Is the heat shield on the gascolator or the crossover pipe. The latter should be better...

gil in Tucson .... but was probably in LA when you read previous stuff... :rolleyes:
 
Nauga,

FWIW, I bought an Andair gascolator from Aircraft Spruce, and about pulled the rest of my hair out trying to figure out how to mount the #$&* thing! I have a conical O-360 mount, so maybe it's not normallly so difficult for others.

After calling Van's for advice, Bruce (I think it was Bruce at least) said he wouldn't even use a gascolator - instead, he uses in-line fuel filters - one between each wing and the fuel selector. I mounted mine between my feet (next to the battery) - after the boost pump but before going through the firewall. He also said that is now the STANDARD setup for the RV-8 - an inline filter as opposed to a gascolator. Hopefully this way I'll have no fuel sitting on the firewall side getting hot - it will all be firesleeved.

Like others have said, it won't do you much good unless it is sitting in the low point of the fuel system, and in the "4" that's hard to do.

Cheers,

Rick
 
exhaust shield and gascolator

nauga said:
I've got a Vetterman crossover exhaust on a standard-sump O-320-D2C (carburated) and the gascolator mounted between the gear at the bottom of the firewall, and I was chasing low fuel pressure indications from first flight on. The gascolator is pretty close to the aft crossover, and if I bypass the gascolator I get a 1-2 psi increase in fuel pressure (boost pump off). I'm thinking that the heat from the aft crossover (among other things) on the gascolator is causing the low pressure. Soooo....I figure I've got 4 options, in order of preference:
1) Figure a safe way to mount the gascolator with the crossover exhaust
2) Leave the crossover and completely remove the gascolator
3) Replace the crossover with a 4-pipe and reinstall the gascolator
4) Leave it as it is (not my favorite, but hey...)
Click to expand...

Nauga....As you can see in the picture I make a little shroud (aluminum and is split with leftover hinge pieces) for the gascolator (which is removable) with intention of running cooling air to it if needed (didn't have to) and I also made a shroud for the exhaust.....With this setup I have never had a problem......taking ot out of the fuel system is not an option for us in Canada.

 
http://www.aircraftspruce.com/catalog/appages/flowezyfilter.php

This is the one I used. It gets pretty lengthy by the time you add the hardware. For most setups (if you are using the standard 3/8" aluminum fuel lines) you'll need to get two AN912-2D reducer bushings to go into the filter, and two AN816-6D nipple fittings to connect your fuel lines (at about $2 each). Total cost for me was about $95. That's a lot but my Andair Gascolator was $170 so I won't complain.

Hope this helps . . .
 
Marc DeGirolamo said:
With this setup I have never had a problem
Click to expand...
Dang, that's even closer than mine! Mine is mounted on the lower crossbar. Maybe it's time to reassess the hookup and shielding. The less I have to change the better.

Nauga,
stripping for interior painting
 
Use an Andair as a filter?

Nauga - I am still building but went round and round on this a while ago. I did not want the gascolator where you have it, for the reasons you have come up with.

For better / worse I decided to install an Andair gascolator, but for its filtering properties - 70 micron - just behind the fuel valve. The reason I went this route was because once you think of it as a filter only, it appears altogether easier to disassemble for inspection. I will not normally operate its drain, although you could easily extend its drain and locate that remotely. It mounts on the rear of the two brackets on the LHS in this picture.
 
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