More MD-RA Gascolator chat :)

Hello my fellow Canadians,

I am working on the FWF section of my -7 build. I didn't get the gascolator or bracket in the FWF kit from Van's. I do have an Andair's Gascolator to use that came with the kit from the previous builder.

So now what. I feel like just mounting it on the firewall where it is suppose to be and not deviate from the plans. But what's the consensus on Vapor Lock due to the gascolator being in a hot cowl ?

I will say this. My Sonex did exhibit some Vapor Lock symptoms and the engine would "buck" on the odd occasion when the ambient temp was hot.

I installed a duct to duct outside air right on to the Gascolator. Seems to have solved he problem. Winter came also, so the ambient air dropped.

Advice and suggestions ?

Thanks,

Darren

mdra

Been there done that. I really felt strongly about wanting the gascolators in the wings roots, made the most sense...and mdra would be happy. All the figuring showed that it was easier to have two (less plumbing with one each side), and we tried and tried to do the plumbing set up. The 9 has less space to jam in the bends outboard of the fues. So...we surrendered and put the andair fw fwd and will just live with it. I dont believe vapour lock will be an issue as a pile of Canucks have it like this with no reported problems, but...will get back to you on that.

I have seen a few 7 and 8s that jammed the gascolators on the wings and it looked good and made sense...but just not possible on the 9s without adding a lot of silly tight bends. There were some old threads here where people provided me pics.

Others have mounted the gascolators in the cockpit...that doesnt seem like a plan I like. But...1st build so live and learn.

Hey Rick,

Thanks for the reply. I'm lost on something else. Maybe you can help.

I have the Andairs Gascolator, not the Van's one. Best I can understand things. The Van's drawing shows the fuel tube leaving the fuel selector valve then running to a fuel pump on the cabin side of the firewall, then a tube with an elbow running down and punching through the firewall. From there the gascolator connects and then to the engine.

The Andair's Gascolator has a fuel in and a fuel out, but the way the literature shows the mounting I think the fuel coming from the the fuel pump should be on the engine side of the firewall, not the cabin side of the firewall.

If that makes any sense.

What did you do ? I don't get my engine till Feb. It is a IO-360 parallel valve 180 hp. I don't know if the fuel pump is mounted on the engine or remotely mounted.

Dumb @ss question I'm sure, but I can't visualize what I'm to do.

Thanks,

Darren

fuel runs

No dumb questions, we have all been there and asked questions them.
The fuel comes in from both side tanks into the andair fuel selector...then goes forward and between pilot copilot legs is the afp BOOST pump, then it runs along the tunnel towards the front, makes a right turn goes to the pass side and exists throught the firewall into the gascolator. From there it heads to the mechancial fuel pump on the engine, then down to throttle body on the engine. NOTE if you use an afp fi, you need a fuel return line. If you use silverhawk, no fuel return line. You said you are going FI so....no little facet fuel pump on the inside of the firewall, just the big boost pump inside.
PM me if you want and happy to chat or send some pics. You should find a local builder and peak at the install to wrap your head around how it goes.

Check with your engine supplier if return fuel line is used in your fuel injection, not all systems require it.
Trial install engine mount, determine where fuel line penetration clears engine mount and doesn't interfere with control cable penetrations per plans. You'll need an AN833 90 degree bulkhead fitting if you don't already have. Map out 3/8 tubing routing around engine mount to gascolator location. Fabricate mounting bracket out of leftover 2X2.5X.25 angle or similar angle so gascolator clears engine mount and drain valve clears lower cowling. You will probably have to install the gascolator backwards (Andair nameplate facing toward firewall). Very important to install a doubler plate behind firewall, so gascolator mount has NO FLEX. You may need an AN822 fitting exiting the gascolator, determine later when you are fitting the fuel flex hose to the fuel pump. Install fire sleeve & heat sleeve as required to minimize vapor lock problems. You could also run a air blast tube down to the gascolator later.

NOTE if you use an afp fi, you need a fuel return line. If you use silverhawk, no fuel return line.

Click to expand...

Although the supplier reccomends the return line, I have installed a number of them with out the optional return line. I do not like to install the additional cable, valve and return fuel lines without a definite reason. In my experience, which included hundreds of flight hours, over multiple years, I see no reason to have this additional complexity. Hot starts are not a problem and the engine shuts down quite nicely using the idle cutt off.

Vans Gascolator Installation Issues

Guys,

I'm right in the middle of these issues. I don't mean to hijack the thread, but I have some related questions:

1. Gascolator design fuel pressure. I want to install my Vans GAS-5 on the lower-right front of the firewall on my IO-320 RV-6. That would put the gascolator on the outlet side of the fuel pump. Don at Airflow Performance tells me that it would need to accommodate 40 psi. What is the maximum design operating pressure for this unit? Are there any concerns about flying with the gascolator pressurized to boost pump pressure?

2. Installation Rigidity. I understand that the gascolator needs to be backed up by a firewall doubler for rigidity. Has anyone posted a simple design for the doubler?

3. Gascolator Cooling. I appreciate the comments that I have read elsewhere about how a firewall-mounted gascolator is a big heat sink that promotes vapour lock. I'm keen to install a blast tube for cooling. Problem: I mounted my battery on the forward side of the firewall, RV-7 style. That leaves a tight space for the gascolator beneath the battery box. Don't people typically run a blast tube into a shroud/box? Can anyone shed light on what this would look like over a gascolator?

Thoughts?

Rob
Ottawa

gascolator doubler

Rob,
have a look at drawing OP-28.
It shows a gascolator doubler that ties in to two of the angles on the firewall.
Should give you an idea how to fabricate something that will give the required rigidity.
The Van's part number is VA-161. I happen to have one in hand. You are welcome to have the one I have, either to see if it fits, or to use it. It would not hold me up to wait for another one.
Bill Brooks
Ottawa, Canada
RV-6A finishing
(taking longer than Bob Collins)