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Firewall Forward - The Master Plan

Rob Erdos

Rob Erdos

Well Known Member
I bought a partially-completed RV-6 project last year. I don't want to admit how many hours I have spent staring at it and reviewing the plans. Getting into a project in the middle is quite intimidating for a newbie. It's essentally a completed airframe, awaiting engine and systems.

I bought an engine (Mattituck TMXIO-320) and the appropriate Firewall Forward kit from Vans. A sensible plan for attacking the firewall would seem as follows:

Before hanging the engine...
*** battery box
*** cabin heat valve
*** oil sensor line along firewall
*** doublers (fuel line, starter solenoid)
*** brake reservoir

After the engine is in place...
*** gascolator (fuel injected engine, but mandatory in Canada)
*** sensor manifold
*** starter solenoid
*** battery master relay
*** oil breather line
*** electrical/sensor pass-through
*** throttle and mixture controls
*** battery cable
*** cabin heat control
*** fuel line

Does that make sense? Are there any other items that MUST/SHOULD be installed on the firewall before I hang the engine? Opinions most appreciated.

Rob
 
FWF planning

Yes and NO, Anything installed with nutplates needs to go on before the engine. It's really hard to install nutplates after the engine is hung because there isn't much room between the back of the engine and the FW. For example, if you are using an external regulator, it needs to be changed at some time in the future and screws into nutplates makes that easy. Another example would be whatever method you are using to pass the throttle cable etc through the FW needs to be installed first. I would preinstall as much stuff as you can.

I found that after I hung the engine on the engine mount for the first time, it has been removed from the FW at least 4 times. Just remove the 6 nuts holding the engine mount to the FW and remove the entire engine and mount assembly. This only takes minutes and makes it easy to find the placement of things as you go.

I just finished my FWF installation and I think the engine might be in place for the final time. Have fun, I found this part of the project to be very satisfying.
 
As much as you can

Hi Rob, welcome to the wonderful world of "I should have done that first!" I am working on the FWF on my very slow build -6A. I have the electrical wired with the obvious exception of the alternator and starter cables. I have all the penetrations drilled with cable feed-throughs. I have the gascolator mounted as well as the oil and fuel pressure sensors. The cabin heat valve is in place and all mag wiring. One other thing to be sure of is to put the elbow on the engine for the oil pressure gauge (with the restrictor). You'll find lots of posts here about doing that because you won't get it in once the engine is hung. If you look at some of the builders web sites you can find a lot of good pictures of where stuff goes. Are you putting in the firewall mounted battery instead of the cabin mounted? Most builders do and I decided to go that way as well. Good luck and happy building.
Paul
 
Doesn't seem obvious but ...

everything that was said seems logical, put as much on as possible. I've spent the last two weeks doing F/W mounting tasks. Wasn't on my 'list' yet, but then each item seemed to beg for installation in preparation for doing a lot of the other wiring, or closing up the forward cabin. For example, once the oil filter F/W recess is riveted, the easy access to the inside to bolt, rivet or wire is greatly impeded. (Unless you have a building buddy on the inside).

Visualize the process of adding something AFTER the engine is hanging in front of the F/W and you can imagine the complexity.

Try www.mykitlog.com and do a search for RV-6/6A and you'll find some company. Or even the -7 or -9 pages. They're all about the same in concept.
 
Rob, This might help, and it is cheap........

Call Van's and order RV7 drawings 19, op26, op27, op28, and 0p29.
 
Why stop there ...

gasman said:
Rob, This might help, and it is cheap........

Call Van's and order RV7 drawings 19, op26, op27, op28, and 0p29.
Click to expand...

get a whole new 'refresh' of the drawings (plans). Well worth the $, and contains some of the updates (for example RV-7/7A) FWF plan instead of the original RV-6/6A layout.
 
As much as you can...

Hi Rob,
I'm in Gatineau (CYND). You can come and see my RV-7a. It might be a lot easier for you to look at the real thing and we can chat around what to do before hanging the engine.... Email me if you want .([email protected])

Michel
 
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