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Firewall space/ layout


Well Known Member
I’m about to mount my battery (small one) on the firewall in the prescribed spot for the taildragger per the plans. Before I do that- will I have enough space to also mount the oil cooler, and find somewhere to mount the inverted oil system (Christian) with the relays and pass-throughs?
Seems to me that it might be a good idea to raise the battery box up so I have room under it for the inverted oil separator. Which side is the firewall mounted oil cooler usually mounted? Anyone have all this stuffed into a 7?
Stock...and not stock...

For the PC-680, I used the location as depicted in DWG 31A without modification.

I mounted a SW 10599R, with room to go all the way up to a SW 10613R, on the left firewall, just below the mixture, propeller cable penetration points. The mount is formed by a couple of AA6 3/4x3/4x.063" angles running from the recess down toward the left bottom corner of the engine mount, this causes the oil cooler to sit at a bit of an angle from the horizontal.

I can easily route a 3" - 3.5" SCEET duct here, although I did have to fabricate a custom diffuser to adapt the round duct to the rectangular face of the oil cooler.

Some pictures attached of an installation in another RV-7 as well as the diffuser.


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I have a very non standard firewall setup, but I have fit all this stuff on there. I tried to use the RV10 oil cooler mount and couldn't make it fit, but have seen others that have made it work. My new oil lines should be here tomorrow for the inverted oil system, so I'll try to grab a bunch of pics. I also had to do a custom nozzle and diffuser for the oil cooler ducting.
Might be a good idea to gather all your goodies (or mockups of them) and trial fit everything before hard mounting firewall items

Basically the stock battery is positioned to facilitate easy battery removal clearing the engine mount and upper firewall forward tilt Most 6/7 firewall installations I've delt with had the oil cooler on the left (drivers) side.
Thank you all! I especially appreciate the pictures. Keep ‘em comming. Seems like the inverted oil tank needs to be higher up so the battery may be low on the right as depicted in the plans. Oil cooler mounted on left side of the firewall.

I don’t have my engine mount yet so I’m not sure about interference there but thi s has helped.
Here's where I'm currently at with my firewall. On the pilot side the battery is mounted as high as possible in order to best fit the Vertical Power PPS box on the lower portion. The air/oil separator gets mounted to the engine mount. The inverted oil valve got mounted on the copilot side at the correct height, next to the smoke oil passthrough. I've seen the 13 row cooler in a similar spot using the RV10 angled mount, but I couldn't get it to fit. So i mounted mine flat and made some ducting to work with the show planes oil cooler door with electronic actuator.


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Great pics! Thank you. Man, that is tight! Is the inverted ball valve supposed to be down that low? I think I remember 1 part of the system has to be at a precise height, but I’ve seen pics very different in design.

Great pics! Thank you. Man, that is tight! Is the inverted ball valve supposed to be down that low? I think I remember 1 part of the system has to be at a precise height, but I’ve seen pics very different in design.

So I stole this concept from another builder blog but basically don’t mount anything on the fw until you have your engine mounted on your engine mount , leave the mount on the engine with engine hoist , this allows you to move engine in and out , you can temp mount everything and move engine and mount into position see how things will line up . Worked great for me .
Oil cooler

I have the RV10 oil cooler on the RV10 mount. Butterfly valve is in the flange mounted to the #4 baffle.
Standard battery mount and location for a 7A. I wouldn't want to wedge a smoke system but it's probably doable. Lower Starboard side.

Great pics. That is very tight. Questions
Is that rv10 oil cooler baffle stock size? It really looks large in there?
Also, is that an aftermarket exhaust? Look different than mine. Looking good!
Just happened to see this thread. I just finished up most of my FWF stuff and I have everything you mentioned stuffed under the hood with the exception of an oil separator. Mines a 390 so the prop governor is on the front, which certainly helped. free up some space on the aft side.

Theres a limit to how high you can move that battery and still get it out of the battery box due to the engine mount tube above it unless you build a battery box that doesn't require pulling the battery up to get it out of the box.

With some careful planning and mockups its doable, but I absolutely wouldn't bolt up anything until the engine mount is on otherwise the potential for interference is quite high.

Theres so much stuff back there that it's kind of hard to capture all the chaos with one photo, but here's a picture of mine. If you want to see anything in particular or need approximate layout measurements shoot me a pm.



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Wherever you put the battery, try to keep from putting anything above it so that the battery can be removed without taking the battery box off the wall. I thought I did this, but later additions of hoses and wire bundle loops foiled my access.

As said before, try cardboard mockups taped to the firewall for equipment.