Rear Cabin Heat in 7ECA Citabria

[Cowboys Air Ranch 84ME]

is there a hole in the lower right corner of the firewall for the rear heat valve?

Howdy,

Yes. Looks like about a 2-1/4 inch hole just below the lower engine mount to firewall. Looks like pictures of what I see on the internet. There is a aluminum plate covering it up.

The kicker is that I have the duel exhaust and space is very limited. I was told that they had a 90 degree valve for this installation due to the duel exhaust being so close to the mount. Looking for a pic of that 90 degree installation.

This is NOT a Citabria pic, but a KCAB pic I used for reference (See Pic). The hole is in the same place, but my muffler is really close to the lower mount. I can not get a pic of mine without removing the lower cowling, so this is where I stand for now.

Ken "Cowboy" Winiarski
Cowboys Air Ranch (84ME)

 

[Bartman]

Ken,

On one hand, I'm wondering if they had rear seat heat with the dual exhaust O-235 but, on the other hand, your plane was supposedly built with it so I'm wondering why it would be a problem. I'll shoot a pic of the valve when I'm at the hangar and maybe that'll help you to see if there's room for it.

 

[Bob Turner]

When you weigh, keep your logbook at home. That way if they convert your airplane to single place you can go back and compute.

 

[Cowboys Air Ranch 84ME]

Ken,

On one hand, I'm wondering if they had rear seat heat with the dual exhaust O-235 but, on the other hand, your plane was supposedly built with it so I'm wondering why it would be a problem. I'll shoot a pic of the valve when I'm at the hangar and maybe that'll help you to see if there's room for it.

Howdy,

ACA basiclly told me that the rear heat was installed on a single exhaust aircraft, and they do not support the modification, but I do not know if the plane originally had a duel exhaust or single exhaust that was changed over the years sometime.

One thing in the old days was to make the engine breath better (Make more HP) with a duel exhaust and ditch the single exhaust.I am going thru the engine logs and see if there was a exhaust change made somewhere in the past?

Story of my life, like opening a can of worms!

Ken "Cowboy" Winiarski
Cowboys Air Ranch (84ME)

 

[Cowboys Air Ranch 84ME]

When you weigh, keep your logbook at home. That way if they convert your airplane to single place you can go back and compute.

Howdy,

I thought about that, ....... Good Suggestion,........ If it does limit my weight drastically, or maybe not have the paperwork written in the log?

Ken "Cowboy" Winiarski
Cowboys Air Ranch (84ME)

 

[Cowboys Air Ranch 84ME]

Attached is a screenshot of Email from ACA about my Duel Exhaust/Rear heat installation.

Ken "Cowboy" Winiarski
Cowboys Air Ranch (84ME)

 

[Bartman]

the longer side is actually on the engine side of the firewall

 

[Cowboys Air Ranch 84ME]

the longer side is actually on the engine side of the firewall

View attachment 5005View attachment 5006

Howdy,

My hole in the firewall is about 2-1/4 round hole. Not Square.

See post by Big Ed on 3/31/2022. This Pic is somewhat that I believe size should be, but thinking it would be a 90 degree bend as soon as it comes thru the firewall.

Ken "Cowboy" Winiarski
Cowboys Air Ranch (84ME)

 

[Big Ed]

No bend, just sticks out the other side and the scat tube goes on the end. I'll take some closer pics this weekend when I change my oil.

 

[Cowboys Air Ranch 84ME]

No bend, just sticks out the other side and the scat tube goes on the end. I'll take some closer pics this weekend when I change my oil.

Howdy,

Let me clarify,..... I think that the one I need has a 90 degree bend as soon as it exits the firewall into the engine compartment to miss the exhaust down pipe. I know the backside (Under the floorboards) is a straight shot pipe that the SCAT attaches.

ACA says that they do not make that part anymore, so I am wondering if this was a special made/odd part from Ballanca for the duel exhaust models?

My parts book shows a straight pipe setup, but does not specify aor duel or single exhaust. This is a stumper!!

Ken "Cowboy" Winiarski
Cowboys Air Ranch (84ME)

 

[Big Ed]

Ah ok, got it. Have you checked Texas Air Salvage?

 

[Tangogawd]

My 7eca, and now 7gcbc both have rear seat heat with dual exhaust. The heat is taken from the exhaust that supplies heat to the carb, via the carb box. So when carb heat takes priority over the rear heat. Ill try and remember to take picks later

 

[avpro91]

Thanks. Does the frame that holds the door just bolt to the vertical tube on the forward side?

 

[Bruce]

Not sure this will help the rear seat heat valve is installed lower left in photo if your on I pad you can zoom in on it. I’ll look for any more picks.

 

[Bruce]

That’s all I have hope it helps

 

[Cowboys Air Ranch 84ME]

That’s all I have hope it helps

Howdy,

Those pictures are Great !!! Thanks.

I am now looking for the heat valve for a duel exhaust. What I have been hearing is that they only made a few of my vintage with the duel exhaust and rear heat. The valve was different from the single exhaust. ACA Does not make anymore nor do they any more info.

What I have been told is that the valve made a 90 degree turn as soon as it entered the engine compartment and ran up between the lower engine mount and the cowling. I did verify that there is enough room to fit this without burning anything due to close proximity of the exhaust down pipe and muffler.

Will ask around and look hard at fly-in planes to see if i can find this illusive heat valve.

Thanks again for the pics.

Ken "Cowboy" Winiarski
Cowboys Air Ranch (84ME)

 

[Big Ed]

Man, love that new firewall! If I get the engine done next winter, I'll give some serious thought to replacing the firewall while it is off.

 

[Thedude]

I know this is an old thread but it’s the most recent I could find that has some details and pictures on rear heat.

I have a 7GCBC with the dual exhaust and rear heat that is plumbed from the firewall aft but not attached to a heat source. The firewall valve is positioned low and in the center and not what I’ve found should be the factory location by the lower right engine mount strut. I need to go poke around again tomorrow but I didn’t see a free section of scat tubing or free outlet in either heat shroud or an attachment on the back of the carb heat airbox to run it that way. Anyone familiar with a setup like this that can send ideas my way?

 

[Bartman]

Dual exhaust means it's an older GCBC, I don't know what year they started offering rear seat heat, maybe the same year they did a single outlet exhaust system? That would probably be the most expensive option to make it work but you'd need the exhaust and a lower cowl to do it.

Not sure if there's a dual exhaust option with an extra cabin heat outlet on the shroud. If there is you'd have an option to swap out to a shroud with the extra port. Parts manual might show the options if you have a copy?

Good luck with it

 

[Thedude]

Thanks for the reply. It’s a 1969 airframe. The airframe and engine had a complete rebuild 100 hours ago prior to my ownership. Records show the airbox was replaced at that time. The positioning looks like it would have made sense for a hose to route the hot air for carb heat to this when the carb heat was not on. There is scat tubing from the firewall back to the rear outlet and the actuator works to open the valve. Figured out it wasn’t attached last weekend when it kept feeding colder to the back.