Air cleaner intake help

[Jayboundless]

Hello folks,

I’m brand new to FJ40 ownership and need some assistance telling me the air intake system functions on my vehicle. Here are the pertinents: 1976 FJ40 see attached photos. There is a spring loaded butterfly valve midway Between the air intake horn and the air cleaner. It appears that it allowed either exhaust heated air or fresh air from entering th air cleaner assembly. There is no hardware or cable attached to the actuating lever, so it is closed under spring pressure, drawing from the heated air side. That heated air hose is not connected so it is essentially drawing fresh air but my OCD will not allo me to just leave it. I want it to work correctly and draw air from the air horn attached near the grill.

I’ve done a lot of looking online at pictures and diagrams but I do not see this particular set up. For this style of air cleaner I have seen some that have some sort of a vacuum actuated system that would regulate between warm or fresh air. Can someone tell me how this system worked as in my case where it is a manual functioning butterfly valve?

Thanks in advance!

Obligatory vehicle shot!

 

[Eric_FJ40]

Looks like a california spec to me. That valve is controlled by a "thermo wax" if I recall correctly. The arm you point to with the slot will move with a change in temperature and move the flap open or closed. In one position it directs ambient air from the front of the vehicle, in the other position it directs heated air from off the manifold. In the 4th photo, you can clearly see the elbow duct coming off the exhaust manifold. There should be a section of duct that connects this elbow up to the opening on the underside of the air cleaner arm - directly above it.

Looks like a lot of your smog equipment has been removed as well.

Also missing is the air horn that would be on the front of the engine compartment over the left headlight and the duct that connects it to the arm on the air cleaner.

 

[Jayboundless]

Looks like a california spec to me. That valve is controlled by a "thermo wax" if I recall correctly. The arm you point to with the slot will move with a change in temperature and move the flap open or closed. In one position it directs ambient air from the front of the vehicle, in the other position it directs heated air from off the manifold. In the 4th photo, you can clearly see the elbow duct coming off the exhaust manifold. There should be a section of duct that connects this elbow up to the opening on the underside of the air cleaner arm - directly above it.

Looks like a lot of your smog equipment has been removed as well.

Also missing is the air horn that would be on the front of the engine compartment over the left headlight and the duct that connects it to the arm on the air cleaner.

Hmm, the only thing I’m finding regarding google searches of “thermos wax” has to do with Diesel engines. Did they also have this system on gas engines? Yes, the smog system has been removed. I assume the previous owner didn’t have the tube hooked up between the exhaust manifold and cleaner because they didn’t believe the buttery valve is functioning correctly? Is there more to this valve on the internal part of the air intake that I am just not able to see? Any others they can weigh in?

 

[Solace in Solitude]

Hot Air Intake Engine Location

 

[Jayboundless]

Alright, so I think I’m beginning to understand how the system works now. It appears that my year of vehicle, it uses a mechanical temperature actuated flapper valve to open (to fresh air). It appears that later/earlier models had flapper valves that were vacuum actuated. Concur?

So my next question is: Before I purchase the missing hose, Can I test its functionality by starting the vehicle (maybe I don’t even need to start motor) and point a hairdryer or paint stripper gun up through that hot air intake and if the butterfly valve opens in reaction to the warm air?

 

[Eric_FJ40]

Alright, so I think I’m beginning to understand how the system works now. It appears that my year of vehicle, it uses a mechanical temperature actuated flapper valve to open (to fresh air). It appears that later/earlier models had flapper valves that were vacuum actuated. Concur?

So my next question is: Before I purchase the missing hose, Can I test its functionality by starting the vehicle (maybe I don’t even need to start motor) and point a hairdryer or paint stripper gun up through that hot air intake and if the butterfly valve opens in reaction to the warm air?

That's the gyst of it. You could probably just check the position of the flap while the vehicle is cold, then go for a short drive to warm things up and check the position then. Come to think of it, I've never really checked mine for function either - and I've got all the CA smog gear intact.

Not sure about the vacuum actuated versions - could have been the later models that had those.

 

[GA Architect]

GATES FLEXIBLE AIR DUCT HOSE 55MMX500MM - 7743-00555

Here is that hose on my rig.

 

[Jayboundless]

That's the gyst of it. You could probably just check the position of the flap while the vehicle is cold, then go for a short drive to warm things up and check the position then. Come to think of it, I've never really checked mine for function either - and I've got all the CA smog gear intact.

Not sure about the vacuum actuated versions - could have been the later models that had those.

So I tried the hair dryer idea this afternoon and nothing happened. The valve didn’t open and I figured it was imop. I live in Nebraska and I haven’t been able to drive it for about 3 weeks due to snow and salt on the roads. But today the roads had dried up enough for a quick spin. When I got back, I took a look, and behold!...the butterfly valve was open, even though the heat riser tube is missing. I guess after awhile just the heat in the engine compartment was enough to trigger the mechanically operated thermostat and it opened. Now I just need to source the HAI tube, and the fresh air intake tube and horn. Thanks for all the help.

 

[Eric_FJ40]

Success!

 

[spotcruiser]

Can I ask where you bought that? It looks perfect, but all I can find are European sources. Thanks.

GATES FLEXIBLE AIR DUCT HOSE 55MMX500MM - 7743-00555

Here is that hose on my rig.
View attachment 1854240

View attachment 1854241

 

[GA Architect]

Can I ask where you bought that? It looks perfect, but all I can find are European sources. Thanks.

And the UK is where it came from. I also purchased a 2nd one, being shipping wasn't too much. I think it took just a few days to get here.