Manifold heater flap (1 Viewer)

[DenverCruiser]

So I got to it this weekend and am figuring it might be the whole link to my summer vapor lock problem. The question is: should I be able to move it/turn it with my hand-because I sure cant-it wont budge. It is completely rusted up. Also how do I know if it is stuck open or closed? Should I just take the whole thing out if I can? What should I do?

 

[swank60]

I'm not certain on your truck, but on the 60, if that's screwed up, you're supposed to replace the manifold - it's a machined together part.

On your vapor lock thing, does your truck have the carb fan? I think it should, but I'm not positive. Anyway, if that's not blowing to cool off your carb when you shut it off, it'll boil the contents right out of it - causes other problems too. It makes a big, big difference, and is really a common problem on any cruiser.

 

[DenverCruiser]

No fan, actually not even close. They didnt get them untill the mid 70's.

 

[IDave]

Take it out or work it out. If the flat part of the half moon of the counterweight (rear) is pointing up, you are stuck closed. THAT is your problem. If you can get it stuck in the open position (brute force), you'll be OK. You will do damage if you drive it long in the closed position. Try spraying it with PB blaster where the support rod goes through the manifold, then try turning it (flat portion facing out to driver's side). It is limited to a quarter turn. If your spring (front side) is rusted or broken, it can be replaced.

 

[Bob D]

Could you clarify the position for me? My 77 FJ40 has the spring and counterweight on the right side of the manifold. When the manifold is cool the flat side of the half moon is vertical. When hot it rotates to horizontal. Is this the way it should be? I assumed it was but maybe that's my problem with my vapor lock issue too! Could the flap or spring have been reassembled backwards somehow in a early repair?

 

[DenverCruiser]

"You will do damage if you drive it long in the closed position"
That is scary because It has probably been driven like this for many years.

 

[IDave]

The heatrisers for the F engine and the 2F engines are different. I can't vouch for what the 2F does. Definitely the flap is open on the F engine when the flat part of the half moon is vertical. HOWEVER, there must be exhaust blowing to open it fully.

 

[DenverCruiser]

"Definitely the flap is open on the F engine when the flat part of the half moon is vertical"
"If the flat part of the half moon of the counterweight (rear) is pointing up, you are stuck closed"

Alright now I am getting confused again- seems there is some contradiction here somewhere?

So how does this flap work? When verticle it lets hot air shoot up to the base of the intake manifold and heat it up right? Wouldnt this flap then restrict the air from exiting the exhaust?

My "Half Moon" is verticle and stuck. I still dont understand why Toyota had to put this worthless device here.

 

[IDave]

You are right, you caught me contradicting myself. You can tell from the illustration that the flat surface of the counterweight parallels the flap. Flap directs exhaust to underside of carb when vertical.

This mechanism works VERY well to preheat the carb during warmup. Yes, if not maintained, it can cause plenty problems. Just because it was not maintained and is broken, does not make it worthless. That can be said of any mechanical part.

 

[DenverCruiser]

Well I guess I will just soak it on both sides with WD40 and just wrench the hell on it and see what happends.