Intake manifold (1 Viewer)

[Eli Heimer]

Has anyone else had this problem with there intake manifold cracking on a 78 fj 40? If so what would cause this? I’m pretty new to this stuff

 

[charliemeyer007]

I'd say the heat riser spring/shaft is/was sized/broken in the deflect exhaust to the bottom of the intake all the time instead of until it warms up and deverts the exhaust away,

FJ40, FJ55 and FJ60 Land Cruiser Intake and Exhaust Manifold Gaskets, Heat Riser Gaskets and Hardware - Specter Off-Road - https://www.sor.com/cat/044#tab5 #58

 

[71-CRUISER]

Super common if the preheat flapper gets stuck.

You will have to replace the manifold or have the crack welded, which any welding shop can do once it’s off the truck and cleaned.

Its also safe to delete the flapper completely when you rebuild the manifold set, as long as you don’t live in the arctic.

 

[Eli Heimer]

Super common if the preheat flapper gets stuck.

You will have to replace the manifold or have the crack welded, which any welding shop can do once it’s off the truck and cleaned.

Its also safe to delete the flapper completely when you rebuild the manifold set, as long as you don’t live in the arctic.

Would I weld the holes close where the flapper pivots at after I remove it?

 

[65swb45]

Would I weld the holes close where the flapper pivots at after I remove it?

Exhaust manifolds are made of cast iron. Welding cast iron is problematic. The easy route is just to run a bolt the diameter of the flapper shaft through the manifold.

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