Another manifold question (2/79 FJ40)

[Blue60]

O.K. here I go again...

Pulled the manifold off the engine (didn't separate), measured flat along the cylinder head and the lines depicted in the FSM for the manifold face. Reinstalled, torqued in proper sequence, and and lo and behold I have enough space between one of the exhaust chambers big enough to slip a .5mm feeler gauge thru. Thought I had a fale torque so I loosened everything, "jiggered" the manifolds around a bit, and retorqued toward the high end...not much better. Did the same thing twice and went to almost 60 Ft-lb of torque. Closed it up quite a bit, but I can still get a thin feeler gauge thru the gasket and the manifold face on one of the exhaust chambers. What's going on? This is a Toyota OEM gasket, and I'm not so sure I should have to put two of them on. Is it within the realm of possibility that after heating up and expanding it will "close the gap", and after a retorque I'll be O.K.? Or does this sound more like wishful thinking? There were no leaks previously, and I'm somewhat baffled by it all. Any input suggested. I guess the next step would be to have the manfold face checked and "trued" by a machine shop?

Thanks and Keep on Cruising

Dave

 

[JasonH]

Try loosening the bolts that hold the intake and exhaust manifolds together, then torque the manifolds to the head, then re-tighten the manifolds together.

 

[Blue60]

It's worth a shot...I was hoping not to split the manifolds, but I just did it on an 83 FJ60 and lucked out with no broken bolts or cracked manifolds. Might as well put in the heat riser valve while I got them apart...

 

[IDave]

I think that's a good suggestion, too. I've had that work for me in the past. Could definitely be at the root of your problem.

 

[Otis]

Another thing that you might want to check is the surface that the bolt is being tightened up against. After having my manifold planed the thickness of the intake and exhaust manifold flange was slightly off in at least one area. When I tightened the bolt it would really only tighten down on one side. I ended up cutting a washer in half and using it to shim the face so that the bolt would have an even surface to tighten up against. This may not be the same as in your case because you have not had it planed but something to consider...Good luck!

 

[Blue60]

Manifold update

Thanks for all the replies... Had the manifolds faced by a machine shop, they were out of flatness by about 0.76mm (FSM tolerance is 0.5mm). Hung 'em on this afternoon, and they fit puhhrrfect! I couldn't get myself to split the manifolds, and risk cracking, or snapping bolts and having to drill/tap. Anyway, for $40 the ressurection continues...

Cheers, and keep on Cruising!

Dave