Exhaust Manifold Assembly

[tartan18]

I'm a newbie wrencher and I need some advice about how to re-assemble my cylinder head. It was leaking coolant and oil so I pulled it off and discovered 8 holes in the intake and exhaust manifolds that needed to be helicoiled. It is a 1800 head on a standard 1975 engine block. I got the intake side put back together but for some reason the exhaust side doesn't want to slide down on the newly installed studs. The manifold seems to be too tight and won't fit the studs. Any hints of how I can proceed? Should I try to install the studs through the manifold ?

[pastaroni34]

You're going about it the correct way, studs first, slip on manifold afterwards. If the threads were drilled and helicoiled, it is possible the studs are not installed square to the head/gasket face.

Does the manifold gasket fit OK?

Which manifold do you have? Some aftermarket ones use relatively thin flanges that warp and it might not slip on so easily. Some are also cut to give the manifold relief from expansion and can be difficult depending on how the manifold stress relieves itself from many heat cycles.

[tartan18]

Hi Jason, Yes the gasket fits fine and I used the ARP studs that I bought from you. I am thinking that the machine shop drilled the new holes a bit off center. The gasket fits fine after I "drag" it down the new studs. This is on a stock 1800 manifold.

Should I take this back to the machine shop?

[pastaroni34]

It pains me to say it but if the holes are drilled off center I don't think you have much in the way of options for fixing them.

The gasket should slip on easily without binding. Once it is on, do the exhaust port holes line up with the gasket holes correctly?

Does the manifold go on at all? Or does it go partly on and then get stuck/bind?

I have used the ARP studs on many engines but I have not tried every manifold out there. It could be the studs are a little bit longer and not allowing the manifold to properly seat.

You might have to drill/ream out the manifold holes to get the necessary clearance.

[tartan18]

Thanks Jason ... my cylinder head goes back to the machine shop tomorrow. I am sure that the exhaust stud helicoils were installed slightly off center. Darn.

[tartan18]

Just to close out this thread -- all is well. Using a few well placed whacks with a small hammer I was able to get both the intake and exhaust manifolds seated. Thanks everyone for your ideas. Once again Fiat Slider Forum rocks.

[pastaroni34]

Great! Glad you followed up with the solution.