Exhaust manifold removal

[kevjimbryant]

I need to replace a cracked exhaust manifold. Can I remove it with the engine in situ and without removing the cylinder head?

[tim wood]

Is this a car with twin strombergs and the crossover pipe from inlet manifold?

Is it the front manifold that’s defective or the rear?

[flatfloor 3.8]

Yes.

[tim wood]

Assume then it’s the rear manifold?

No need to remove the cylinder head.
The bolts that attach the downpipe can be accessed from below using an assortment of extension bars. Or from above with a selection of ring spanners. The crossover pipe will need to be removed and the manifold to head nuts undone.

Be careful of seized studs and threads.
In essence its simple spanner work. I’ve done it with the same set up as you have without removing the head.

[kevjimbryant]

Is this a car with twin strombergs and the crossover pipe from inlet manifold?

Is it the front manifold that’s defective or the rear?

Mine is a 1970 reimported from across the pond and converted to triple SUs. The crack is on the front manifold. I see no cross over pipe, just 4 inaccessible / awkward brass nuts (and potentially a number od studs waiting to break if I do something silly)

[tim wood]

In which case it is as you say just a simple matter of undoing the nuts

[kevjimbryant]

In which case it is as you say just a simple matter of undoing the nuts

Five nuts / studs undone. One stud broken off. Two nuts/ studs being very reluctant to move. A simple matter proving to be very difficult.

[mgcjag]

It's called working on old cars....and most newer cars.....if it was easy everyone would do it.....removeing the exhaust manifolds is one of the easier jobs...you just need to get the nuts off...heat works on most....if the studs shear you can still remove the manifolds then just sort the sheared studs....weld a nut onto the sheared stud works.....Steve

[Gfhug]

My old car challenge is getting the down pipes loose from the manifolds. Nuts were relatively easy to remove and the flanges dropped away but the seal ring is tight and the downpipe won’t drop away

Geoff

[flatfloor 3.8]

Use a bigger hammer.

[Gfhug]

Use a bigger hammer.

I thought I had used a big enough hammer
Maybe, you need to show just where to hit and with how heavy a Birmingham screwdriver! Help, assistance always appreciated

Geoff