1956 exhaust manifold removable

[Dennis Hagen]

Have some leakage at manifolds and considering tackling removing. Any tips?

[JohnD1956]

Make sure it is an exhaust manifold leak and not the plate under the intake manifold.  The 56 has a port to the exhaust crossover under the intake. Its a thin cover and prone to rust through. I replaced mine with a flat piece of 1/4 in steel plate. There are mechanics stethoscopes or use a length of fuel line to find the leak first. 

[Roadhog1951]

Dennis, I long piece of fuel liner is good to find leaks, just put one end in your ear and move around manifold. I took both manifolds off of my 56, 322 with no problems...... Just the normal "rusty nut" stuff, I had to heat a couple of the header pipe nuts to get them off. The manifold bolts came out nice, I installed new bolts with lock washers and didn't reuse the bolt locks, they are still tight 15 pluss years later,,,

Edited November 13, 2019 by Roadhog1951 (see edit history)

[NC-car-guy]

I would recommend against using bolts with lock washers. This will hold the manifold too tight and as it expands and contracts it may crack I am glad roadhog has managed to get 15 years with no problem. As I recall the torque spec on these is very low which is why you use the French locks.  Also no gasket should go between the manifold and engine block.

[Beemon]

Exhaust manifolds are 10-15 ft lbs. Lock washers should be okay IF you use a washer between the lock washer and the manifold, to allow it to flex without binding from the lock washer. The washer will act the same as if french locks were on there in regards to manifold movement. The only issue is that the spring lock could lose temper over time from heat cycling, especially if they're cheap lock washers.

 

People say you shouldn't use gaskets, but my manifolds were warped and I couldn't afford to have them planed. They have not cracked yet, but I also make sure they are not over torqued. I was told they would crack immediately but they haven't and I daily drove my car for the last 4 years. Not saying they won't, but the french locks weren't on there when I got the engine so who knows how long they've gone improper.

[Roadhog1951]

I don't think I used any flat washers, just bolts out of the bolt bin with lock washers , it was soon after I acquired my Buick, I just had to put dual exhaust and glass packs on it! I found the correct left dual exhaust manifold, NOS for $99.99!!!!!!,,,Come to think of it, this was probably before 1999!!!, its all still intact!

[Roadhog1951]

Dennis, those "French" locks are available now, look on e-bay