exhaust manifold leak help

[newtoit]

I have a 1964 Lotus S-2 with the intake and exhaust manifold on the same side. Have replaced the gasket but continue to have a slight leak in one small place on the exhaust side. Any ideas on how to repair without a new header? It is original and would like to preserve, if possible.

[scannon]

Check the head and manifold surfaces for flatness. Have them surface ground if not very flat. You probably know this but you torque manifolds from the center out in several steps. Miss-torquing them will cause warping.

 

Excessive heat will warp them. BTDT with turbo manifolds many times.

[newtoit]

thanks! will remove and get that done ASAP!

[TheDingo8MyBaby]

Assuming this is a pre-crossflow since you have a series 2, getting the headers to seal is not an easy task. Keep in mind, it is just as important that the flange thickness of the exhaust manifold and intake manifold match since they are both held by the same fastenener and you want an even an even load across them. I've sometimes added shims to either the exhaust or intake side depending on what was leaking to get it to seal properly.

 

It's also important to retorque regularly with the pre-crossflow.

 

-Geoff

[jlumba81]

If you can find the correct bolt size and thread pitch, stage 8 header bolts would prevent them from loosening.

[scannon]

I have the Stage 8 lock nuts on two of my turbo cars between the exhaust manifold and turbo. I also have inconel studs in the manifold.

 

You need to spend time fitting them so the eccentric is fully against the manifold or other stop otherwise they can loosen a bit until they do hit something solid. This will likely involve grinding a bit off the eccentrics to get a tight fit.

[newtoit]

looks like the flanges are the issue. Exhaust side is narrower. Any recomendations on shim types?