Good morning all. Assembling the Cobra Jet for my KR and getting ready to put the exhaust manifolds on. The manifolds have been surfaced and I checked the head surface; it's straight and true. I've had a couple of opinions on gaskets vs no gaskets.
Any opinions? I'm not concerned with being "correct", I just don't want leaks. As you all know it's a bear to remove the manifolds in the car. Some say gaskets, one other said no gaskets, just a thin layer of grease to the manifold surface.
Hmm... what to do. :-\
Thanks, Pete.
Quote from: Peter L. on March 08, 2023, 08:12:49 AM
Good morning all. Assembling the Cobra Jet for my KR and getting ready to put the exhaust manifolds on. The manifolds have been surfaced and I checked the head surface; it's straight and true. I've had a couple of opinions on gaskets vs no gaskets.
Any opinions? I'm not concerned with being "correct", I just don't want leaks. As you all know it's a bear to remove the manifolds in the car. Some say gaskets, one other said no gaskets, just a thin layer of grease to the manifold surface.
Hmm... what to do. :-\
Thanks, Pete.
If the no gasket was good enough for millions of Fords with no significant warranty issue's then it is good enough for me regardless of if factory correct or not. For extra preventive maintenance insurance I typically surface both intake and head when rebuilding a engine or just surface the exhaust manifold if not rebuilding the engine. I add a "thin" layer of high temp silicone to the surface of ether before bolting on the manifolds . If any of the thin layer of high temp silicone squeezes out I use a razor blade or pick to get rid of it. I have high confidence in this procedure as it is typical of what I and numerous other enthusiasts and restoration shops alike do. I have not heard of a issue doing this way.
Great! Thanks for the advice.
Not to say that non-visible silicone is not an option but have found success with graphite applied to the two freshly machined surfaces work out well for me in the past. Just like Ford did and no worry about someone seeing the produce in the end results. Just another option for those restoring or just building some of these fine machines :)
The factory shop manual advises to coat the mating surfaces with lithium grease. It works fine and never leaks.
Just to clarify.
Was taking my information from the engine build (65, 66 and 69 or 70 if I recall correctly) instructions.