I’m wondering how much heat valve stem seals can withstand. I’m asking because a machine shop screwed up my lower intake manifold and also gave me bad advice which resulted in me needing to use JB Weld on a $600 set of heads I had recently purchased. I’ve got the highheat epoxy which is rated for 800 degrees and the area in question is close to the water jacket. Before I take a chance of ruining my engine with a broken piece of JB Weld I want to place my heads in the oven at 550 degrees for a few hours and see how the epoxy holds up. I cleaned the area with denatured alcohol and carb cleaner and also filed it down before applying the putty, so I’m keeping my fingers crossed. Just wondering if I need to yank the seals off beforehand or not.
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