The threads in the injection pump are perfect. It’s just the Torx female end.@JHZR2 you can get very close to the original screw here:
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If the threads in the casting are buggered, helicoil will provide plenty of strength. There’s enough meat in the casting to allow for the helicoil.
One other point - this fastener had a large head - this helps spread the clamping force over a large area to prevent distorting the cover.
Whatever you put on there - use a washer of the same size as the head to spread the load.
Fortunately no need to do anything else. Unless I apply anti seize or whatnot.
Interestingly these little screws didn’t come with washers. There isnt a ton of space to add bigger ones than the head, but it’s worth a look since this seems to be a common leak prone spot on these engines.