[KTL]

Good point about the JB weld. That would definitely affect the ability of the cam plate to seal. But remember also that the chain box has some M8 nuts that fasten it to the case, along with a couple of alignment dowel sleeves in the case to reliably locate the chain box repeatably every time. The cam plate has some "float" to it due to the lack of restraint on the OD by the o-ring. Meaning the o-ring allows for some misalignment to ensure the plate is sealing on the cam housing. But if the chain housing is a bit off due to the JB weld interference, that could be the source.