what you mean shallow bolts ? on the water pump ?
mine have actually mushroomed from hitting the chassis on hard corners :O
im waiting on it failing from the stress of it all, not looking forward to engine out to renew it either.
im putting my primera/micra exhaust on tomorrow with a decat pipe + laser sports backbox. i predict it will still be too restrictive tho
couple of other boys are running standard bore with no prob's.
i still need to weld my sills up etc.
how to diagnois water pump failure ? overheating on the dash guage ?
what bore pipe you going for ?
what you idling at with no system on ? just manifold ? Cold + warm ?