Bought the above and have done it up(rebuild without removing the engine). Now that it is going again, it has a very clattering, uneven engine rattle at low idle. Above 2000 there is nothing. Timing chain tensioner is on its limit, but there is still tension in the spring. 28000 miles on the clock, and, by the state of the bolt heads, nobody has ever touched it. Any ideas???? Listening with my trusty screwdriver pressed to ear, it seems to be coming from the lower gearbox. Primary chain???