Mondeo 02 1.8 zetec - funny noise coming from the engine

[francham]

hope someone can help as I have flummoxed a few friends who are mechanics, got a zetec 1.8 with a duratek engine, done around 56k miles. have had a ticking noise coming from the engine now for a month or 2. a suggestion has been the timing chain. thing is though, no loss in power, no problems starting up and the noise stopped when a friend disconnected the ht lead from spark plug number 1. noise was barely audible up until the oil was changed a couple of months ago, prior to that had some oil burning in the exhaust (lots of smoke from the exhaust) which seems to have stopped now. only way to get it checked out is to have the engine out and taken apart, will cost a fortune. any thoughts would be kindly received.........

[Hometune]

What grade of engine oil was used at the oil change? 5/30, 10/40, 5/40 or 20/50?
When the HT lead was removed this took the load off the components on that cylinder. So I don't think it is the chain either.
Burning oil is caused by one of the following: piston ring to bore wear, valve stem oil seals or over pressurisation of the sump due to breather blockage.
The fact the burning oil has gone would suggest the breather problem as the others are not self-fixing, the only exception being oil control rings having stuck in the pistons and now freed off.
If the noise is a tappety one then it could well be a lazy hydraulic tappet. If the noise is similar to the above but gets worse when you load the engine, then I'd suspect a small end.
Before you start stripping the engine, do a compression test. Any loss here will show which cylinder is faulty and if one is down could point to a valve problem/hydraulic tappet.