MK1.5 2002 Focus 1.6 Zetec SE - very noisy top end

[Dr Doofenshmirtz]

The engine sounds like there is too much of a gap between the cam and follower. It sounds like metal on metal tapping and is quite loud. Definitely coming from the valve area. Engine is well down on power.

I lifted the rocket cover to see if there was anything obvious - all looks fine.

It was fine the day before, it happened from the off the next morning.

Any ideas as to what it could be?

[finlo]

Have you checked the oil level?

[Dr Doofenshmirtz]

Yes all levels are fine - it didn't run low.
I'm starting to suspect maybe the belt has slipped knocking the timing out - or maybe one of the valves isn't fully retracting creating excessive valve lash which is making the clacking noise.

[JONATHAN_11_80]

Hi,

The ford sigma (zetec se) engine is usually a strong motor if the oil quality and levels are maintained. Failing this and they do tend to suffer. The noise you describe sounds like bottom end noise. If its big end noise you will usually get the knocking on overrun i.e. blip the throttle and noise comes in as the engine slows down. Top end noise is usually a fast tapping noise. These engines do run solid followers and tend to have noisy top ends anyway. But clacking sounds more serious.

[S0 What]

Get the belt cover off and check the adjuster hasn't collapsed or come loose? also have a good look at the crank pully they can seperate and make a god dam awfull noise ? i have seen cam bearings crack as well but not at all a usuall thing to happen, one other issue sometimes taken for engine rattle is the clutch fingers snapping, does it get worse when you put the clutch down ?
Not doubting your ability to tell where a noise comes from but allways assume the ohter guy is an idiot till he proves you wronge

[Dr Doofenshmirtz]

Thanks for the replies, but I was suspecting more and more that the timing belt had slipped...and it had - by about 1 tooth!
No idea how - I can only guess whoever did a belt change last didn't torque up the bolts properly.

The crank bolt and cams aren't keyed on the Zetec. If you loosen the bolts, the pulleys are free to rotate. There is no woodruff key like on most.

To set the timing, you have to remove a blanking bolt in the crankcase just behind the off-side prop shaft...near the intermediate prop bearing, and insert a crank locking pin.
You then slowly rotate the engine (by hand!) till it comes to a stop - it should now be at TDC.
You then whip off the rocker cover and you should be able to insert the cam locking bar... I couldn't.
So with the crank still at TDC, I loosened the cam pulleys and carefully rotated the cams a few degrees until I could slide in the locking bar.

Job done.
The crank locking pin and bar cost about £8 from eBay.

[JONATHAN_11_80]

Good job