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So this would involve lifting the cam covers and measuring the lash with a feeler gauge under the heal of each cam lobe. This will require turning the engine over by hand. The valves that are out of spec' are noted. The cams are then unbolted, lifted and/or removed, larger or smaller shims are installed under the bucket tappets of the out of spec valves (available from your dealer). The cams are then reinstalled paying particular attention that the cam timing has not inadvertently been affected.
The valve lash is then checked again and if correct, the cam covers are replaced.
Yep, but Ford does not intend for them to be a 'normal' maintenance item. All Ford mechs I ever talked to acted like I was crazy for even mentioning it. No shims carried in house at dealerships here. Whatever you do, do NOT accidentally turn motor while a shim out, will butcher parts lickety split. These motors will not get noisy like the old solid lifters from the '60s. The clearance generally CLOSES UP instead of loosening since the valve seat/valve interface will wear faster than the other parts, allowing valve to sink deeper into head and tightening up the distance. Make sure if those cam caps come off they go back EXACTLY where they came from as the parts are not interchangeable. They are letter marked to aid that location.
Look around on the web, there may be a tool to hold down tappet while cam moved to different position and shim removed while tappet all the way down. All the hot rod bikes do that to avoid yanking cams. Gotta be careful not to bend valve though since will be held open while at different spot than normal running engine. Careful thinking will stop that.
Whatever you do, do not go anywhere around the minimum clearance, or below 5 or 6. Thinking stock clearance was .006"-.013", but it's been awhile. When you get close like that, the cam bearing clearances will cover up possible negation of valve clearance by the clearance moving around because springs push cams around in their holes. Holes could be bigger than clearance meaning one could be reading a clearance when there is none while motor actually running. You can sometimes get say .005" on a valve, roll it around to check again and find 3 or 7 in same location even though you swear you're in same spot. From cam moving around. It centers up on the oil wedge while running so somewhat unclear just what true running clearance is. Far better to stay in the middle of the range. That's why Ford made the clearance so big, also because they tighten up as mentioned. The tappets really run quite quiet even then.
I believe there is some sort of Ford tool that bolts to pairs of cam caps to allow holding down the tappet while cam moved away. Then shim can be popped out without removing cams. Used on later Focus models. Similar to how the motorcycles do it.
One or 2 may tap a bit when cold, but it goes away when hot unless something is wrong. I adjusted my tappets after a valvejob. The intakes were pretty much OK but the exhausts got cut quite a bit. I did not change shims, instead custom cut the valvestem tips to get clearance.
Just because someone else tells you he has never had trouble before does not mean you won't. A steady loud clicking could be something as simple and deady as a valvelock pulling through retainer to destroy motor. Rare, but it does happen. I have seen that many times on older big V-8 run with no maintenance but it should be much harder on 4 valve motor since no spring pressure to speak of.
This should sum up exactly how the Zetec valve, tappets, and noise associate:
It is necessary for a clearance to exist between the tip of each valve stem and the valve operating mechanism, to allow for the expansion of the various components as the engine reaches normal operating temperature.
On most older engine designs, this meant that the valve clearances (also known as tappet clearances) had to be checked and adjusted regularly. If the learances were allowed to be too slack, the engine would be very noisy, its power output would suffer, and its fuel consumption would increase. If the clearances were allowed to be too tight, the engines power output would be reduced, and the valves and their seats could be severely damaged.
The Zetec engine employs hydraulic tappets which use the lubricating systems oil pressure to automatically take up the clearance between each camshaft lobe and its respective valve stem. Therefore, there is no need for regular checking and adjustment of the valve clearances, but it is essential that only good-quality oil of the recommended viscosity and specification is used in the engine, and that this oil is always changed at the recommended intervals. If this advice is not followed, the oilways and tappets may become clogged with particles of dirt, or deposits of burnt (inferior) engine oil, so that the system cannot work properly; ultimately, one or more of the tappets may fail, and expensive repairs may be required.
On starting the engine from cold, there will be a slight delay while full oil pressure builds up in all parts of the engine, especially in the tappets; the valve components, therefore, may well rattle for about 10 seconds or so, and then quieten. This is a normal state of affairs, and is nothing to worry about, provided that all tappets quieten quickly and stay quiet.
After the vehicle has been standing for several days, the valve components may rattle for longer than usual, as nearly all the oil will have drained away from the engines top-end components and bearing surfaces. While this is only to be expected, care must be taken not to damage the engine under these circumstances - avoid high speed running until all the tappets are refilled with oil and operating normally. With the vehicle stationary, hold the engine at no more than a fast idle speed (maximum 2000 to 2500 rpm) for 10 to 15 seconds, or until the noise ceases. Do not run the engine at more than 3000 rpm until the tappets are fully recharged with oil and the noise has ceased.
If the valve components are thought to be noisy, or if a light rattle persists from the top end after the engine has warmed up to normal operating temperature, take the vehicle to a Ford dealer for expert advice. Depending on the mileage covered and the usage to which each vehicle has been put, some vehicles may be noisier than others; only a good mechanic experienced in these engines can tell if the noise level is typical for the vehicles mileage, or if a genuine fault exists. If any tappets operation is faulty, it must be renewed.