This article is for the 2.0 DOHC I4 Zetec engine in the Ford ZX2, and probably works on other cars with the Zetec as well. To check the valve clearance when installing a new high performance cam:

1. Remove the original camshafts and tappets.
2. Measure the shim thickness on each tappet shim disc (98-99 models) or solid tappet (00-03 models) and record the info, then organize the shims or tappets in a group from thinnest to thickest order. The solid tappets have a metric dimension stamped on the inside of the bottom of the tappet - hopefully the numbers are still readable, that will make the job easier.
3. Insert the lash caps and the thinnest tappet with thinnest shims on the two #1 cylinder intake side valves only. Lube the tappet top and cam with oil, and drop the new intake cam in it's perches with #1 cyl lobes facing the firewall (#1 TDC).
4. Hold the cam down with your hand and slip a feeler gauge between the tappet and cam - if you feel you're lifting or rotating the cam from it's perch then the feeler gauge is incorrect for the given clearance. you should feel only a slight drag on the feeler gauge as it slides in/out from between the tappet and cam.
5. If the clearance is good (intake - .008"-.010", exhaust - .012"-.014") then the tappet you just checked is now correct, and can be placed in a numbered egg carton with it's respective shim.
6. If the clearance is too large, repeat the process again using a tappet shim you have that is the next thickness up. repeat until you find the right match, and place the tappet and shim in the egg carton.
7. If clearance is too tight, then figure out what the net reduction in clearance needs to be for that tappet shim and write down/order the shim or tappet with the correct thickness. Same goes for if the step above doesn't make the largest clearances go away.
8. Do the same with #1 exhaust cam and tappets, except the exhaust cam needs to point toward the radiator at a 90 degree angle (also #1 TDC). Repeat the rest of #2.
9. Remove the cam and tappets for cyl #1 and put tappets with the correctly found shims in the egg carton, then repeat the operation #2 and #3 for cyls 2, 3, and 4.
10. Once you have all your info, it's time to see which shims you can re-use and which you need to order. typically, 4-6 new shims/tappets are needed out of the 16 you have presently.

Both the shim type tappets and the solid tappets are interchangeable between early style (98-99) and late style (00-03) zetec motors. For performance sake the solid tappets are preferred due to their lower valvetrain weight and slightly larger tappet surface, but the shim types work fine in most cases as well, plus the shim type tappets have a larger adjustment range (1.5mm adjustment span) versus the solid tappets (0.6mm adjustment span).

Also see

• Ford Escort & ZX2 section for the entire index of all Ford Escort and ZX2 related articles.