In my other posting I meant to explain a simple method of adjusting the valves--but didn't--guess I got tired and faded away. This method will work for inline 4's or 6's -- or 8's for that matter. In the case of the 4 cylinder -- #1 piston and #4 work in tandem--#2 and #3 work in tandem -- when one piston is on it's compression stroke the mate is on it's exhuast stroke--You want to adjust each of the valves with the cylinder on the compression stroke. In order to keep track start with adjusting #1--then you follow the firing order 1-3-4-2. Take the plugs out so you can crank the motor by hand with the fan belt or with a wrench on the bottom pulley. To adjust #1--crank the motor slowly until you see the #4 exhaust valve has past fully open--continue cranking until the exhaust valve is nearly closed--at that point the intake of #4 will start to open--stop there at that point of the exhaust and intake "rocking" opposite each other. Now adjust the intake and exhaust of #1. The next up to adjust is cylinder #3 (firing order) so you will watch #2 cylinder exhaust valve going through its sequence--as before when #2 exhaust valve and #2 intake are "rocking" you can adjust intake and exhaust of #3 cylinder. Next up is #4--watch #1 valves for "rocking" -- and finally adjust #2 valves when #3 are "rocking". You will have turned the motor through 2 revolutions at that point. While there may be cam flex as another poster mentioned--it is not something you need worry about--you would need a dial indicator to measure the difference. Adjust each valve so they feel the same--there should be a light drag on the feeler gage--if you have to force it into the gap your too tight--if it passes through with no resistance you're too loose. Use a short (6 inch) wrench for the lock nuts so as to not overtighten them (B18/20 adjusters are soft). When your done with the valve adjustment take a compression test so you know where you stand on that basic indication of motor condition.