I recently adjusted the valve clearances on my 4th gen, and I have some observations that might be useful to other folks. First of all: Go ahead and check them instead of blowing it off. It's really not a big deal, especially with the service manual. A few of mine were out, and the motor runs noticeably better after I adjusted them. All you need besides your normal tools is a good set of feeler gauges. Take an extra fifteen minutes and remove the radiator. It's time to change the coolant anyway, right? With the radiator off, there's tons of room to work on the front cylinders as well as the rear ones. Write all your measurements down carefully. Don't just make a list of numbers; note each measurement, "cyl. #3 left intake," or whatever. It will help if they're laid out on paper the same way they are on the motor, like a map. When I put my camshafts back in after changing some shims, I went to recheck the clearances and realized I'd mixed up intake and exhaust shims for one of the cylinders; it wouldn't have happened if I'd laid out the measurements that way. If you need to pull camshafts to change any shims, don't mix up the screws for the camshaft holders; the ones on the sparkplug side of the shaft are different length from the ones on the other side. Before you reinstall the camshafts, go to an industrial supply place and get some Dow Corning Molykote BR-2 Plus grease. Mix a little bit of it 1:1 with the oil you use in your engine. Smear the mixture on the cam lobes before you put the shafts back in, and your motor will love you for it. If none of your valves is out of spec, you will ride happy knowing that fact. If they need a few shims changed, you will feel the difference in how your engine runs afterward.
Good advice, and a great learning opportunity for anyone that is careful / methodical with their repairs, or doesn't trust a shop. Comment: It is definitely not bad at all to just CHECK your clearances; then at least you will know whether to proceed or not. If you do proceed be warned you may need shims that you don't have handy, and it may take time to have to hunt them down or trade with the dealer (some will trade you for yours to give you the right size). Also, Please follow the torquing/order instructions and when replacing the cam bolts after you have had it off. I am proof that you CAN overtighten the bolts and Break Your Cam In Half. They are brittle! Not fun, and almost two hundred bucks for a new one, IIRC.
