Been up in Alaska this summer, so I just saw your post. Doing valves yourself is pretty easy. Here's the cheat sheet I use:
ISB VALVE ADJUSTMENT
It's not difficult, especially if you've ever adjusted valves before. I've done mine several times now. I don't bother with the paint mentioned by Chad Sheets. I write down where they are when I first measure them, and where they wind up after adjusting. Checking them again after adjusting is well worth it. After the first couple of adjustments, they haven't changed very much, but it’s still worth it - takes less than an hour. I do them maybe once a year, especially before taking off on a long heavy-towing trip.
TOOLS NEEDED
Big channel lock for unscrewing the round plastic timing cover (manual transmissions)
Small mirror for viewing timing marks more easily
22mm or 7/8 socket, w long-handled ratchet, for turning engine via alternator
15mm ratchet wrench or socket, for removing valve cover
9/16 wrench (a longish box-end works well), for adjuster nuts
5 mm hex key, for adjusters
Feeler gauges
from Steve St. Laurent:
I finally was able to get around to adjusting my valves since I have 100,000 miles on the truck. Here's what I found - intake valves were from . 012-. 015 (optimum is . 010 (. 254mm) - spec is from . 006-. 015) and exhaust valves were . 021-. 024 (optimum is . 020 (. 508mm) - spec is from . 015-. 030). I was blown away that they were still within spec after 100,000 miles - and I haven't been exactly easy on the engine. I set mine slightly tight at . 008 (. 20 mm) on the intake and . 018 (. 46mm) on the exhaust. A note to anyone adjusting theirs - there is a lot of play in the Y from the camshaft to the valves on the 24v engine. I adjusted mine and then cranked the engine over and then rechecked them - it took about 6 times of adjusting them before the numbers were consistent on the next rev (I've adjusted TONS of valve trains over the years BTW). I continued to adjust them until I was able to get a consistent reading for 2 revolutions after I adjusted them.
from Chad Sheets:
Back all the adjustment nuts off on all rockers, then run them down with your fingers until they touch (you will only be able to run down the rockers with no tension on them... the ones with tension will have to wait their turn on the next round when you rotate the engine 360 degrees. Zero the gauge out and adjust for ever how many mm or whatever measurement you want to use.
1. Put cyl #1 on TDC by using the TDC mark behind the crank case breather on the front of the engine. You will have to remove the breather (if it's an automatic, or the round plastic timing cover if manual)... I believe it unscrews. You will see "TDC" stamped at 12 o'clock inside the case and a mark on the fuel pump timing gear. Put that mark on the 12 o'clock TDC position.
2. Remove the valve cover, and mark the following INTAKE valves with a paint marker, 1,2,4
3. Now mark EXHAUST valves 1,3,5 with the paint marker. You should have 6 rockers marked.
4. Adjust the INTAKE valves somewhere between . 15mm and . 38mm. I shoot for the middle of the road . 25mm.
5. Adjust the EXHAUST valves now between . 38mm and . 76mm. Again I shoot for middle of the road about . 57mm.
6. Give all the rockers a good wiggle before removing the gauge to make sure all the play is out of them.
NOW ROLL THE ENGINE OVER 360 DEGREES (180 degrees on the timing mark) AND ADJUST THE 6 ROCKERS NOT PAINTED.
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