Originally Posted by dglenn1
Just spent several hours cruising this site and the old site's forums for info on valve checking and adjusting. Still have a couple of questions. (How many times does David have to explain the importance of proper valve clearance before people get it? - Sheesh.)
1) In Paul Sayegh's video
he makes a big point about not reusing the valve buckets once they have been in service. He says they develop a wear pattern and should not be moved around or reused. Most of the advice here including a thread today suggests this is not a concern. Is he just being cautious?
Overly cautious! The cams are ground with a very slight angle which causes the followers to slowly rotate around, and that distrubutes the wear evenly around the surface. If you ever pull one and see any straight line wear, meaning it did not rotate properly, then don't reuse it. If the pattern on the top of the follower is consistent, with no visible circular "ripples" on the surface, re-use it. Also, look at the cam lobes on their tips to be sure there is no undue wear there.
My dealer kept all the take outs, and would swap with users doing all their own work, no charge.
2) When removing the camshafts the advice is to get the #1 piston into mid stroke to get the pistons clear of the valves and unload the valve train as much as possible. The procedure outlined is to get a stick and "feel" the piston position through the spark plug hole. There is also some strong advice not to remove the plugs until the valve train is closed up to reduce contamination.
You should never remove the plugs when you are going to check valve clearance, as any carbon particles that drop down into an open exhaust valve will cause you to get an incorrect measurement when you check that valve. If you are not checking valve clearance, then you can remove the plugs.
What's the best way to position the drivetrain without removing the plugs?
You can never fully unload the camshaft, as there will always be some valves partially open, no matter the crank positon. You can always look at the cam lobes, move the engine until both intake lobes are pointing out toward you at about the same angle from centerline, which will be very near top dead center, then rotate the engine until the cams rotate about 45 degrees, which will put all four pistons about center of travel.
3) Once the chain is securely fastened to the camshaft sprockets and the shafts are removed is there any great concern about the chain slipping off the lower crankshaft sprocket or getting loose enough to skip a tooth? Is it well captured down there? I haven't read where this is a problem but it seems like something to worry about especially if some drivetrain rotation is required prior to reassembly of the camshafts.
The chain is trapped by the housing around the crank sprocket, so will not come off.[/quote]
I'm likely to dive into this tonight so I can run to the dealer tomorrow if I need buckets. These are just fine points, nothing critical as I probably won't need to get into adjustments anyway. Thanks.[/QUOTE]