David,
My comments are below.
>(1) "HOT"--How do you do that? I do adjust my valves after the engine
>has been running, but then you must remove the plugs and valve cover.
Always loosen the spark plugs when the engine is cold. Reinstall,
you are correct it is best to remove them duing an valve adjustment
(makes the engine easier to turn over).
Usually, since I adjust my valves every 6,000 miles or so (low
annual mileage), it is a simple procedure to just check the valve
clearance. Make a note of any that are off, and move quickly.
To rotate the engine, I leave the car in 4th gear, handbrake off.
A simple "push" with my leg will move the car back and forth
so I can adjust the valve's.
I've mentioned leaving a big sheet of paper on the windshield
with 1 through 8 written on it. Simple matter of putting an
"X" through the number once adjusted.
Also remembering the "9 - fully compressed valve = valve to adjust".
No need to do 1 through 8 in order, as it is quicker to adjust them
out of order.
>(2) The .017" clearance. Back some time, maybe 20 years ago, I was
>using .019", and cold. Don't remember where I got that number, but the
>engine was "rattley". Didn't worry about that too much, because an "old
>wives (or mechanics) tale said, "better a little bit too loose, than too
>tight". I then began using the .017, with the above procedure which
>eliminated the clatter.
For AutoX, I used to play "tricks" with the valve timing. Loose
clearances produced more noise, but seemed to improve the lower
end torque. ;-)
>(3) But, with the engine cooling during my process of adjustment, maybe
>they were ending up *too* tight. Don't know--Do you know which way
>valve clearances go between "hot" and "cold"? In a very complex thermal
>expansion situation, the expansion of the push rod, by itself, would
>seem to go in the direction of increasing valve clearance (but I haven't
>thought that out very carefully).
There is a COLD ENGINE spec of 0.021". I find that is OK when
initially setting up a rebuilt engine, but it is by far best to
adjust everything to be at 0.017" HOT.
>(4) How many miles between valve adjustments? I I do it everytime I
>retorque the head bolts. I just checked my records and discovered that
>the last time I did it was October 1994, some 19,000 mi. ago! Can't
>remember going that long before. As mileage increases, which way to
>valve clearances tend to go, tighter or looser?
Typically tighter. With my 6,000 mile "give it a quick check" what I
am really looking for is if any valves are "sinking" into the cylinder
head. With the OEM Bronze valve seats, you'll get plety of warning
of any possible head damage.
I change oil & filter every 3,000 miles... so every other time,
it is worth while to do a quick inspection of the valves and
carbs. Once everything is set up correctly the first time, most
of the time I am not even changing any valve clearances, but
just confirming they are correct.
>Any facts or thoughts on these matters would be greatly appreciated, as
>you might perceive from the foregoing, I've been a little perplexed
>about this subject.
Cheers,
Tom Walter
Austin, TX.
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