I have one more question it just makes sense to ask. Do you want to set the preload on all eight rockers in line at once or do you want to do the preload on each cylinder with the one cylinder time or one valve at a time .
Meaning if I get the zero lash on the last cylinder exhaust side do I find the zero lash on the intake side of that cylinder( then shut the truck off) and run the pre load 1/2 turn on that cylinder only !
Then repeat on next cylinder ?
I just wanted to make sure setting preload on a cylinder and then running the vehicle to check the lash on the remaining cylinders doesn’t throw everything off having preload on some and not on others while the engines running
If I understand your question correctly, things don't move around/interact with
each other all that quickly.
For best results I find that this is the process I usually follow:
1) Get the preload set during initial (cold) assembly reasonably close to right.
2) Get the engine up to normal operating temperature. (Looking for a steady hot, slow idle.)
3) Remove the valve cover and install the modified temporary cover that gives
me access to the rocker arm adjusting nuts.
4) Start the engine, and go through all 8 rocker arm assemblies just like the
48 second video. Again, my only optimization is to set everything 'just quiet'
while the engine is running -- not only does this lessen the 'engine running'
time, but as mentioned earlier this also avoids the rough-running/goosing the
throttle/hot oil slinging thing that we all want to avoid.
NOTE: If I spend ~1 minute per rocker arm, then the engine is running for
~8 minutes. (I don't think it takes me that long to do 1 bank...and I don't
hurry. Methodically, listening carefully as I go.)
5) Shut the engine off. Now I add the desired preload, sequentially through
all 8 rocker arm assemblies. Takes maybe 2-3 minutes total, tops? Not
enough time for any appreciable cooling off to occur.
6) Start the engine back up and make sure that the engine is still running
smooth & quiet. (30 seconds)
7) Shut off engine, remove your temporary home-brew splash guard &
reinstall permanent valve cover.
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It doesn't take that long. And definitely don't stress/hurry through this
running lash procedure. And if you are doing this for the first time it is far
better at 9:00 am Saturday morning after a good night of sleep & a
leisurely breakfast than at the end of a mad thrash/all-nighter. :0)
For a shade tree mechanic / DIYer, being able to get a good valve
adjustment into a pushrod V8 is a rite of passage. It's nothing to be
fearful of, and you don't have to take your SBC to the neighborhood
guru in order to get this really right. And frankly I don't blame you for
having a lot of questions going into this, for there is a ton of well-meaning
misinformation on the interwebs about this procedure.
Done right, doing this adjustment is like going to your favorite library for
a contemplative visit vs jumping into a concert mosh pit.
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PS - I'm quite comfortable with setting valve lash cold per the FSM. And once
I can finally/reliably get to the point where all 16 assemblies are set identically
to each other, then I'll stop performing the 'running preload' cross-check. You
know, I'll manage to get 14 or 15 rocker arms correct, but there always seems to
be that one outlier that is inexplicably off a bit one way or the other? WTF?
(Why The Face? :0)
To summarize, a careful cold preload adjustment IAW the FSM is no doubt plenty
good enough for a solid daily driver. I simply prefer the extra accuracy/info that
a running lash adjustment gives me. And it can be an invaluable troubleshooting
technique when you are faced with an engine that's just been rebuilt by some
unknown entity, and it simply doesn't want to idle as smoothly as the cam specs
would lead you to believe.
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Good on you for asking your questions prior to trying to adjust your valvetrain.
I had just as many questions before I did this the first time. It's OK to be cautious. :0)
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