Rocker arms loosening 93 5.7 tbi

[Road Trip]

I keep reading topics about rocker arm preload being to tight and valves open could cause no compression meaning Zero .. which is a weird result imho .. but low compression is pure mechanical failure. So might I be dealing with a bad adjustment on # 8 cyl it never had this stumble when I bought the truck even though I had weird lifter issues going on .
This is depressing as hell .. I wanna try to adjust the # 8 and see if that is why .

You should recheck the preload adjustment on #8 cylinder.

Understand that if the lash is set too tight that this means that A) you have
physically pushed the pushrod plunger all the way to the bottom of it's travel,
so that you now B) are holding the corresponding valve off of it's seat.

This would explain why there is no compression in a cylinder with the
valve lash set incorrectly like this. Take your time, and let us know how
many 1/4 turns each valve took before the light clatter starts.

Let us know what you find.

 

[A97obs]

So this is the likeliness in one scenario or the best case . If not what else could have happened if we’re keeping failed rings out of the equation.
Just seems zero and the rest are all spot on great readings made no sense . I didnt wanna thing that worst

 

[A97obs]

You should recheck the preload adjustment on #8 cylinder.

Understand that if the lash is set too tight that this means that A) you have
physically pushed the pushrod plunger all the way to the bottom of it's travel,
so that you now B) are holding the corresponding valve off of it's seat.

This would explain why there is no compression in a cylinder with the
valve lash set incorrectly like this. Take your time, and let us know how
many 1/4 turns each valve took before the light clatter starts.

Let us know what you find.

I didn’t even need to use the splash guard at idle nothing spilled over I backed the nuts off until I heard chatter then one at a time in smaller increments than 1/4 turns I clockwise the ratchet until I ever do slightly stopped hearing chatter . Did this on all 8 passenger bank
Then I shut the truck off and ran 1/4 turn 12 noon to 3pm preload on all 8
I did not run 1/2 turn (12-6)
Just a 1/4 turn . It sounded good but had the miss it has had the miss ever since the first random clatter occurred when on my road trip . The truck never missed before that so this miss has been before the adjustment also . The plugs looked horid the cap was crusty so I did all the plug wires cap rotor etc to try and alleviate the miss before I went and did the compression check .

All I know is zero compression is odd it should be low or read something

So that’s what I attest it to the nut adjustment maybe !

 

[Road Trip]

I didn’t even need to use the splash guard at idle nothing spilled over I backed the nuts off until I heard chatter then one at a time in smaller increments than 1/4 turns I clockwise the ratchet until I ever do slightly stopped hearing chatter . Did this on all 8 passenger bank
Then I shut the truck off and ran 1/4 turn 12 noon to 3pm preload on all 8

Your process sounds good. So if I'm understanding you correctly, the valvetrain is currently
quiet, but the #8 cylinder has no compression?

I did not run 1/2 turn (12-6)
Just a 1/4 turn . It sounded good but had the miss it has had the miss ever since the first random clatter occurred when on my road trip . The truck never missed before that so this miss has been before the adjustment also . The plugs looked horid the cap was crusty so I did all the plug wires cap rotor etc to try and alleviate the miss before I went and did the compression check .

So you have renewed the high voltage side of the ignition. Good to know.

All I know is zero compression is odd it should be low or read something

Are you sure that #8 has zero compression? What I mean is that if your
compression gauge managed to inhale a piece of grit in all the excitement
before you did #8 cylinder (and it was the last one you did) then maybe
we're getting this weird result because of the test gear, and not the state
of that cylinder? If you could verify that the compression tester is still
working on 1 of the previously good cylinders that would help to eliminate
this possibility.

So that’s what I attest it to the nut adjustment maybe !

The thing that you read elsewhere regarding low vs no compression. For example,
if you had weak/worn piston rings or a valve seat starting to burn, then you might
get a 40 or 60 psi reading. But when the valve preload is accidentally set too deep,
this bottoms out the pushrod plunger, and further tightening starts opening the
valve up. And having a valve hung open will indeed give you a true zero compression reading.

****

So there you have it. Prove that the compression tester gauge is still working
properly by using it on a known-good cylinder, and if it is reporting reliable
readings, then go ahead and recheck the #8 cylinder rocker arm settings.
And be sure to count many turns it takes to get the lifters clacking.
(1/4 turn, 1/2 turn...1 1/2 turns, etc)

EDIT: When you pull the #8 spark plug, how does it look? Normal? Or wet
with fuel? Or worse? If it looks anything other than perfect, then take a
sharp photo of that & post it along with your other observations.

 

[A97obs]

I backed the rocker nuts back off until Clatter came back and I got 150psi back and smooth idle .
So it was the valves open.
But I don’t know where I went wrong initially. I quieted the chatter , and shut the truck off and did 1/4 turn preload that’s where I lost compression. Maybe it was a hair to much

 

[A97obs]

Your process sounds good. So if I'm understanding you correctly, the valvetrain is currently
quiet, but the #8 cylinder has no compression?



So you have renewed the high voltage side of the ignition. Good to know.



Are you sure that #8 has zero compression? What I mean is that if your
compression gauge managed to inhale a piece of grit in all the excitement
before you did #8 cylinder (and it was the last one you did) then maybe
we're getting this weird result because of the test gear, and not the state
of that cylinder? If you could verify that the compression tester is still
working on 1 of the previously good cylinders that would help to eliminate
this possibility.





The thing that you read elsewhere regarding low vs no compression. For example,
if you had weak/worn piston rings or a valve seat starting to burn, then you might
get a 40 or 60 psi reading. But when the valve preload is accidentally set too deep,
this bottoms out the pushrod plunger, and further tightening starts opening the
valve up. And having the valve open will indeed give you a zero compression reading.

****

So there you have it. Prove that the compression tester gauge is still working
properly by using it on a known-good cylinder, and if it is reporting reliable
readings, then go ahead and recheck the #8 cylinder rocker arm settings.
And be sure to count many turns it takes to get the lifters clacking.
(1/4 turn, 1/2 turn...1 1/2 turns, etc)

EDIT: When you pull the #8 spark plug, how does it look? Normal? Or wet
with fuel? Or worse? If it looks anything other than perfect, then take a
sharp photo of that & post it along with your other observations.

You must be registered for see images attach

These were the OLD plugs not the new ones prior to me changing them today
8,6,4,2 from left to right

Cylinder 2 was really white and seemed lean ?
But I did new plugs wires rotor and cap after the fact

 

[scott2093]

I backed the rocker nuts back off until Clatter came back and I got 150psi back and smooth idle .
So it was the valves open.
But I don’t know where I went wrong initially. I quoted the chatter , and shut the truck off and did 1/4 turn preload that’s where I lost compression. Maybe it was a hair to much

did you count the number of turns until it clattered?

 

[A97obs]

did you count the number of turns until it clattered?

Yes it was 1/4 turn back from 3 to noon just as the initial setting was
From 12-3 position on the ratchet .

For Some reason the compression came back and from there I clockwised the turns again until it stopped making noise super slowly 10second in between turns for catch up - I don’t do huge turns super super small turns for the lash and to ( hear) each rocker quiet down to nothing so small of turns can’t even give them a count . I only do the pre load as a counted turns .

It’s running great now smooth power no noises new wires plugs which were needed two of the cap terminals were corroded The rotor points looked burnt up .
It needed the tune up besides the valve adjustment.
At least i know i got a good bottom end making the top end worth a rebuild if i ever need a new cam and lifters or power adders

 

[scott2093]

Yes it was 1/4 turn back from 3 to noon just as the initial setting was

I really loved the way 1/4 to 1/2 turn felt in my truck but I'd get random longer lasting tapping at startup that I couldn't get to stop until I went down to a full turn. I know my lifters were preloaded at at least 1.5 turns before I ever messed with them but couldn't tell you why.
Don't know what lifters are in and, looking around on some forums, some rollers (I have rollers in my 93 crate motor) were talking about 2 turns..jeez..

I still get a couple of slaps every now and then at startup but, I don't really want to go past where I'm at to stop it which I'm pretty sure would. Actually thinking about trying again for 1/2 turn just so I can revisit the feeling of less preload but, for some reason, I'd get more startup taps..

Hmmm..reminds me that I meant to revisit my oil filter adapter housing since I missed a step cleaning it last time....

Glad you're having success.. Keep us updated on how it goes....

 

[Erik the Awful]

Maybe one of the lifters on #8 isn't pumping up, giving you a tighter window of adjustment?