2000 5.7 GS Low Compression

[300sflyer]

Re: 2000 5.7 GS Low Compression

The head is back on, and my compression is normal again. Well sort of...

I am having an issue setting the valve lash though... I am following the procedure in the Volvo manual, and all is good until I tighten each valve one additional turn. At that point, I loose compression in all 4 cylinders... Can't understand why.. I have done this dozens of times before on other engines with no issue.

With the engine at TDC and the #1 cylinder on compression, I tighten the correct 4 valves until all the lash is gone, and you can still spin the pushrod quite easily with 2 fingers. If I begin to back it off, I can then feel the beginnings of movement up and down. I then spin the crank 360, and do the same thing to the remaining 4 valves. If I leave it like that, I get 180-190 in all 4 cylinders. If I tighten each valve one more turn as stated in the manual, I get zero compression in all 4 cylinders.

Not sure why???

 

[Bondo]

Re: 2000 5.7 GS Low Compression

The head is back on, and my compression is normal again. Well sort of...

I am having an issue setting the valve lash though... I am following the procedure in the Volvo manual, and all is good until I tighten each valve one additional turn. At that point, I loose compression in all 4 cylinders... Can't understand why.. I have done this dozens of times before on other engines with no issue.

With the engine at TDC and the #1 cylinder on compression, I tighten the correct 4 valves until all the lash is gone, and you can still spin the pushrod quite easily with 2 fingers. If I begin to back it off, I can then feel the beginnings of movement up and down. I then spin the crank 360, and do the same thing to the remaining 4 valves. If I leave it like that, I get 180-190 in all 4 cylinders. If I tighten each valve one more turn as stated in the manual, I get zero compression in all 4 cylinders.

Not sure why???

Ayuh,.... Donno 'bout yer manual, but I tighten 1/2 turn, after the lash is zero,....

 

[300sflyer]

Re: 2000 5.7 GS Low Compression

Ayuh,.... Donno 'bout yer manual, but I tighten 1/2 turn, after the lash is zero,....

I may try that...

Here are the instructions from the manual:

3. With engine assembly in number 1 cylinder firing position, following
valves can be adjusted.
? Exhaust 1, 3, 4, 8
? Intake 1, 2, 5, 7
1 4. Back off valve rocker arm nut until lash is felt in valve push rod.
Then tighten valve rocker arm nut until all lash is removed. Zero lash
can be felt by moving valve push rod up and down between thumb and
forefinger until there is no more movement.
5. When all free play has been removed, tighten valve rocker arm nut
one additional turn (360 degrees).
6. Turn crankshaft one revolution until hub arrow is again at 12 o’clock
position. This is number 6 cylinder firing position. Following valves can
now be adjusted:
? Exhaust 2, 5, 6, 7
? Intake 3, 4, 6, 8

 

[Bondo]

Re: 2000 5.7 GS Low Compression

I may try that...

Here are the instructions from the manual:

3. With engine assembly in number 1 cylinder firing position, following
valves can be adjusted.
• Exhaust 1, 3, 4, 8
• Intake 1, 2, 5, 7
1 4. Back off valve rocker arm nut until lash is felt in valve push rod.
Then tighten valve rocker arm nut until all lash is removed. Zero lash
can be felt by moving valve push rod up and down between thumb and
forefinger until there is no more movement.
5. When all free play has been removed, tighten valve rocker arm nut
one additional turn (360 degrees).
6. Turn crankshaft one revolution until hub arrow is again at 12 o’clock
position. This is number 6 cylinder firing position. Following valves can
now be adjusted:
• Exhaust 2, 5, 6, 7
• Intake 3, 4, 6, 8

Ayuh,.... That's better instructions than some,.... other than the 360?, 1 full turn,...

I hate when turnin' the pushrod is used to find zero lash,...
Lash is up/ down movement, not rotational,...

As I said, I find zero lash, 'n go 1/2 turn tighter, never more than 3/4 turn,...

Or,... Fire it up, 'n adjust 'em dynamically,....

Loosen 'em til they rattle, turn down to no rattle, then another 1/2 turn,...

 

[Silvertip]

Re: 2000 5.7 GS Low Compression

Wasn't it DON that always included the statement:

Why is it there is never time to do it right the first time but always enough time to do the job over again? (Or words to that effect!) And those words ring true in every respect when trying to remove a head without removing the manifold. There are locating pins in the block that locate the head during installation. The head must be raised far enough to clear those pins. Raising the head that far means the manifold must also be raised that far which could break the ears on the other side through which the bolts holding that side of the manifold to the head. Sealing up the ends of the manifold is then another issue during assembly. It simply is not worth the trouble and if you can't get the manifold off in another 1/2 hour you need professional help (in the form of a mechanic). Do it right and save time, frustration and money in the long run.

 

[300sflyer]

Re: 2000 5.7 GS Low Compression

Wasn't it DON that always included the statement:

Why is it there is never time to do it right the first time but always enough time to do the job over again? (Or words to that effect!) And those words ring true in every respect when trying to remove a head without removing the manifold. There are locating pins in the block that locate the head during installation. The head must be raised far enough to clear those pins. Raising the head that far means the manifold must also be raised that far which could break the ears on the other side through which the bolts holding that side of the manifold to the head. Sealing up the ends of the manifold is then another issue during assembly. It simply is not worth the trouble and if you can't get the manifold off in another 1/2 hour you need professional help (in the form of a mechanic). Do it right and save time, frustration and money in the long run.

As stated in post #19, I removed the intake, before removing the head.

 

[300sflyer]

Re: 2000 5.7 GS Low Compression

Found this post about adjusting valves from Don S back in 2011.

"THERE is where everyone gets in trouble when following the instructions.
When you are moving the pushrod and tightening down the rocker arm nut, you tighten it down until it just stops the movement of the pushrod. That's it for zero lash, you do not do it again you dont move the pushrod again, because it will move. You stop the push rod one time and one time only. Then turn the rocker nut down either 3/4 or 1 turn what ever YOUR manual says, and then you are done with that lifter and you move on to the next.
Now, if you have any problems with the lifters being too tight or too loose, then you need new lifters or attempt to rebuild your lifters. Because there is a problem with them."

I am going to recheck them next week.

I have a feeling Don is still going to be helping folks like me for years to come! Thank you Don!

 

[300sflyer]

Re: 2000 5.7 GS Low Compression

Rechecked the valve lash very carefully, and ended up at 1/2 turn. Engine runs fine again. Now I just have to wait 5 months to try it out on the water. LOL!