Hydraulic Valve Adjustment and Associated Noise - kinda long

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Strop
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Hydraulic Valve Adjustment and Associated Noise - kinda long

Post by Strop » Mon Jun 18, 2007 11:24 am

Not happy with the fact that my my 82 Vanagon idle was erratic and I had low vacuum readings of 12-13 at idle (I have a vacuum gauge installed on my dash) I decided that I better check my compression.

So, I did a compression check and got low readings on cylinders 1 and 3 (30 and 50 to be exact). 2 and 4 were about 135.

Now , this engine has new pistons, rings, cylinders, lifters, and rebuilt heads with new exhaust valves - so I did not think that the low compression was due to rings.

Once the engine was running quietly - I assume that this would indicate that the lifters were sufficiently pumped up - I shut it down and waited for it to cool just enough so I could work with it . I started with number 1 and took the adjusting nut and screw completely off to inspect and clean them. Then I finger tightened the screw until i could just feel it touch the valve stem and then tightened the screw 1.5 turns. Then I tightened the locknut - making certain that the screw did not deviate from the 1.5 position. Then I checked the compression which read about 30. This pissed me off so I then backed the screw out .5 to 1 full turn and the compression went up to 60. Then another .5 turn to .5 and I am now at 120. Then to 1/4 turn still at 120. Then to zero lash and I get 145.

So, I left it there and did the other offending cylinder number 3. Exactly the same thing. So I did the same there, put everything back together and fired it up.

The engine started quicker, the vacuum reading on my gauge is now a 16-17, and the gas pedal feels somewhat firmer as I depress it (maybe this is my imagination), and the idle is not as jumpy as before it still is but I believe i have an elusive vacuum leak somewhere.

However, the engine is now clacking away like a typewriter and will not subside - even after a good 45 minute drive.

From all of my reading about VW engines (and I assume this would apply to any engine) the engine is now operating better as the compession and vacuum are now where they should be. However, what damage am I doing to the valve train in accomplishing this?

Do I tighten the valves up a bit to achieve a "happy medium" or just run around with my new IBM Selectric engine?

Could there be an issue with the push rods on the offending cylinders?

Any and all thoughts appreciated.

Regards,

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Sean Gallagher
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Post by Sean Gallagher » Mon Jun 18, 2007 4:36 pm

We need Don, (vw lover), from North Canton to weigh in on the hydraulic lifter qustion. Don touched on some of the issues he ran into with his lifters on his "still runs like crap" thread. I think he is on vacation now. Hopefully, he will read the thread and post.
1957 Oval (36HP 6 volt)
1959 SO-23 Westfalia (36HP 6 volt)
1978 Kombi (6 volts too many!)

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Amskeptic
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Re: Hydraulic Valve Adjustment and Associated Noise - kinda

Post by Amskeptic » Mon Jun 18, 2007 6:11 pm

Strop wrote: got low readings on cylinders 1 and 3
I checked the compression which read about 30. This pissed me off so I then backed the screw out .5 to 1 full turn and the compression went up to 60. Then another .5 turn to .5 and I am now at 120. Then to 1/4 turn still at 120. Then to zero lash and I get 145.

the engine is now clacking away like a typewriter and will not subside - even after a good 45 minute drive.
What you did originally was this:
When you preloaded the lifters 1 1/2 turns, instead of watching the pushrod slowly push down into the lifter as you cranked on the screw, you opened your valve. This is the fault of the lifter not allowing the plunger to go down. You can try to see if the lifter will properly take in the pushrod as you crank on the screw, but if it refuses, you need to investigate why. A stuck check valve could do this. Or, the lifter is just very slow to compress. Are the screws really down into the rocker arm when you preload? This can be evidence that the plunger is already all the way down in the lifter, and your "preload" just opened the valve. If you have questions, pull the lifter and make sure the plunger is up against the circlip when it is out of the engine. It is ALL fun.
Colin
BobD - 1978 Bus . . . . . . . . . . . 112,660 miles
Chloe - 1970 bus . . . . . . . . . . . 206,845 miles
Naranja - 1977 Westfalia . . . . . 112,885 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,899 miles

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Re: Hydraulic Valve Adjustment and Associated Noise - kinda

Post by Strop » Mon Jun 18, 2007 6:25 pm

Amskeptic wrote:
Strop wrote: got low readings on cylinders 1 and 3
I checked the compression which read about 30. This pissed me off so I then backed the screw out .5 to 1 full turn and the compression went up to 60. Then another .5 turn to .5 and I am now at 120. Then to 1/4 turn still at 120. Then to zero lash and I get 145.

the engine is now clacking away like a typewriter and will not subside - even after a good 45 minute drive.
What you did originally was this:
When you preloaded the lifters 1 1/2 turns, instead of watching the pushrod slowly push down into the lifter as you cranked on the screw, you opened your valve. This is the fault of the lifter not allowing the plunger to go down. You can try to see if the lifter will properly take in the pushrod as you crank on the screw, but if it refuses, you need to investigate why. A stuck check valve could do this. Or, the lifter is just very slow to compress. Are the screws really down into the rocker arm when you preload? This can be evidence that the plunger is already all the way down in the lifter, and your "preload" just opened the valve. If you have questions, pull the lifter and make sure the plunger is up against the circlip when it is out of the engine. It is ALL fun.
Colin
Regarding the screws - they are not buried in the rocker arm. When they are turned in 2 turns they look to be sticking out about the same amount as the working valves.

Seems odd to me that I would have 4 bad lifters. Could there be a problem with the pushrods not being seated in the lifter properly?

If the lifter is all pumped up how would turning the screw make the lifter compress? Wouldn't the valve HAVE to open since the lifter is now rock solid?

Maybe I am missing something here...... :geek:

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Re: Hydraulic Valve Adjustment and Associated Noise - kinda

Post by Amskeptic » Mon Jun 18, 2007 6:30 pm

Strop wrote: Seems odd to me that I would have 4 bad lifters.
Only takes two, Strop, to ruin two cylinders' compression readings. . .
Strop wrote: Could there be a problem with the pushrods not being seated in the lifter properly?
Good thinking, keep searching. TDC your problem cylinders, back off the screws entirely, rotate the pushrods with your fingers, tight fit but doable, and lift the pushrod at the bottom of the tube with a small flat-bladed screwdriver while rotating and pushing the pushrod. You'll feel it sort of click/give/pop down into the socket. Don't let it happen again.
Colin :pirate:
BobD - 1978 Bus . . . . . . . . . . . 112,660 miles
Chloe - 1970 bus . . . . . . . . . . . 206,845 miles
Naranja - 1977 Westfalia . . . . . 112,885 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,899 miles

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Strop
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Post by Strop » Tue Jun 19, 2007 4:14 am

Colin,

What about the lifter being pumped up and solid? How would it compress instead of the valve moving? Does it somehow still compress when it is solid?

thx

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Post by Amskeptic » Wed Jun 20, 2007 7:46 am

Strop wrote:Colin,

What about the lifter being pumped up and solid? How would it compress instead of the valve moving? Does it somehow still compress when it is solid?

thx
That is just it. If the lifter refuses to compress in let's say 5 minutes, it will burn up your valve in the engine. The valve train expands over the course of five minutes as the engine warms up, the lifter has to give or the valve won't close. The only way to know what is going on is to test it. At TDC, turn in the screw until you see the valve open. Come back in 10 minutes and the valve had best be closed. Then release the screw quickly until you have a little clack. Wait another 5 minutes. The clack had best be gone. The plunger must be mobile as we play with the screw. The lifter only needs to be solid when engine oil pressure is acting on it, i.e. the engine is running.
Colin
BobD - 1978 Bus . . . . . . . . . . . 112,660 miles
Chloe - 1970 bus . . . . . . . . . . . 206,845 miles
Naranja - 1977 Westfalia . . . . . 112,885 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,899 miles

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Strop
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Post by Strop » Wed Jun 20, 2007 8:33 am

I turned the adjuster screws in another 1/4 turn and let the engine run and they quieted down significantly after about 20 minutes. The idle is still pretty stable with an intermittent 300 RPM flutter on either side of 900.

The manifold vacuum at cold idle is about 15, then when warm is around 17 - 18.

Did not check compression again, but I am assuming that it is still OK as the vacuum is good.

Filled er up last night to see how many miles I could get before the needle went below the full line on the gas gauge, I got about 30 miles - when before I got about 14.

Based on all of this I am assuming that all of the valves are now closing OK as the vacuum is so good and stable.

The only thing I still hear is some valve train clatter once the engine gets good and hot.

Appreciate the good advice - most helpful. =D>

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Post by Amskeptic » Wed Jun 20, 2007 4:52 pm

Strop wrote:I turned the adjuster screws in another 1/4 turn and let the engine run and they quieted down significantly after about 20 minutes. Appreciate the good advice - most helpful. =D>
Give us an update when you summon the courage to preload the lifters to a genuine 1 1/2 turns down from a guaranteed-all-the-way up. If you leave the plungers too close to the top, the circlips will get beaten to death and disassemble your lifters in-situe. The tip-off will be the next time you try to find 0 lash, you will never obtain it even when you unscrew the adjuster screw pretty much all the way out of the rocker arm. That means Pull The Push Rod Tube and extract the pieces of lifter guts with an eye on not letting any parts fall into the crankcase.
Colin
BobD - 1978 Bus . . . . . . . . . . . 112,660 miles
Chloe - 1970 bus . . . . . . . . . . . 206,845 miles
Naranja - 1977 Westfalia . . . . . 112,885 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,899 miles

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Strop
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Post by Strop » Thu Jun 21, 2007 4:15 am

Amskeptic wrote:
Strop wrote:I turned the adjuster screws in another 1/4 turn and let the engine run and they quieted down significantly after about 20 minutes. Appreciate the good advice - most helpful. =D>
Give us an update when you summon the courage to preload the lifters to a genuine 1 1/2 turns down from a guaranteed-all-the-way up. If you leave the plungers too close to the top, the circlips will get beaten to death and disassemble your lifters in-situe. The tip-off will be the next time you try to find 0 lash, you will never obtain it even when you unscrew the adjuster screw pretty much all the way out of the rocker arm. That means Pull The Push Rod Tube and extract the pieces of lifter guts with an eye on not letting any parts fall into the crankcase.
Colin
Would the circlips getting beat to death account for any type of noise or is it pretty much a silent death?

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Post by Amskeptic » Thu Jun 21, 2007 2:06 pm

Strop wrote: Would the circlips getting beat to death account for any type of noise or is it pretty much a silent death?
I have only happened across such catastrophes well after the fact.
I live with coughcoughsupERior, cough solid lifters. . . .
Colin
BobD - 1978 Bus . . . . . . . . . . . 112,660 miles
Chloe - 1970 bus . . . . . . . . . . . 206,845 miles
Naranja - 1977 Westfalia . . . . . 112,885 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,899 miles

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Strop
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Post by Strop » Fri Jun 22, 2007 9:03 pm

After all of this I can see why folks might like solid lifters....I think I would rather haver them as I am the type of person who likes to be forced into maintenance mode where I can see any damage as it is occurring. Sure, the hydraulics are nice with regards to maintenance, but I would rather have the maintenance. I will be turning the screws in another 1/2 tomorrow. I am still having a clicking sound in the valve train, but I dont think it is the hydraulic lifters not being pumped up - gotta be due to bad adjustment.

Since I already know where my affected cylinders are set with regards to amount of turns - there is no problem with just popping the valve covers off and turning the adjusters in another 1/2 turn - without having the pistons set to TDC is there? Another 1/2 turn is a 1/2 turn regardless correct? Am I missing something?

TIA

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Post by Amskeptic » Sat Jun 23, 2007 7:40 am

Strop wrote: I am still having a clicking sound in the valve train, but I dont think it is the hydraulic lifters not being pumped up - gotta be due to bad adjustment.

Since I already know where my affected cylinders are set with regards to amount of turns - there is no problem with just popping the valve covers off and turning the adjusters in another 1/2 turn - without having the pistons set to TDC is there? Am I missing something?

TIA
Some clicks are actually cracked exhaust ports, thought you should know. Sounds just like a valve, but gets a little louder under load.

Yes. You are missing something. 168# of valve spring pressure is not nice to the adjuster screws. Don't be lazy. I did not raise you to be a slouch.
Mom
BobD - 1978 Bus . . . . . . . . . . . 112,660 miles
Chloe - 1970 bus . . . . . . . . . . . 206,845 miles
Naranja - 1977 Westfalia . . . . . 112,885 miles
Pluck - 1973 Squareback . . . . . . 55,570 miles
Alexus - 1991 Lexus LS400 . . . 78,899 miles

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Strop
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Post by Strop » Mon Jul 02, 2007 7:31 am

Are there different variations with regards to valve springs? I wonder if the rebuilder fubar'd and put a couple of wrong springs in there and that is why the valves are opening as soon as I turn the adjuster in excess of zero lash.

The lifters are definitely pumped up hard when I am doing the adjustment.

I am definitely at the correct valve and at TDC

I am going to remove the pushrods/lifters tonite and examine and clean - however I am not expecting any issues as they are all new. I guess it is "possible" that the pushrods have slipped from the cups on the lifters, but I really doubt it.

Yesterday I set them to zero and figured I would go for a drive and maybe the problem would correct itself by some divine act of god or something.

When I do this the vacuum /compression reading is good, but the engine still has some of that pumping sound - it does not sound correct and I am assuming that this is due to insufficient lift as a result of the wrong adjustment setting. The lifters are quiet though - until it gets warmed up - then it sounds like a IBM Selectric and never stops.

Gotta figure out why that valve is opening when I do the preload.....

Ahhhhhhhhh...........................

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Strop
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Post by Strop » Mon Jul 02, 2007 11:15 am

Just checked number 3:

turned both in at TDC after 5 minutes or so the "inside" valve expanded and I could finger loosen the adjuster screw

The "outside" valve did nothing and is still tight.

So, the spring is shot or my new lifter is clogged, or the pushrod has slipped.

What else could it be?



Amskeptic wrote:
Strop wrote:Colin,

What about the lifter being pumped up and solid? How would it compress instead of the valve moving? Does it somehow still compress when it is solid?

thx
That is just it. If the lifter refuses to compress in let's say 5 minutes, it will burn up your valve in the engine. The valve train expands over the course of five minutes as the engine warms up, the lifter has to give or the valve won't close. The only way to know what is going on is to test it. At TDC, turn in the screw until you see the valve open. Come back in 10 minutes and the valve had best be closed. Then release the screw quickly until you have a little clack. Wait another 5 minutes. The clack had best be gone. The plunger must be mobile as we play with the screw. The lifter only needs to be solid when engine oil pressure is acting on it, i.e. the engine is running.
Colin

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