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79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
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Posted: Wed Nov 08, 2017 5:48 pm Post subject: Sticky valve - random occurrence or harbinger of future trouble? |
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No recent threads on this when I searched, so here is my question:
I tune up my '64 1200 stock engine twice a year. Change the oil, adjust the valves, timing, dwell gap, etc. I only put about 2,000 miles on it a year. Never a problem, always routine. Engine runs well, no problems.
The car had sat for about 10 days without running. The weather had been cool on and off. I didn't run the engine before starting the tune up. But everything went just as it had every other tune up, until got to Number 4 intake valve, and found it was not loose for me to adjust.
I rotated the crank all the way around again, and still not loose. The number 4 exhaust rocker was loose both times to adjust. The last time I turned the crankshaft fully around, the intake rocker arm clearly showed it was in the lowered position for intake into the cylinder, and not in the same position as the exhaust rocker arm.
I gently tapped on the valve spring with a hammer, and turned the crankshaft again. This time, the rocker was loose and ready for adjustment. I finished up, started it, thought I heard some high pitched tapping, but couldn't be sure it wasn't my imagination. I drove it a few miles, and heard nothing and felt nothing that seemed wrong.
So was this just a random occurrence? Or am I in store for trouble in the near future? _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt.
Last edited by 79SuperVert on Thu Nov 09, 2017 6:20 am; edited 1 time in total |
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Pruneman99 Samba Member
Joined: February 22, 2012 Posts: 5013 Location: Oceanside
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Posted: Wed Nov 08, 2017 6:11 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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Could be trouble, maybe not.
Does your fuel have a bunch of ethonol? It can make a sticky varnish that can stick intake valves if it sits awhile.
Could be a cracked/broken spring.
Could be a bit of debris that got caught in the guide.
Can you see the guide end and notice if it's wearing funny/crooked? |
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79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
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Posted: Wed Nov 08, 2017 7:28 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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Our gas is not more than 10% ethanol. Don't know if it matters for varnish, but I use a fuel "drier" (Sta-Bil) in every tank.
Can't tell if the spring is cracked. Didn't look out of the ordinary. But a cracked or broken spring would show itself by rough running, wouldn't it?
Couldn't see the guide end from the position I was in to adjust the valves. No debris in the oil or screen.
Since I'm not about to pull the engine, I guess I will wait until the next valve adjustment in the spring and see if there is a similar problem, and in the meantime drive it a few miles a week like I usually do. Nothing lasts forever, but I figured with frequent regular oil changes and maintenance I was maximizing my engine's life. So this is a surprise. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
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panicman Samba Member
Joined: December 18, 2011 Posts: 2290 Location: Canby, OR
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Posted: Wed Nov 08, 2017 8:30 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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Don’t forget to update this thread!!
I’ll be waiting... and eating popcorn... _________________ Plate of shrimp |
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61SNRF Samba Member
Joined: March 29, 2009 Posts: 4657 Location: Whittier 90602
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Posted: Wed Nov 08, 2017 8:32 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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If a valve "sticks" in its guide, and therefore stays open when it should be closed, then you would have more than normal clearance when you go to adjust.
So, if you say the valve was tight with no clearance, that would mean most likely the rocker arm is sticking on the shaft. Rockers are last in a long line for oil feed. I have seen rocker shafts and bushings gauled from oil starvation.
Being a hobby car is not as an easy life as in long periods of storage the oil can run off or be thin on cold starts, and seasonal short trips in town cause slugging.
Modern fuels probably don't help as they ultimately dilute oil supply.
If you're sure of the engines history as being sound, then maybe some Marvel Mystery Oil in the fuel tank and a long highway drive.
Then let it cool overnight and recheck to see if adjustment has remained stable. _________________ -Bruce
An ounce of prevention is worth a pound of cure.
Last edited by 61SNRF on Wed Nov 08, 2017 8:34 pm; edited 1 time in total |
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mukluk Samba Member
Joined: October 18, 2012 Posts: 7028 Location: Clyde, TX
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Posted: Wed Nov 08, 2017 8:33 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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Did you try pushing on the rocker arm? If it was the valve that was stuck or a problem with the valve spring, the rocker arm should have moved freely away from the valve stem and thus open up the lash gap. Conversely, if the rocker couldn't be moved away from the valve stem, then the sticking problem would be most likely due to either the rocker arm binding or the lifter sticking in its bore. _________________ 1960 Ragtop w/Semaphores "Inga" |
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79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
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Posted: Thu Nov 09, 2017 6:19 am Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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At the point where both the intake and exhaust rockers should have moved when I pushed on them, the intake rocker would not move. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
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herbie1200 Samba Member
Joined: April 27, 2006 Posts: 833 Location: Rome - Italy
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Posted: Thu Nov 09, 2017 6:43 am Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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If it was my car I will make a rapid check:
Undo the whole rocker arm shaft (n.2 nuts) for check the perfect rocker arm rotation, then check the integrity of push rods.
Finally, try to exchange the investigated push rod with another and verify if the problem has been exchanged. |
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cory464 Samba Member
Joined: November 25, 2010 Posts: 659 Location: kokomo in
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Posted: Thu Nov 09, 2017 11:10 am Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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sounds to me like you have a rocker arm issue. pull the assembly off and inspect. most likely just sticky from not being used, but could be binding from lack of oil, or rust. |
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79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
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Posted: Thu Nov 09, 2017 1:05 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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Thank you for the suggestions. When I get back from vacation, I will do the rocker arm check. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
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bluebus86 Banned
Joined: September 02, 2010 Posts: 11075
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Posted: Thu Nov 09, 2017 7:46 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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if its no longer stuck, Id run it, listening for it sticking again, as that should make a lot of noise I think, plus loss of power, maybe do a few frequent valve gap checks. it could be as stated stuck from excessively long storage, and may be perfectly fine now.
Ggod Luck, Bug On! _________________ Help Prevent VW Engine Fires, see this link.....Engine safety wire information
Stop introducing dirt into your oil when adjusting valves ... https://www.thesamba.com/vw/forum/viewtopic.php?t=683022 |
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Rome Samba Member
Joined: June 02, 2004 Posts: 9653 Location: Pearl River, NY
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Posted: Thu Nov 09, 2017 9:37 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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Joe, my suggestion is to remove the entire rocker assembly. Remove the clip from the #4 end, pull off the washers, wavy washer, #4 exhaust rocker, the mounting block, #4 intake rocker, and washers. Keep the #3 parts on the shaft. Put your #4 intake rocker in a vise with protective jaws, then remove the valve adjusting locknut and the adjusting bolt. Blow through the small oiling holes with carb cleaner spray and the straw (wear goggles) to watch that the cleaner comes out the other end of the holes and are therefore not blocked.
On the exposed rocker shaft, put that into the vise. Get some #400 emery cloth, tear off a strip about an inch wide, then polish the shaft where both of the #4 rockers ride. Of course the section where the #4 intake is the most important one. Polish the shaft by pulling the strip over the shaft like you're polishing your shoes. Only a few pulls back and forth are needed. Loosen the vise and rotate the rocker shaft 1/4 turn, then repeat the polishing. When done, rinse off the shaft carefully with brake cleaner spray. Get any polishing grit out of the grooves where the C clip is attached.
Might as well clean off the entire rocker shaft with the #3 rockers at this point.
Wipe some engine oil onto the polished section of the shaft, and reassemble. Put oil onto the valve adjusting stud and nut also. Rotate both #4 rockers on the shaft fully around; they should both have a nice, even, close feel on the shaft without any "grit" or hindrance after your polishing.
Now look at the #4 intake pushrod. Blow through the center bore (compressed air or carb cleaner with the straw) to make sure it is not blocked, so that oil from the lifters can be pumped through and reach the rocker cup.
Reassemble everything and try the valve adjustment/rocker movement again. Maybe an hour's work total. Let's hope that cures it. |
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79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
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Posted: Sat Nov 11, 2017 2:59 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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Thanks. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
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[email protected] Samba Member
Joined: May 17, 2003 Posts: 4863 Location: Harmony, PA
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Posted: Sun Nov 12, 2017 9:43 am Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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If you take your rocker arms off, lay a straight edge across the valve stems. I've seen performance engines ran with too little spring pressure that loosened seats to the point that they were sinking into the aluminum of the head. Sure, you're not winging your 40 horse past 6k, and exhaust valves/seats usually have issues more often from the heat, but maybe the seat with that valve is sinking allowing the spring to pull the valve through the guide further. If that's the case, monitor the situation EXTREMELY closely, the fuse has been lit. I personally would take the head off for further investigation if that valve was noticeably taller than the others. |
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79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
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Posted: Tue Nov 21, 2017 8:46 am Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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Inspected the driver's side rocker arms yesterday, and #4 intake was loose as it should be for valve adjustment. Took the rocker arm shaft off anyway to see if there was any binding on the rocker arms. All of them seem to move smoothly. Checked the #4 intake push rod and it was straight.
Didn't do any more that day because one of the wavy washers under the retaining nuts disintegrated when I removed the shaft, so I'm getting some new washers. When I get them, I'll decide whether I take the whole thing apart and clean it up, or put it back and check it at the next valve adjustment, after checking to make sure there is no blockage down the push rod tube and that all the valves are at the same height. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
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Zundfolge1432 Samba Member
Joined: June 13, 2004 Posts: 12468
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Posted: Tue Nov 21, 2017 12:05 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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Don't know what washers by themselves would cost I'd wonder if they are good as OE. We used to throw stuff like this in the trash, here's a random bag from under the bench. PM if you need anything else.
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79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
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Posted: Tue Nov 21, 2017 12:33 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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I was surprised that a metal washer would disintegrate the way that one did. I guess the continuous vibration did it. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
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Zundfolge1432 Samba Member
Joined: June 13, 2004 Posts: 12468
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Posted: Tue Nov 21, 2017 1:33 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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79SuperVert wrote: |
I was surprised that a metal washer would disintegrate the way that one did. I guess the continuous vibration did it. |
If you look they always wear at the two high spots that contact solid washer or rocker. We used to take piles of old rockers and break them all down to clean. Then anything that showed excessive wear went into trash. Also had piles of this stuff, too much. So it may not be a bad idea to redo both your rockers and don't forget to look at the adjuster tips. |
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79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
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Posted: Sat Nov 25, 2017 4:14 pm Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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Today I took apart the number 4 rockers, cleaned them, checked the oil holes, oiled the shaft and reassembled them, and then repeated for number 3. After the cleaning and oiling the arms rotated a bit more smoothly than before. Drove it and all seemed OK. In the next couple of days I'll check the valve clearance again. Thanks for all the advice. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
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79SuperVert Samba Member
Joined: May 31, 2002 Posts: 9758 Location: Elizabeth, NJ & La Isla Del Encanto
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Posted: Sun Nov 26, 2017 10:48 am Post subject: Re: Sticky valve - random occurrence or harbinger of future trouble? |
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The plot thickens (or not): today I checked valve clearance on 3 and 4, and found this time that #4 exhaust rocker wouldn't budge (it was #4 intake last time).
Having already taken everything apart and found nothing wrong, I decided that maybe by taking it apart, putting new washers under the securing nuts, and torquing to spec, the geometry changed slightly. So I just readjusted #4 exhaust valve clearance (it took a very small adjustment to restore the clearance), and I will check again in the spring to see what has transpired. I hope it is not a more serious valve problem. _________________ Central Jersey VW Society
Wanted: Art Collins VW (Savannah, Georgia) items - license plate surrounds and other items. Also ivory "AM", "FM" and "SW" buttons for a US Blaupunkt Frankfurt. |
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