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Unhappy stuck valve??

I was doing a valve adjustment and no matter how loose i turn the screw theres no gap. Its on the 3rd cyl and i belive its the intake(outer valve, the exaust valve checks ok. theres no movment in the arm. i triple check to make sure it was on the 3 cyl cycle. any ideas what may be the problem? the car runs but its rough and likes to backfire a lot. thanks
Old 10-14-2001, 09:51 AM
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sounds like a dropped valve seat that has jammed the valve...
Old 10-14-2001, 10:00 AM
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how would you go about rapairing that?
Old 10-14-2001, 10:06 AM
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I assume you having some one turning the motor by hand you are watching the movement.

Just double check that you are truely on #3 Cyclinder. I would not run the car until I had that problem corrected.

Typically, one must remove the head to fix the problem if it is a drop guide.

Good luck.
Old 10-14-2001, 10:37 AM
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well i checked again and its on the 3 cyl I took the adj screw completly out and the rocker arm is just frozen there, its not backing out. I checked for blockage of the arm but there was nothing. Also should there be gaps in any other valves? i noticed when i did number 1 i could also check the gap in number 2, and when its on the 3rd cyl i can also check the gaps for number 4.i do however check them when there cylinder is at tdc, not by the way i before mentioned. call me a dumby, but am i checking these right, and could there be a problem with the rocker arm?
Old 10-14-2001, 11:23 AM
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Pull the rocker arm assembly....and the get a spring compressor. Check the actuation of the valve....no movement equals stuck valve, most likely the seat.

Another more likely check....do a compression check.

I'm assuming the engine still spins from your previous post, 0 compression on number 3 will tell you that you have serious problems that no amount of in car engine diagnostics will cure.

Sounds like top end tear down time. Just in time for Winter....you didn't have anything else to do, right?

[This message has been edited by mikez (edited 10-14-2001).]
Old 10-14-2001, 11:40 AM
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(chuckle) hopefully its not a long winter, thanks for the input, it looks like i have my work cut out for me. weres a good sledge hammer when you need one.....
Old 10-14-2001, 11:56 AM
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jis042,

From your second to last post i think you have made a mistake.

You can only do one cyl at a time. You can't do both cyls. on the same side at the same time.

You can do 1/3 and 2/4 at the same time. Well, maybe on a 1.7 you can at least my 1.7 i can but i couldnt get it to work on my 2.0. Try this link: http://www.pelicanparts.com/techarticles/914_valve_adjust/914_valve_adjust.htm

Oh ya, is your push rod in the 'cup' on the rocker? that can cause some adjustment probs.
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[This message has been edited by Conrad W Peden (edited 10-14-2001).]
Old 10-14-2001, 12:57 PM
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the cylinders are right. i have the original markings on the fan belt and the distributor rotor is in all the correct spots. when you check the cylinder there should be a gap between the adj screw and the valve stem right, and thats what you measure ? well like i said when its in tdc for cyl 1 there is also gaps in cyl 2 and so forth. its a 71-1.7.
Old 10-15-2001, 03:49 PM
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When you set the gaps for cyl. 1 you can only set the gaps for cyl. 3 at the same time. See this link for the relationship on the engine between cyl. 1/3 and 2/4 also thier relationship to the flywheel, note driving direction.

http://www.pelicanparts.com/techarticles/914_valve_adjust/914_valve_adjust_pic22_big.J PG

Cylinder 1 and 2 are on the same side and can't be set at the same time. If you try to there will definitly be problems. The cyl numbers are also on the engine tin.

Do you have a Haynes manual or something comparable? If not, try setting the valves according to the article that i quoted in my last post and let me know what you find.

BTW... A compression test with improperly adjusted valves will tell you nothing.

My 1.7 went from 15 lbs to 145 lbs on the "dead" cyl. after I adjusted the valves properly.

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73 914 L20E 2.0L in resto.
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[This message has been edited by Conrad W Peden (edited 10-15-2001).]
Old 10-15-2001, 06:29 PM
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Aye i have a hanes manual, and i've read those tech articles too. I dont adjust the valves until there piston is at tdc(checked by markings and distributor rotor), one at a time. but the valves seem to be open at the same time for 1 and 2, and then 3 and 4. sounds weird i know but thats whats happining. maybe something real screwy is going on?
Old 10-15-2001, 09:03 PM
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Okay, let's work this out here.

Firing order: 1-4-3-2.
Strokes: Intake, Compression, Power, Exhaust.
During the Intake stroke, the Intake valve is open. During the Compression stroke, both valves are closed. During the Power stroke, both valves are closed. During the Exhaust stroke, the exhaust valve is open.

TDC is between Compression and Power strokes.

So, when #1 is at TDC, #4 is midway between Power and Exhaust strokes, and the exhaust valve is just starting to open. #3 is midway between Exhaust and Intake strokes, so both valves may be open a bit. (This is "overlap".) #2 is midway between Intake and Compression strokes, so the intake valve may be open a bit.

Is this what you're seeing? If so, then it is normal. Particularly if you've got a "lumpy" carb-oriented cam.

--DD

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Old 10-16-2001, 06:16 AM
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Okay...quick question. I have always rotated the engine to each cylinder tdc checked on the flywheel and the dizzy. Can I stop doing this and just adjust 1 & 3 at the same point. I was always worried that the cam may be doing strange things on the other side. Can someone either quell my fears or tell me the extra work is worth it!!!
TIA
JB
Old 10-16-2001, 07:45 AM
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I have heard that adj 2 sets of valves @ the same time on a type IV engine can lead to burnt valves.
Old 10-16-2001, 11:16 AM
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Probably not the case but Ive found that if youre not careful when installing the rocker arm the pushrod can fall out of the divet in the lifter. This causes the symptom you described-inability to adjust the valves b/c everything is too tight. Now if you didnt loosen the rocker arm, I dont think this would happen. My solution is to loosen the rocker arms from the head and gently pry the push rod up with a screwdriver.
Old 10-16-2001, 11:39 AM
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JB, there are two methods used for adjusting the valves. Neither one lets you adjust both valves of more than one cylinder at the same time.

If you use the "TDC method" (which is outlined in the factory manual and elsewhere), there will be exactly one cylinder that is at TDC between compression and power strokes. You adjust both valves on that one cylinder. This is the method I use.

Tom Wilson outlines another method in his VW rebuild book. The short version is that you rotate the engine until you see a valve rocking, then you adjust that same valve on the other side of the engine. In other words, if the exhaust valve of the front-left cylinder is open, you can adjust the exhaust valve of the front-right cylinder.

You never, ever want to adjust the clearance on a valve while the other valve on that cylinder is open. Ever. On three different motors I have checked, and at least two others that I have talked to someone about, this results in incorrect valve settings. (They come out narrower than you set.)

--DD

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Old 10-16-2001, 02:19 PM
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Thanks Dave!

I was wondering why i couldnt get the 2.0 to adjust properly. I kept going around in circles.

I would adjust 1 and 3 then turn the crank 180 and do 2/4. Turn the crank and number 1 is out by too much too count.

Thats probably why the 1.7 runs so SH%$#Y right now too. That and worn out adjusters.

The 2.0 is still on the bench and hasnt run yet still have to put the resto back together. Slowly but surely. Nah, just slowly.

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73 914 L20E 2.0L in resto.
a914lover73@hotmail.com

[This message has been edited by Conrad W Peden (edited 10-16-2001).]
Old 10-16-2001, 04:15 PM
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That problem sounds very strange. When I dropped a seat and had a stuck valve, I always had too much clearence at TDC. In fact that's how I knew something was up with the valves. You are describing no clearence and the spring still in compression at TDC. Dropped seats or bent valves can't make the stem push out further, can they? Maybe if the seat falls below the head of the valve and then come back up. Is that possible? Anyone know?

Pull the rockers as mikeZ suggests, it's really easy to do. If no problems you might risk a compression check and hope cranking it over doesn't do further damage.
Old 10-16-2001, 04:51 PM
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sometimes the seat gets loose and burrows further into the head. when the related rocker set is off, see if the spring retainer on that valve sits higher than the rest. a compression check should show some evidence of that problem.
Old 10-16-2001, 05:40 PM
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Aye i'm going to do a compression check tomarrow hopefully. i finally got another day off to work on it.be interesting to see how it checks out, and the rockers too.
Old 10-17-2001, 07:11 AM
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