Can't adjust valves, or just how badly did I screw up?

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mentalQtip
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Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Thu Jan 02, 2014 9:31 pm

Hi everyone. Very ignorant person here looking for help.
'77 two liter Bus sitting in my garage for a year after putting a picknpull engine in it. While working with the end play and turning the flywheel back and forth I saw the distributor rising up(obviously not fastened down). I quickly turned the flywheel the other way and down it went.
Months later I am finally trying to get it running and find that I can't adjust the valves. The #1 I keep backing the screw out and still can't get any clearance. I'm worried that I really did a bad thing.
Thoughts? Am I screwed? Engine teardown? Just sell it?

Joseph

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Re: Can't adjust valves, or just how badly did I screw up?

Post by vw56oval » Mon Jan 13, 2014 4:59 pm

Check to see that the #1 piston is truly at TDC and start from there.
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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Sat Jan 18, 2014 1:19 am

Thanks for getting back. I understand the idea of bringing the #1 piston to TDC and the valves don't move and the mark on the crank pulley is at zero. The slot in the distributor drive is supposed to be twelve degrees off from parallel to the fan shroud. Is the slot supposed to be offset toward the front or rear of the bus? I'm not sure from the pictures in the bentley.

Thanks

Joseph

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Re: Can't adjust valves, or just how badly did I screw up?

Post by Marc » Sat Jan 18, 2014 3:04 am

The distributor drive position is not a reliable method of determining the camshaft position since it's driven directly off the crank, independent of the camshaft. The pinion needs to be pulled out by more than an inch before it can disengage from the worm gear on the crank, so it wouldn't have skipped any teeth from the slight rise you witnessed and I wouldn't be concerned about that. But to answer the question, the slot should be 12° CCW of parallel to the crankshaft, with the narrower side of the pinion's top in the direction of the left taillight. Since the drive dog on the distributor can be removed and reinstalled 180° away, it's possible to correct for a pinion that's in backwards without pulling it out - but if the engine ran before odds are the pinion's installed correctly, or at the very least correctly for that distributor. Let's move on for now, though - don't mess with that beyond securing the holddown clamp...let's just see if the valves can be adjusted.

When the crank's at TDC you're either on the compression stroke of #1 or of #3. It's easy to tell which, the first three valves from the flywheel end will be shut and the fourth will be open. In other words, when you're at TDC for adjusting the valves on #1, you'll find that all the rockerarms on the RH side are "out" at the top except for #2 exhaust.

If, with the cam and rockerarm in the correct position you still can't achieve any valve lash even with the adjusting screw backed out, there is a serious problem - like a valve seat that's pounded into the head or a valve that's broken. You might be able to tell which by removing the rockers and seeing if the valve stem will move any or not, but either way the head has to come off for autopsy anyway - a loose seat doesn't jeopardize the piston, and it may be feasible to patch the engine by slapping a good head on it.

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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Sat Jan 18, 2014 2:41 pm

Ok. Truth to be told. I sold the prior '77 bus(and kinda regret it). This engine is a '77 picknpull that had been sitting in the garage for 3/4 years. I installed it(with help) without thinking of any checks I should have done first. I adjusted all the valves and they all went easy except for #1 exhaust. I have removed the adjusting screw and still is difficult to slide the feeler gauge through. It will go, just tight.
I pulled the distributor and the slot was lined up just as you described so am hoping all is well there.
Is it possible to pull the 1/2 head with the engine in the bus?
Is it practical?

Thanks

Joseph

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Re: Can't adjust valves, or just how badly did I screw up?

Post by Marc » Sat Jan 18, 2014 10:39 pm

It doesn't sound as though the valve is broken, then - more likely it's stretched (and ready to break) or the seat's recessed...but you haven't 100% ruled out that there may just be a geometry problem (like a too-long pushrod) until you remove the RH rocker assemblies and put a straightedge across the ends of all four valves to see if #1X is protruding more than the others.
It might be worth trying to replace the head without removing the engine if pulling it is a big problem for you. Personally I'd rather work on it on the bench and save the strain of all that hunching over and getting up & down, but it can be done by dropping the rear of the drivetrain enough so the head can some clear of the studs. Don't put too much stress on the front trans mount, and it might be wise to disconnect the shift coupler first so you don't jeopardize the frail linkage bits inside the nosecone.
I'm not especially fond of the Type IV engine (and have successfully avoided working on them for the last twenty years) so you're probably better off getting your advice from someone who is from here on.

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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Sun Jan 19, 2014 8:53 pm

Marc. I tried the straightedge and I need direction in techniqe. I don't SEE much difference when I tried using a flashlight and found it damn awkward to get the light right to see. I tried a feeler gauge and may have noticed a slight protuberence of #1 exhaust. maybe. Should it be obvious? one eighth, quarter, etc?

Thanks

Joseph

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Re: Can't adjust valves, or just how badly did I screw up?

Post by Piledriver » Sun Jan 19, 2014 9:40 pm

One other possibility is that the pushrod isn't quite in the lifter properly, the hydro lifters esp allow that, but many multi-piece lifters allow that to happen these days.

.,..if that is not the case, the seat may be sinking into the head or eroding, or the keepers are eating the grooves they are supposed to stay in.--- for anything but a chewed up valve stem it's going to need replaced, strongly suggest doing both heads.

If you do buy new AMC heads, make sure they have been fully reworked with new seats valves etc as the AMC parts other than the castings are like made from recycled bean cans and unlikely to go 50K miles.

Several places only sell them reworked like this, and for not much more than some other places sell the as-shipped from Spain units.
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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Tue Jan 21, 2014 12:29 am

As far as I can tell all of the valve stems are even or verrry close. Also, the two pushrods I pulled out are heavy and black. I'm guessing that means hydraulic valves? I tried getting the #1 exhaust lifter out and couldn't get it to budge. I was using a wire coat hanger and was worried about scratching the bore. Any suggestions/ideas? All your suggestions are most appreciated.

Thanks

Joseph

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Re: Can't adjust valves, or just how badly did I screw up?

Post by Piledriver » Tue Jan 21, 2014 1:00 am

A really strong magnetic pickup is the usual tool of choice: It is possible the lifter face has ... issues ...and the case would have to be split to safely remove the lifter.

Do not force matters.

It's also possible there are some gummy deposits holding things up (never a good sign) but a shot of Berrymans spray cleaner (or better, a shot of Berrymans B12) will typically dissolve stuff like that in seconds.

If you do have hydros, (and you probably do) adjust them so the screws touch (remove and clean up the screws) plus 1/4-1/2 turn.
Ignore the manual calling for 2 turns of preload, it will just make for lifters that take ages to pump themselves clear of air, the manual was updated many years later. Note that hydraulic lifters do not actually let you not check your valve adjustment regularly... In my experience its the adjustment screws that wear most.

After further consideration...
It would probably be prudent to pull the pushrod tube and make sure the circlip holding that lifters guts in has not gone kaput.
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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Wed Jan 22, 2014 7:57 am

Last night I sprayed Berryman's cleaner into #1 intake and exhaust. I got the lifters to move but only so far and like they hit a ridge. I'm guessing that is the area of wear on both of them. I put it all back together and the feeler gauge is still tight even if I remove the adjusting screw completely. I don't understand what could be causing the drag. I don't think the valve stem could be sticking out that far or it would be more obvious.

Thanks

Joseph

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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Wed Jan 22, 2014 8:53 pm

Ok. Soaked the lifter area with the Barryman's and with a pick finnaly wiggled/pried the lifters on the 1/2 side out. They all look exactly the same. Same size and shape. The #1 intake lifter was a little rough around the came side compared to the others.

I did go back to using a straightedge on the valve stems. This time I was able to measure maybe .012 difference at #1 intake.
I don't know how big a measurement that is. alot? And would that be enough to explain not being able to adjust #1 exhaust?
If so, that means either drop the engine or try to get the head off while still in the bus. Yay, either way.
Thoughts?

Joseph

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Re: Can't adjust valves, or just how badly did I screw up?

Post by Piledriver » Wed Jan 22, 2014 9:00 pm

Do Not Mix Up The Lifters.

If you have a proper place to work, drop the engine by all means, the time it takes to fight with it in place will far exceed the time spent removing and replacing it assuming you have the proper tools etc.

Since it's a pig in a poke, I would pull BOTH heads (have rebuilt) and the jugs and have a look at what you have.
Simply removing the heads destroys any cylinder base seal, so they really have to come off to be resealed anyway.

This also allows getting an eyeball on the cam wear and even the state of the rod bearings, the rods can come out if careful.

Once the engine is out, I strongly suggest visiting a car wash with the engine intact, and take the tin off there and clean the engine properly.

(I realize you may not be in Texas where on average families have at least one pickup truck, but do try... where ARE you?)
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Re: Can't adjust valves, or just how badly did I screw up?

Post by mentalQtip » Wed Jan 22, 2014 9:08 pm

So you're saying that the .012 is clear indication of stretched valve or dropped valve seat?

Joseph

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Re: Can't adjust valves, or just how badly did I screw up?

Post by Piledriver » Wed Jan 22, 2014 9:11 pm

mentalQtip wrote:So you're saying that the .012 is clear indication of stretched valve or dropped valve seat?

Joseph
No decent head guy would let a head out of his shop like that.
(doesn't == never happens)

I bet the seat is getting pounded... or it's a burnt ex have that's going tulip.
If the retainer (only) sticks up higher, the keepers are torturing the valve stem.

Regardless, you need to get an eyeball on it, so it must come apart.

This is a fine example of why you still need to adjust the valves even with hydraulic lifters.
Things are very probably salvageable at this point.

If a valve head or whole valve comes off, the whole engine will look like it took 50 cal hits in seconds.
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