Valve issue, 1600SP type 1

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Stray Catalyst
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Valve issue, 1600SP type 1

Post by Stray Catalyst » Fri Jun 20, 2014 11:04 am

In January I broke the helicoil for the spark plug on one of the heads on my car. When I took the engine apart, I broke studs off the other head, so I replaced both heads with 1500SP heads I had on the shelf, used but in visually good condition.

Now I've got the engine back in the bug and am trying to adjust valves, but when I back the #2 exhaust out to try to get the .006 - I can take that right out, and still have no clearance at all. The rocker presses against the valve directly. I loosened the two 13mm nuts that hold the rocker arms against the head, and there's clearance then - the valve does not appear to have broken free or slipped its retainers.

How do I fix this? Shorten the push rod, or shims under the rocker arm assembly, or something else?

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Marc
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Re: Valve issue, 1600SP type 1

Post by Marc » Fri Jun 20, 2014 11:31 am

You replaced the heads, but did not attempt adjusting the valves until after the engine was installed? Image

Since you didn't crack open the bottom end there's no concern that the cam is misindexed, but are you positive that the engine's at #2 TDC when you see this?

Occasionally a pushrod will hang on an internal edge of the lifter rather than seat properly, making it protrude further. Usually it'll pop down into place by itself when the engine's turned over but not always - remove the rockeram assembly, check that the ends of the pushrod aren't damaged, and as you put it back in make an effort to have it hit the center of the lifter...odds are the problem will be gone when you put the rockers on this time.

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Re: Valve issue, 1600SP type 1

Post by Stray Catalyst » Fri Jun 20, 2014 11:51 am

I didn't adjust it while it was out of the car - I borrowed an engine stand that wasn't made for VW engines and had to do some fairly dodgy jury-rigs to get it to hold the engine at all.

I *think* it's at #2 TDC, but I'll go through the procedure again and ensure that I'm starting with #1 at TDC before I rotate the engine CCW. If that doesn't change things (and I'm pretty sure it won't - but if I knew for sure, I'd not be asking questions) I'll remove the rocker arm assembly and see if that push rod is protruding. I've turned the engine over without changing the effect on that valve, but it did sit for the winter with that valve open, I think. The valve itself moves (turn down the adjuster and it moves) but that doesn't tell me if the cam follower has managed to get stuck in the open position, or if the pushrod is on that ridge.

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Re: Valve issue, 1600SP type 1

Post by Stray Catalyst » Mon Jun 23, 2014 5:07 pm

Ok, I've confirmed TDC with a pencil through the #1 spark plug hole. The mark on the distributor is in line with the line on the rotor, as expected. Adjusted valves for #1, rotated the engine counterclockwise 180 to work on #2. Intake vale, no problem. Exhaust - still no clearance at all.

Removed the rocker arms, swapped pushrods from intake and exhaust, tapped the exhaust one several times with a hammer, reinstalled pushrods... intake was still the same clearance, so I'm guess I didn't just have one long pushrods mixed in with the rest, as the exhaust valve is still in contact with the rocker, even when I've spun the adjuster back until it unscrews from the back of the rocker.

When I replaced the heads, that was as deep into the engine as I got - pistons and cylinders stayed installed, as it was the easiest way to keep gunk from wandering into my engine. The car was my daily driver before this, and ran reliably. The heads I bought used, and didn't rebuild them - they were clean (not cleaned) 1500SP heads. I installed them as drop-in replacements - could the problem be I forgot the copper washers (that I've read in many places, I should not use at all)?

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Re: Valve issue, 1600SP type 1

Post by Marc » Mon Jun 23, 2014 8:28 pm

Based upon what you have reported so far, it would seem that the #2 exhaust valve stem is protruding further than the other three on that head. With the rockerarm assembly removed, place a straightedge across the ends of the valve stems. If #2 Exh is higher than the others, there are a couple of ways to compensate without removing the head. BUT if the cause is a loose valve seat that's pounding its way through the head, you still won't be out of the woods.
Since swapping the pushrods made no difference, if the problem's not with the valve installed height the only thing left is a problem with #2 Exh lifter that's making it "too long"...and if there was no such issue with the former heads, that would mean something weird like a piece of hardware that fell into it while the work was in progress.

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Re: Valve issue, 1600SP type 1

Post by Stray Catalyst » Mon Jun 23, 2014 8:38 pm

I'll check that tomorrow when I get home from work. If a piece of hardware were stuck in it, wouldn't the valve be permanently depressed? I had that happen to a previous engine, which ingested a 10mm bolt.

If the valve is bashing itself through the head, then the "replace both heads" job I just did is going to have to get repeated, I fear. I'll be seeing my mechanic (and his junkyard, and his part warehouse) later this week, I'll add heads to the shopping list if that's the case.

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Re: Valve issue, 1600SP type 1

Post by Marc » Mon Jun 23, 2014 11:22 pm

Stray Catalyst wrote:...If a piece of hardware were stuck in it, wouldn't the valve be permanently depressed?...
Not necessarily, it's conceivable that something like a wavy washer fell into the lifter, which'd be enough to keep the pushrod from seating fully without jamming anything up.
If #2 Exh was just sunk deeper at the last valve job without having the stem trimmed shorter to compensate the engine can still be run, it just won't be easy to get the rockerarm geometry right on that side. You could add lash caps to the other three valvestems, or switch to swivelfoot adjusters on them, and then shim the rockerarm assembly out enough that adjustment's possible on all four. Not optimum, but it'll run. If this is the case, odds are that they didn't shim that valvespring either so it may be a little light in the tension department, but probably not enough to be a problem on a stocker.

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Re: Valve issue, 1600SP type 1

Post by Stray Catalyst » Sun Jun 29, 2014 10:17 am

Straight edge showed a few thousandths of an inch difference between the ends of the valve stems. Less than .006 difference, so this isn't the reason for that valve to be in contact, as far as I can tell.

I don't have another set of rockers (unless I feel like using ratio rockers on an otherwise stock engine) so I think shims are my next option. The Bentley manual doesn't have anything that I've found that seems to describe this symptom, but their description of a valve adjustment assumes that nothing goes wrong, and that the valves you're adjusting are known to have been working before the adjustment started.

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Re: Valve issue, 1600SP type 1

Post by Phil69 » Thu Jul 03, 2014 3:46 am

Could it possibly be that the engine timing is 180 degrees out and on or approaching the exhaust cycle for number two piston?

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Re: Valve issue, 1600SP type 1

Post by Marc » Thu Jul 03, 2014 4:03 am

Stray Catalyst wrote:Ok, I've confirmed TDC with a pencil through the #1 spark plug hole. The mark on the distributor is in line with the line on the rotor, as expected. Adjusted valves for #1, rotated the engine counterclockwise 180 to work on #2. Intake vale, no problem. Exhaust - still no clearance at all.

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Re: Valve issue, 1600SP type 1

Post by Tony Z » Mon Jul 07, 2014 3:09 am

Stray Catalyst wrote:Ok, I've confirmed TDC with a pencil through the #1 spark plug hole. The mark on the distributor is in line with the line on the rotor, as expected. Adjusted valves for #1, rotated the engine counterclockwise 180 to work on #2. Intake vale, no problem. Exhaust - still no clearance at all.
Just wondering.... when you confirmed TDC for #1 could you adjust the valves on #1? Or did you just see the piston as being up at TDC and said, yip, thats TDC?
Reason I ask is that it sounds like you are trying to adjust your valves with the engine on the wrong cycle. Remember, the 4 stroke cycle is 720deg (2 revolutions). In the correct TDC cycle both valves should be closed. In the other cycle, the exh valve will still be open. (I cannot remember the cam specs for a stock engine, but I think it has a negative overlap, so the inlet valve will be closed).

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Re: Valve issue, 1600SP type 1

Post by Marc » Mon Jul 07, 2014 9:57 am

Tony Z wrote:Just wondering.... when you confirmed TDC for #1 could you adjust the valves on #1?...
Stray Catalyst wrote:Ok, I've confirmed TDC with a pencil through the #1 spark plug hole...Adjusted valves for #1, rotated the engine counterclockwise 180 to work on #2...

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Re: Valve issue, 1600SP type 1

Post by Stray Catalyst » Thu Jul 24, 2014 11:27 am

Shims made the difference - .050" and suddenly the valves could be adjusted. Now the motor runs, idles as it should. Thank you for the advice.

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