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post #21 of 99 (permalink) Old 06-11-2019, 01:59 PM
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Do you have an idea as to what changed in the engine to make the noise come back so noticeably? I apologize if I have missed something. I have a tic too and bought the go-no-go but now, based on your experience, I'm thinking I'll live with the noise:ee
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post #22 of 99 (permalink) Old 06-11-2019, 02:03 PM
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Sorry, just reread your comments: some junk broke loose and clogged oil hole. Okay got it. Thanks for sharing all your trials. Hopefully you can get it sorted!
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post #23 of 99 (permalink) Old 06-11-2019, 03:13 PM Thread Starter
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The more I look into this problem the more convinced I become that loud rockers are not going to be quieted by substituting thrust washers that are fractions of a mm thicker.

I can't shake the notion that my problems with nasty rocker tics are 100% the result of oil flow restrictions either to or within the hydraulic compensators.

This last event... where the compensator was obviously compressed and did not return to full height after I removed the rocker but did return to full height when I removed the compensator from the head shows at the very least that the compensator was stuck in a compressed state.

Remembering that one of the tests to determine if a compensator is good, is to remove the rocker and using the wooden end of a hammer handle, push down on the compensator. It should offer resistance but it should compress. The strange thing is that after I removed the compensator that was so obviously compressed, I could not get it to compress again no matter how hard I pushed on it. This compensator went from a significant compressed state to as hard as a rock fully uncompressed state as if by magic.

I've never taken one of these compensators apart but I would assume that the ball should move in and out (perhaps only slightly) as its primary function is to "compensate" for variations in dimension via hydraulic action. So when I couldn't get this compensator to give even a fraction of a mm... even using a large channel lock pliers... I assumed something was wrong. I sprayed brake cleaner into the little hole but still the compensator wouldn't budge... so I did what any red blooded male would do... I put it in a vice. Now that got it to compress, and it also ejected several drops of oil from the little hole.

So now the compensator compresses with only moderate pressure and the ball moves in and out freely. I'm guessing there must be a spring inside that is supposed to return the ball to full up position when there is no pre-load present (i.e. rocker arm removed).

So why then was this very same compensator stuck in a compressed state when it was sitting in the head with the rocker arm removed? Shouldn't the spring inside the compensator have returned the ball to full height? It would appear that something inside the compensator was stopping the spring from returniong the ball to full height and I'm guessing that something was either dirt or the oil itself that was trapped inside the compensator and the spring didn't have enough strength to overcome whatever was restricting the ball from moving up (but when I squeezed the bejesus out of it in a vice, whatever was stopping it from returning was overcome and now the ball moves freely in and out).

Of course this is all just guesswork on my part but it does begin to ring true when you consider that one of the functions of the thrust washer is to set the proper pre-load. I'm now assuming that the pre-load is used to overcome the spring tension inside the compensator.

I poured one quart of Marvel Mystery Oil and an entire can of Sea Foam into the crankcase. I think I'm done jerking around with this thing for at least the next few hundred miles at which time I'll drain the oil, remove all the compensators, soak them in some kind of solvent and then reset all the thrust washers to nominal. Then we'll see what happens.

p.s. Throughout this post I've referred to the top of the compensator as a ball. While the top is indeed ball shaped it is not itself a ball but rather a shaft with a rounded top whose diameter is greater than the shaft diameter.

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post #24 of 99 (permalink) Old 06-11-2019, 03:52 PM
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Jyuma, I agree with your approach. Hopefully the crud dissolving mix will clean things out. You have worked long and hard on this baby. Time for a break to get some top down cruising done. You deserve a break. The rocker that was worn on my car, was visibly dished, I did not measure it, but it was noticeable. Plus the camlobe was kinda scored. But, just a new rocker quieted it down.I know I'm living on borrowed time. But, hoping will make it till falll and then I can deal with cam..Keep us informed....
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post #25 of 99 (permalink) Old 06-11-2019, 06:27 PM
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Kudos to you for your determination to find the ticking culprit. Finding the stuck compensator is interesting. If I'm understanding this right, the compensator originally being stuck in it's compressed position could have been responsible for the tick? I'm guessing, but I imagine that oil pressure may also be partially involved in achieving it's extended position, so if oil can't make it's way up into the compensator due to an obstruction..? Strictly conjecture on my part, and I may very well completely out of bounds.
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post #26 of 99 (permalink) Old 06-12-2019, 04:31 AM Thread Starter
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Kudos to you for your determination to find the ticking culprit. Finding the stuck compensator is interesting. If I'm understanding this right, the compensator originally being stuck in it's compressed position could have been responsible for the tick? I'm guessing, but I imagine that oil pressure may also be partially involved in achieving it's extended position, so if oil can't make it's way up into the compensator due to an obstruction..? Strictly conjecture on my part, and I may very well completely out of bounds.
I have had all the compensators out, cleaned, measured and returned to their respective positions in the head many times over the past several weeks... how is it that I never noticed one of them being "stuck" in a compressed state? The obvious answer is that it wasn't stuck before and something caused it to "appear" to be stuck yesterday, but then why did it become "unstuck" as soon as I removed it from the head? The obvious answer is that it wasn't stuck due to something internal to the compensator but rather something external to the compensator, which is why removing it from the head allowed it to return to it's unloaded position.

One somewhat curious observation is that the compensator is a bit like the "roach motel"... there is only one path for the oil to flow either in or out... that little hole in the base. I'm surmising in my case the oil gets in but it can't get out (check valve?).
Thrust washer deviation-merccompensatoroilhole-copy.jpg



It would appear that something upwind of the oil hole in the compensator may have been clogged... something that was removed when I removed the compensator from the head.

There is a somewhat larger hole in the head that feeds oil to the base of the compensator (arrow on the right in the picture below) but that hole is too large to be blocked by small amounts of floating crud in the oil, so the oil feed hole can be ruled out as the culprit. That leaves the ring (culvert?) that is cut around the top inside of the threaded hole where the compensator screws in (see picture below).

The arrow on the left points to what I am calling the "culvert" which is wider than the threaded portion and distributes oil around the entire inside top circumference of the compensator mounting hole. Ideally, when the compensator is installed in the head, the hole in the base of the compensator should line up with the oil feed hole in the head, but I'm assuming that even if the two holes don't align perfectly, the culvert will distribute the oil in either direction around the compensator and find it's way to the oil feed hole in the compensator base. I suspect there is where I will find my problem.

Thrust washer deviation-mercheadcompensatormountinghole-copy.jpg

I know I said I was done jerking around with this problem for now, but you will forgive me if I perform on final test... I'm going to clean the culvert.

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post #27 of 99 (permalink) Old 06-12-2019, 06:09 AM
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Your theory makes good sense. I hope it proves to be true, and you can finally say "problem solved". Having to listen to a tick would be annoying. Having it return after doing the amount of work you've already done would be VERY annoying. Good luck!
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post #28 of 99 (permalink) Old 06-13-2019, 05:25 AM Thread Starter
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And the saga continues...

Yesterday I removed all the rockers, thrust washers and hydraulic compensators on the drivers side. I chose the drivers side because I was convinced that the tic was coming from that side.

I cleaned everything on that side... I even sprayed brake cleaner into the oil supply holes in the head for the compensators and then blew it out with compressed air. Thousands of tiny black particles smaller than a grain of sand came gushing out of the other oil supply holes. When I wiped the little black specs with a paper towel they appear to simply dissolve into black smears on the paper towel.

Then I used a football (or basketball, whichever you prefer) inflation needle pressed against the tiny oil hole in the compensators and blew compressed air into the compensators. I could feel the compensator ball expand out (couldn't detect the motion by eye but I could feel it) and oil leaked out of the place in the top of the compensator where the shaft with the balled (round top) leaves the compensator body.

I cleaned the inside and all around the holes in the heads where the compensators get screwed in and then I reinstalled all the compensators... at the same time I verified that the little hole in the compensator base and the oil supply hole in the head indeed do not line up. The compensators tighten down with the oil hole at random locations so it is important that what I called the "culvert" (the beveled edge around the top of the compensator mounting hole in the head) is clear of any obstructions.

One by one I reinstalled the thrust washers and rockers in the same positions that came from... stopping to use the go no-go gauge on each compensator. As would be expected, the go no-go gauge indicated on every compensator that a thicker thrust washer was needed. I assumed this was due to the fact that the compensators had not yet been cycled through by rotating the engine for the recommended 30 seconds.

When I finished reinstalling all the thrust washers and rockers, I used the remote start (with power disconnected from ignition and fuel pump) to engage the starter and crank the engine for 30 seconds. I then rechecked every valve using the go no-go gauge and every valve checked nominal. That's when I realized what the go no-go gauge is actually designed to check... pre-load and only pre-load.

So what is pre-load? Pre-load is a measurement of the distance from the top of the ball of the compensator to the top of the surface that the compensator screws into, but only after the pressure from the valve spring is applied. This is a known (nominal) distance and the length of the indicator on the go no-go gauge is set to visually show that distance falls within the 1.5mm range of the measuring slot on the go no-go gauge. Given sleight variations in the internals of the lifter, that distance (under the load of the valve springs) may deviate by some amount positive or negative. That's what the thrust washers are intended to compensate for... sleight variations in the loaded distance between the top of the compensator ball and the surface the compensator screws into. That's it! The go no-go gauge tells you nothing about anything else in the valve train other than the distance from the top of the ball to the surface of the head.

So sleight is the difference between the totality of the length of the valve stem above the seat of the valve, plus the thickness of the thrust washer, plus the dimensions of the rocker, that plus or minus deviations are accommodated by varying the thickness of the thrust washers in increments of .35mm... that's about .013" (13 thousandths of an inch). So much for eliminating annoying rocker tics by changing thrust washers... not gunna happen.

So what can cause an annoying rocker tic? The short answer is "any of the components in the valve train", but the more useful answer is a worn rocker or a collapsed hydraulic compensator. Of course a bent valve could do it or broken valve spring but we're looking for the more common cause, and that would be a worn rocker or collapsed (or partially collapsed) compensator. Setting the precise pre-load via the use of the go no-go gauge may make the anal-retentive among us feel better, but it is not likely to quiet down a noisy rocker.

bTw... Upon restart, the tic was still there, even though I had set the pre-load to nominal via the go no-go gauge on every valve on the drivers side. Today I'll do the same extensive cleaning and pre-load adjustment to the passenger side... just in case.
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post #29 of 99 (permalink) Old 06-13-2019, 07:16 AM
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Good luck with the right side. At this point, I think the Benz gods owe you one...
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post #30 of 99 (permalink) Old 06-13-2019, 08:52 AM Thread Starter
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Good luck with the right side. At this point, I think the Benz gods owe you one...
Do the Benz gods pay in bitcoin or PayPal?

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