You got me on that one so go look at hydralic valve lifters on google. I just did. Good pictorials.The newer ones designs seem different than the older larger buick ones that I dealt with their internals long ago. Same basic principals though apply.

I have had no reason to take a newer designed one apart. If nothing else it shows that varnishing inside an engine is counter productive to a lifter functioning well. If one has suspect problamatic bad lifters it may be pruident to devarnish them before calling them shot. Soaking in a good solvent and working them may clean them up internally. Most testing and cleaning should be enabled by using the drill press as a vertical force device..

Here's the factory procedure on testing OM60x hydraulic lifters, complete with nifty cross-section cutaway drawings... see attached PDF file.

:stuart:

Hey, that pdf says to use a magnet!

Sixto
87 300D

They quote no lifter leakage all. In the real world I do not know if that is factual. If so pumping them up before installation might give valve/piston interference. Although this seems to be eliminated by the short range of automatic adjustment action of that particular design of lifter. This was intentional to make them quieter on start up I suspect.

On a valve job for those engines there must be either various custom height lifters available as the valve on seat stem protusion measurement result may be critical. I suspect some lifters may have had their skirts ground down or the valve stems over the years as it is reported the last cylinder on some of these particular engines (606) have been reported with deep valve recesses on the last cylinders seat insert.. Changing out to a new seat would be the proper and really required repair. Also when the edge of a valve is reground it extends the stem a little higher as well. Seems to me that to do a decent valve job on that type of head you have really to pay attention.

It's physically not possible for a fully-pumped lifter to press the valve far enough to contact the pistons. It's simply not designed that way.

:nuke:

I know that this is an old thread, but I thought I'd share something I learned the hard way.

When using a drill press or clamp to squeeze the piston, ensure that the piston is pushed straight down. In other words put no side load on the piston or you will destroy the lifter. You know that you killed it when the piston becomes easy to depress. If you can easily do it with your thumb, your lifter is ruined.

I just replaced all my lifters with new in the box ones. I just put them in not doing anything special. I still got a tick/clack, how does that preset procedure go?

I though that pumping up and testing for fluid hold in comparison to similar ones would only be practical using a drill press. There has to be some internal allowance for bleed down. You just do not want rapid bleed down in comparison to other lifters in the batch you are testing.

The internal spring alone perhaps allows this to slowly take place. I guess what I am really thinking is some modern lifters look somewhat more complex in illustrations than the simple ones I took apart so many years ago. My guess is that if there is no oil already in a given lifter all you have to overcome is an internal spring that may not be very strong.

So if you where to finger push an empty lifter in a bath of oil. On the pistons upstoke it will intake oil when you remove the finger pressure. You will then only be able to finger push the lifter piston down the second time as far as the accumulated internal oil inside allows. Constant finger pressure continued the oil may very slowly bleed back out perhaps. The bleed down may be quite slow though with only finger pressure. Finger test is not adequate as it does not compare with lifter in service pressures.

The lifters are designed to constantly adjust to provide near to zero valve lash. My guess is say you mark and extract a set of lifters. Take some transmission fluid and pump them up and let them sit a day. This may get rid of any varnish internally. Then test them in motor oil. You hold pressure till they drain down. Then pump them up and check their ability to stay up time wise in comparison to the others. At onetime lifters where so cheap you just grabbed a complete set if you had one or two in the engine that would not hold.

Now if the oil feed passages are badly sludged up there may be inadaqate oil reaching the lifters for them to function well should always remain a consideration if all the lifters you remove test well. I guess you could even just have one or two feed passage sludge problems as well.

So perhaps the first step in dealing with noisy lifters may be to put a synthetic oil change in place or a real cleaning additive in the oil supply. In the old days it was adding a quart of automatic transmission fluid to the oil and running the car in service for awhile. This seemed to loosen up crud and varnish in the lifters and oil feed passages many times.

I know a lot of members know this type of issue. I just posted it if perhaps a few did not.

A list of common problems experienced with lifters in my opinion.

The cylinder and piston varnish up to the point the internal spring is unable to push the piston in the lifter upward.

The arrangement for the check valve to enable the ability of the lifter to hold oil well enough is shot. Broken spring internally or whatever arrangement is used to enable the piston internally always to have upward internal movement available even with no oil present. Very low force levels required for this.

Most common perhaps is the piston and cylinder have just worn so much the required time to retain the oil internally in service just does no longer exist. These are the ones you typically manage to pump up in a drill press and they compress down again much faster than average as the oil is leaving far faster than the design paremeters allowed. Or at worse they will not pump up. you cannot totally duplicate test conditions as a lifter experiences in actual service. Still in general the slow hand testing will reveal most the common issues. One last thing that crossed my mind. As the engine oil heats it thins. So it may be better to use a thinner oil for testing at times. A cheap quart of say 0-20W oil cold may be hopefully about the equivalent of normal hot engine oil. If they pass in that viscosity oil they are probably just fine. This testing is not rocket science remember. Anyone can really do it that has access to a drill press.

I had the same issue on my 1993 300D. All new lifters, still a loud ticking.

Turned out to be the head gasket had started to fail at the front oil galley, and debris from the gasket was blocking the oil passages to the lifters. Lack of oil at the lifters caused ticking even with brand new lifters installed. The fix was to remove the head, carefully clean all the oil passages, and replace the head gasket. It was silent afterwards. While I was in there I also replaced the crank seal and converted to a pressure-operated wastegate. Photos are here:

http://www.w124performance.com/images/OM602_head/


:zorro:

Too funny, Winmutt was quoting me!

For the record, Yes I did simply use my fingers/thumbs, and very gradually I was able to get the oil out of that lifter. Once I was able to get a little action in the piston, and some air entered, it became much easier to get the oil out.

I find myself now replacing the head AGAIN, this time installing a used #17 head.

It turns out that #20 head was internally cracked. Machine shop that did the work did not catch this, I ended up building my own hot-tank and pressurized the head via the exhaust manifold. Crack was confirmed by air bubbles escaping from the coolant passage at the front of the head.

I recently completed bleeding down all the lifters for this head installation, this time I used a small vice. One lifter bled down with far less pressure than the rest of the lifters, so that one will be replaced with a different used lifter.

Another reason lifters should be checked first before replacement. If the oil feed is problematic they cannot work properly. I do not know the cost of a set of ifters for this engine but may be a little painful if not needed. I also suspect lifters are not solvent cleaned often if they seem bad. The clearances are so tight that any varnish internally is signifigant.

Do not be surprised to have an oil feed problem to the lifters. We had one at one time we could not solve. There had to be a crack into the oil passage somewhere was our final unfound conclusion. This was a german engine but not Mercedes.

It was quite obvious, looking through the intake manifold, the "before" and "after" position of that valve. Before I bled out that lifter, it would not fully close. After, it closed right up. While I had the camshaft off and the lifter out, I removed the keeper and valve spring, and made sure the valve was not sticking in the new guide. There are only a few parts involved here: valve, valve seat, valve guide, spring, keeper, hydraulic lifter, camshaft. Spring and keeper are working to close the valve, not open it, and given that the valve closed up as soon as the camshaft was removed, the spring was strong enough to do the job.

I measured the height of each lifter (with camshaft removed) and compared them, found a one or two more that were also high (exhaust side I think) and bled those down.

Once everything was put back together, the engine was smooth as silk. I can think of no other explanation for a valve not closing. Pulling the camshaft and the intake manifold, messing with all that I did, and putting it back together, that took me a fair number of hours. If I could have done something differently to achieve the same result, I'd love to know what that is.

I don't think you have the same problem I did (lifter too full of oil). New lifters should be empty, and with engine operation the oil pressure should "inflate" them to take up the gap between the top of the valve stem and the camshaft.

Either one (or more) of your lifters are bad, or one (or more) are not getting sufficient oil pressure, or something else is making your noise. Ticking lifters are a classic sign of failure of the head gasket at the front oil passage for OM601/2/3 engines.

Well, I may have just destroyed twelve lifters, but I don't think so. I used a vice and a block of wood to squeeze all the oil out of the lifters. Some lifters required about 20 or more cycles of pressure/release, some only a few, but all were bled down until the piston moved easily by thumb. My goal was to get them completely bled so they did move easily by finger pressure alone.

Reading the procedure that Dave posted, it looks like the piston can be removed and the valving mechanism inside cleaned/inspected.