So my repair guy quoted me $800+ bucks to adjust the clearance on one valve. I decide I would save the money and try to do the job myself.

Does anyone know where I can find a DIY, preferably with pictures, showing how to adjust valve clearance on a M103 engine? Been searching and searching but can't seem find someone who has done the job and documented the procedure.

Thanks.

That engine has hydraulic lifters, no adjustment. If there is a noise it indicative of another problem.

__________________

90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff

I wonder what he was gonna do for $800!?

__________________
http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...

Funny thing duxthe1 should mention hydraulic lifters, because that's exactly what the mechanic said he would replace. I think he was going to do them all for $800.

But I know only one of the lifters is making noise. Ignoring my little goof up about valve clearance, the next obvious question is how do I change the lifters? I've tackled several different jobs on this engine but I don't want to get in over my head. Any special tools needed?

Thanks

Anyone?

The lifters have sufficient allowance to compensate for normal valve/valve seat erosion, but if the valves have been ground, sinking the valves without taking a little off the stem tips they could "bottom out". New lifters will not help unless they have more travel, which I doubt. I'm sure there is information in the service manual about this.

So what's the history of the engine? Is the above a possiblity.

It's possible that the lifters are just dirty. Are you using CJ-4 oil???

A high detergent supplement might help clean them out if that is the issue.

There is no sense spending one dime on new lifters unless some good diagnostic work clearly indicates this is necessary, but if they have bottomed out, the head will have to come off and be disassembled so the valve stems can be ground a bit shorter IAW service manual procedures.

Most "mechanics" are too quick to change parts without understanding the real underlying cause of the problem.

Duke

@ Duke2.6 - Thanks for taking the time to post a helpful reply. I've had this car since 07 and have always noticed that one lifter sticks, or whatever it is that it's doing. I don't use C-J4 oil, I have no idea what that is. Perhaps you can tell me? I've been told that most modern oils like are okay to use.

I changed about everything that's fuel and vacuum related on this car since I owned it and still notice hesitation that comes and goes, so I am almost certain it's the lifter.

Now, I've been told that lifter springs can loose compression, and a stuck lifter will retard engine performance due to the fact that it will cause the valves to stay open or shut longer than is needed by the engine. From your experience, is there any truth to this?

Thanks!

CJ-4 is the primary API service category for diesel engines. It has more detergents/anti-wear additive than S-category oils that are designed for MODERN engines that have "roller everything" valvetrains - no sliding surfaces like our vintage Merc engines.

You can buy it anywhere oil is sold, but it may be in a different section than the S-category oil.

Download the following link and read the oil article beginning on page 3. I originally wrote it for "The Corvette Restorer" magazine, but it's equally applicable to any vintage engines with sliding surface valvetrains.

http://www.westcoastwillys.com/WCW_Sept08_small.pdf

The valve springs in these engines are not highly stressed and should last several hundred thousand miles.

It's possible that you have a collapsed lifter - i. e. it's experienced a mechanical failure and has collapsed in which case the engine will make a loud ticking sound that you can tell is in the valve train, and since the valve only opens partially, it will feel uneven or like it's missing. This happened to my 1984 190E 2.3 while it was under warranty, but I knew exactly what happened.

If you don't feel competent to evaluate a collapsed lifer, take it to another mechanic for diagnosis. I don't think the one you have now knows what he's doing. Most shops that specialize in Mercs should be easily able to determine if the lifter is collapsed or just sticky.

If it is just a sticky lifter, use some "sticky lifter" additive along with CJ-4 oil on your next change. There are several brands of these additives that have a very high dose of detergent and they can be effective in cleaning out the lifter so it works properly again. Check local parts stores, and once clean, continuing to use CJ-4 oil and the OE change interval will keep them clean.

Duke

@Duke2.6 Thanks for the info on CJ-4. I noticed that you mentioned CJ-4 being the primary service category for diesel engines. But just to be clear, my vehicle has a gas engine (M103). I'm sure you know that and you recommend CJ-4 for gas engines as well. Just trying to remove all doubt to avoid pouring something in my engine that's going to complicate things.

I guess next on my agenda is to have the car diagnosed.... maybe...I don' think I've mentioned this but the lifter ticking goes away when the engine reaches OT. So that leads me to believe it's just getting stuck. Later tonight I'll do a cold start to see if I can get the ticking on video.

I gather you did not read the article that I linked to, or if you did, you need to read it several more times to absorb all the information. Everyone on this forum should read it - actually print it out and put it in your car files and reread it whenever an "oil question" comes up.

It will answer all your oil questions including the couple of dozen you forgot to ask.

You most likely have a sticky lifter.

Duke

Duke, great information, interesting reading. As suggested, owners of older engines (early M103 in my case) can go to school on your write-up. Thanks.

__________________
1988 California version 260E (W124)
Anthracite Grey/Palomino
Owned since new and still going strong and smooth
MBCA member

Past Mercedes-Benz:
1986 190E Baby Benz
1967 230 Inherited from mom when she downsized
1959 220S Introduced me to the joys of keepin' 'em goin'

There are only 10 kinds of people in the world--those who understand binary and those who don't

@ Duke2.6 I glanced over it. I'll do another read-through. It's good material but, but I'm just wondering why I've never heard anyone talk about CJ-4 before. God only knows the number of times I've asked oil related questions.

In the article I describe the American Petroleum Institute and how they have been setting engine oil standards since at least the 1950s. And those API service categories have been on every jug of oil you bought for at least the last 60 years!

I go on to add that few people even including "car guys" know about the API or have any knowledge of the service category system, but it's all in the API 1509 document that you can pull right off the Web.

Why is this so? You tell me. Most guys listen to marketing/advertising hype and read Web sites full of backyard mechanics who run around like a bunch of chicken littles screaming that the sky is falling rather than seek out authoritative information on the subject even though it's only a few keystrokes away.

If you want to understand engine oil and how to select it for any car you own, you need to do more than "glance over" the article. You need to read it thoroughly (and look at the Web links) and absorb the material. Then you will never need to ask another engine oil question again because you will know more about engine oil than 99.999 percent of everyone you ever talk to about the subject.

In the process of achieving permission from the API to use their symbols, their techincal people reviewed the article and did not recommend changes of any kind.

Duke