Anything to silence the ticking 420sel - PeachParts Mercedes-Benz Forum

SCOTTFISH · #1 05-04-2004, 09:02 AM

I have had my 90 420sel reworked with a timing chain job about 6-8 months ago. Everything has been fine. All of a sudden, my car started running extremely rough. When checked by a German Motors shop with and found plugs and wires were bad. That has been replaced and now I have noticed a tapping noise. They checked the timing chain and the cams. He stated there was a very, very minimal space more than should be with the cam. (I don't understand fully) He did say that with the minimal space there was nothing that could be done to reduce it. I didn't think anymore about it and of course, didn't ask if there was anything to minimize the noise. But I thought I would ask here before calling back and asking. From all indications, he did not feel it was hurting anything and didn't feel there was anything mechanically that could be done to stop the noise. It is not loud, but it sounds enough that it bugs me. I may have to just live with it. Thanks for any and all help here.

afmcorp · #2 05-04-2004, 03:03 PM

hello scottfish

well you need to consider a valve compensating element [lifter] is the culprit. i'm not saying it is i'm merely suggesting that this should be looked at.

if it is the element then leaving it alone will lead to additional failures. such as rocker failure and even possible cam damage. if this is it it'll cost about 20$ for the part [assuming no other damage] 5$ for the valve cover gasket and maybe about 1 hours work.

this very thing happened to my 420 and it cost me a cam, rockers and lifters.

now it might only be an exhaust leak ticking away. but the minimal space the guy was talking about makes me think of element height being off. and perhaps ready to add shims to make up for it. but if it's ticking i would just replace the thing.

let us know what was the problem. if it's the element let me know which one. i'm working on a theory that the back two cylinders are the ones to go first.

good luck

SCOTTFISH · #3 05-04-2004, 03:36 PM

Hey, Craig. It's good to talk to you again. He did not seem too concerned with replacing anything. He mentioned the shims but he said that with the minimal slack present, it would be hard to get perfect and would not be cost effective. I am kind of at a loss. It did not do that much at all before I ran into problems with the plugs/wires. Any further suggestions? I appreciate your help.

afmcorp · #4 05-04-2004, 05:03 PM

well now...

if it is ticking and it is the lifter/rocker assembly that means there is some kind of gap. weither it be from the hydraulic unit collasping or the rocker gettin a bit of a divet on the cam lobe area it's a real issue that should be addressed. it won't heal itself so the only place to go is downhill.

now i'm not kidding about the cost. the element is only about 20 or 22 bucks and the valve cover gasket is less than 10 bucks. if i remember right you only need 2 sockets to do the job. one for the valve cover and 1 for the comp element. now i'm such a tool nut that when ever i do this kind of work i either buy the special tools or make them myself. now i wouldn't bet my life but when i replaced the old elements with new every one of them came out as on spec as the manuals calls out. so the only tool you might have to get is the valve spring compressor which you probably can get loaned free from say autozone or rent one from perf products.

so IMHO if its broke which it sounds very likely it needs to be fixed. if for no other reason than to keep your sanity and to keep you from putting your fist into the dash.

well i just looked at your post again and "he wasn't too concerned about replacing..." made me think of "you can pay me now or pay me EVEN MORE later."

good luck!!! let me know how this puppy comes out!

SCOTTFISH · #5 05-05-2004, 09:00 AM

Craig, thanks for the info. I am pretty mechanical in ability, but don't have a lot of experience in the tougher jobs. Is this a hard job to do and what sort of time do you think it would take to do the job? When you talk about the element, is that what I would ask for in buying the part or is there another name for it? On another note, I drove the car to work today as I usually do and I did not notice the sound too much as all, but I verified it was still there when I parked and listened with the door open. It is possible that the sound was there all along, but I just didn't notice it or it was not as loud. Thanks for the help.

MrCjames · #6 05-05-2004, 09:25 AM

How prevelant or loud is the tapping sound? Is it consistent? Is it more of a tick noise that comes and goes in brief cycles?

autozen · #7 05-05-2004, 11:26 AM

You said you had the car reworked with a timing chain job. I'm not really clear as to what that means. If you had the heads off, they were probably machined which means ypur mechanic needs to check the clearance of each lifter with a special MB adjustment gauge and install the appropriate shim. Ask your mechanic if he has the tool. Yes you should replace a failed lifter.

Peter

SCOTTFISH · #8 05-05-2004, 12:18 PM

I had a timing chain, guides, etc. done about 6-8 months ago and didn't have any ticking noise that I can remember, at least it was not as noticable as it is now. I never noticed the ticking noise until I had problems with the plugs and wires causing a really bad idle. It ended up being that 1 or 2 of the plugs were not even firing. I asked the German mechanic what I could do to quieten it down some and he said get rid of the synthetic oil and use 20w50. In my area, 20w50 is not a good weight to use and I thought that was sort of a cop-out answer. He said that mercedes has said not to use synthetics. I find it funny that Mobil 1 states right on the bottle that it meets all guidelines for MB, Porsche, and other European sedans. Not getting into the synthetic-or-not discussion that I have seen on these boards in the past, I personally feel the syns are slicker and reduce the wear on the engine over time. I have had nothing but good luck with syns. But, back to the noise, it is not real loud and today it must have been there, but I didn't notice it like I did in the past few days. I know the noise comes from the passenger side valve cover. The driver's side is completely quiet. Thanks for all responses.

afmcorp · #9 05-05-2004, 01:44 PM

scottfish

what you need to do this job is a socket and rachet for the valve cover, a 24mm [i think] socket for the "valve compensating element" [equal to our lifter in us cars], you'll need a torque wrench for the element and valve cover bolts. the final is the valve spring compressor. look at the manual to see the type needed. perf prod probably has them to rent and maybe autozone or advance auto.

this is an easy job. probably taking the misc stuff over the valve cover will be the hardest or time consuming.

i'm thinking for this job maybe 1 hr to 2hr if you relax. you may want to consider the oil tube plastic while there if your mechanic didn't replace it when the chain was done.

as far as the height of the comp element my guess is that it will be fine. as for machining of the head issues. even if they faced the head that shouldn't have anything to do with the element. because the areas that we are discussing are not machined. the only time you should consider it an issue is if a valve job was done. then the seat in the head and the valve will be machined which will likely change the height issue.

look in the fast lane parts and look for valve compensating element. they show a picture of the part.

i'm confident that you can do this. if you run into a problem get back to the forum. if you're in doubt about the element height then rent that from perf. products and the compressor.

you've got my email add give me a yell if you run into a problem.

i would also think some of the other members can also lend some advice here.

good luck!!

Theurig · #10 05-05-2004, 03:22 PM

This has probarbly never happened to anyone else. But I had a tapping noise on my car coming from the passenger side area. My tech said it was lifter tap. One evening I opened the hood and noticed the #1 spark plug wire shaking, the noise was coming from there. Yup the spark plug was loose. I tightened the spark plug and the tapping/ticking is gone for good!!! Probarbly not your case but it might be worth checking considering that your plugs and wires were recently changed.