What did the mechanic do?!?! - Page 2 - PeachParts Mercedes-Benz Forum

Johnhef · #1 10-20-2008, 09:54 PM

Quote:

Originally Posted by david s poole

based on your info,i would think that your problem lies with the bolts that hold down the rocker assemblies.the head is aluminum and the bolts are steel and one or more of the bolts [probably on one assembly] have pulled loose.there are two choices.find the bolt[s] with the pulled threads and buy some bolts that are 10mm longer [at the threads]and you can take advantage of the extra unused threads at the bottom of the hole.tighten to about 15ft/lbs.or to do the job correctly,buy a helicoil kit and redo the damaged holes.this is a permanent fix.you can do this job yourself.good luck.

I was reading through the replies to your problem and came across this one, this is exactly what I was going to suggest... so I second it

cth350 · #2 10-19-2008, 10:44 PM

As my friend Ron says, "nothing is more expensive than a cheap mercedes".

Well, you might as well do what the mechanic did and undo the valve cover. Then see if anything wiggles. If it does, and only for cylinder one, then you know what's wrong. After that, you'll have to read the manual a bit to get a feel for what's in front of you.

If you live in an area with pick & pulls, find a dead M103 motor like yours to experiment with and take apart the valve train to see how it ticks.

Then again, if you're not mechanically inclined, don't do that and just pass the car on or find it a used motor.

-CTH

mpolli · #3 10-20-2008, 12:25 AM

Search is your friend. Search on "300E lifter". You will find lots of threads. Genarally lifters are not "too hard" to replace but it depends on your skill level. But everyone seems to agree that is the trouble and not really a huge deal unless it goes unfixed for a while and causes cam damage as Steve said. Steve's 3rd post is what you need to know. He is usually right even though I don't understand what he says half the time.

cth350 · #4 10-22-2008, 01:55 PM

I don't have any first hand experience with this innards of this motor, but in any situation where you're considering using longer bolts, you must do two things first:

- Make sure the hole has more than room to spare. A small length of wire poked in the hole will confirm this. You really, really don't want the bolt to bottom out.

- Make sure that the bottom of the hole isn't facing something moving that a longer bolt might hit. That will be even more fatal.

Also, using a mixture of correct bolts and slightly longer ones will probably cause the next mechanic to make a mistake if (s)he's not expecting it.

-CTH

david s poole · #5 10-23-2008, 10:44 AM

cth350 do you honestly think that i would recommend an action that i had not already tried and proven?there is no speculation here i'm advising based on experience with more than one 103 engine that i have worked on for this same problem.the mechanic that tightened the bolts in the first place was probably not aware that the threads had pulled.he would have had to have had experience with this problem to have suspected this.in the holes there are 8-10mm of spare threads.if you get one that bottoms out you just use an extra 2mm of washer under the bolt head.

waybomb · #6 10-23-2008, 08:19 PM

^^^ Yup, if the bolt hole has that many threads left, I'd use a longer bolt. That's the least invasive way.

Jed89300E · #7 10-26-2008, 04:09 PM

Well, of course it's bad news. Removed the VC, and basically reached in and pulled the #5 rocker arm assembly off

. All but one bolt was broken off in the head. The top of the intake valve is beat to death and is stuck closed. Try as it may the rocker couldn't push it down and instead broke the crappy bolts the mechanic used and beat the heck out of the VC. I am assuming he used the "longer bolt" technique already

. Yay! My planned course of action is as follows:

Remove head
Take to MB mechanic and have him: a. Replace the valve. b. Extract broken bolts and re-tap threads (Helicoil?)
Replace head
Fill with synthetic oil (10W-40?)
Replace VC gasket

I need to have all the parts before I get to the mechanic. Here's my shopping list:

Intake valve
Valve guide
Valve Keeper (2 parts, looks like a wedge mbz009142)
Lifter
Valve stem seal
MB Repair Manual CD's

I am pretty sure this list is not complete. Could you all help me out in making sure I get all I need? The valve is mushroomed pretty bad at the top and will need new stuff from there down. Thee seems to be a part at the top of the spring I can't find? Also, I cant find the Rocker Arm Assembly here anywhere. Any Ideas if it turns out I need one? Any other suggestions? Thanks all for any help you can give me.

Pictures of the job will be posted as I looked here and could not find the job being done.

Thanks again for any help!
Jed