1985 W107 500SL M117.960/2 cam question - PeachParts Mercedes-Benz Forum

BBAY · #1 10-31-2002, 06:35 PM

Hi all...first posting.
It seems that I have a worn lobe on right cam on this Euro 5 litre V-8. Various source both here and in Europe I.D. part number as either 117 051 0901 or 117 051 0301. Questions:
1.Does anyone know with certainty the correct number?
2. In lieu of replacing cam is weld up and reprofile an option?
3.Is the change out of cam and associated rocker a job that can be performed without specialized tools?
4. Where can I find procedure?
Thanks
BBAY
w107 500SL 1985
W198 300SL 1963

psfred · #2 11-02-2002, 12:11 PM

This is the "hot" 051/052 cam set -- any 051 cam should fit just fine, although I'm sure if I'm wrong that someone else will pipe up.

Cam is fairly easy to change on this engine EXCEPT for the angled bolt on the rear cam tower. Right is better than left, but is often impossible to remove the bolt with the cam tower in place, they must be removed together.

DO NOT switch left and right rear towers, you will get oil starvation and another ruined cam. Replace the plastic "drip" line and fittings when you replace the cam, you will surely break the old ones. Verify that you have oil dripping onto the cam before running the engine at road speed.

Peter

BBAY · #3 11-02-2002, 03:08 PM

PETER: Thanks for the tip. Until I get time to determine the correct cam and replace it, I just replaced the worn rocker. In exchange for a case of Bitberger Ale, the local M-B miester gave me a rocker, valve cover seal and use of a valve spring compressor for an hour. Best deal I've made recently. No more tap tap tap.
Regards
BBAY

stevebfl · #4 11-02-2002, 04:05 PM

Check the end of the cam, there will be a two diget number stamped into it. Those two digets are the second to last two digets in the part number. Ex: 09 would be what would be found on the back of cam # 117 051 09 01.

ctaylor738 · #5 11-02-2002, 08:42 PM

FWIW: according to the CD, the "03" cam is the "hotter," opening the intake at 12 deg. ATDC, as opposed to the "07" at 22 deg.

BBAY · #6 11-02-2002, 09:09 PM

Thanks, Chuck. What I found odd is that Mercedes (niether U.S. or German) wasn't able to tell me what was SUPPOSED to be in this engine when provided with both the VIN and engine serial numbers. I had always thought that with these numbers they could tell you whether the final inspector had mustard on his brat that day (;-).
BBAY
W107
W198

Kebowers · #7 11-03-2002, 09:04 AM

If you can stand the down time, the best option is to have the cam repaired. Not a big deal for the right shop. That way you do not have to replace all the followers--just the one on the repaired lobe.

BBAY · #8 11-03-2002, 10:24 AM

I don't know whether D-B's design of the valve train intentionally made the rockers sacrificial elements, but that seems to be the case. Differences in the level of case hardening of the lobes and rockers leave the lobes dimensionally close to standard while the rocker contact faces wear more rapidly. Though there are striations in the cam lobe contact area, just replacing the rocker returned the lash to an acceptable level....for now.
Thanks
BBAY
'63 W198
'86W107

ctaylor738 · #9 11-03-2002, 12:39 PM

You might want to go through the pre-load check on the ball studs on that side of the engine to see if the adjuster on the valve that caused the problem is out of spec. You might be able to head off future problems.

If you were able to get all that for a case of Bier, then for another you should be able to take the little measuring tool and a valve spring compressor home for the weekend.

E-mail me if you want a soft copy of the procedure.

Here is an example of maximum damage to a rocker - this one came out of my "road kill" 380SL.

BBAY · #10 11-03-2002, 03:02 PM

Chuck:
Ouch! That rocker looks rather sick. I don't mind the case of beer as much as the long drive to get the tool. I am going to fabricate one. The pic is one that I missed on ebay yesterday. I wish I had bothered to sketch the dimensions when I had the factory one for that hour the other day, but it doesn't seem the it is a dimension critical device. The other tool for measuring valve lash sound a bit more sophisticated. Can this be accomplished with a dial indicator?. I would be interested in the procedure, as the only manual I have is a Chilton's, which is pretty vague.
Thanks for the info and assist.
BBAY
Bruce Baysinger
'63 W198
'85 W107

stevebfl · #11 11-03-2002, 03:27 PM

Yea, Chuck sent me that rocker arm and I keep it on my desk for grins. It is a magnitude ten worse than anything I have ever seen before.

The first picture that clearly shows a line across the face of the rocker pad is just getting to the point where it will take out the cam lobe. As soon as the line gets deep enough to go through the hardening both it and the cam will be history. It will have been noisy for some time.