my cams all have off center points on the lobe, should I be worried - Page 2 - PeachParts Mercedes-Benz Forum

JimmyL · #16 03-10-2010, 08:59 PM

Heck, just adjust the valves and perform your regular maintenance. Unless you want to rebuild head and replace cam. No use doing that until you have to......

barry123400 · #17 03-11-2010, 01:13 PM

Go to a company on the web like crane cams and ask them the question. The increased amount of noise you quote may be an issue. For example it may be causing stress somehow by having the irregular lobes. People who specialise in cams may know something that we do not for example.

Fortunatly if they suggest for whatever reason there is a potential issue with this. Good used cams and their lifters are still almost a dime a dozen for these cars. If they were to tell you it is not a serious issue either it will reasure you.

whunter · #18 03-11-2010, 01:19 PM

Quote:

Originally Posted by dropnosky

this pic kind of shows it pretty well, the discolored area is a sharp point on the cam lobe. All of them have this, is it stock? or odd wear?

when running, there is a lot of top end noise from this motor. I don't think the valves have been adjusted within 100,000 miles, maybe not ever. this is an 85 617

I need more pictures for an opinion on this cam.

Have a great day.

barry123400 · #19 03-12-2010, 01:10 AM

The more I think about this the stranger it is. If it were just one lobe I might allow material defect for it. The peaks are there because of the flat spot just before them I assume. I am also having some difficulty with the obvious discoloration indicating heating there. I also wonder if there is also a flat spot right after the peak.

As Hunter said can you get a better close up? A lot of digital cameras have a macro mode to remain in focus very close up. Actually a closer parellel shot along the lobe face would also be helpful. I just do not know if one is possible.

jt20 · #20 03-12-2010, 01:31 AM

I have seen this before. It is only on the forcing side of the lobe. There is a flat spot just before the apex of the lobe.

FSM suggests there was an issue before some "chilled iron" upgrade, but I have seen this on later turbo models.

JB3 · #21 03-12-2010, 09:02 AM

Ill try and take a better pic, the cam itself is actually not discolored, thats just from my worklight.

I was trying to find an angle that would allow the point to illustrate itself.

This was part of my confusion of whether its by design, because all exhaust and intake valve lobes have almost the exact same point on them. Sounds like definitely not by design from what you all are saying, and probably an indication of larger issues possibly.

Just to note, this engine has barely run in my ownership, it was running when I came to inspect if it ran, then It took about 6 hours to get it started so I could drive it home the next day, and it started to overheat, so I had it towed. Then it took me almost an entire day to get it started again to get into the garage.

The engine started much more easily with the block heater, and the fuel delivery issues solved up to the lift pump and a new primer pump, but it runs with a lot of clatter and top end noise. I was hesitant to let it run too long as there are major cooling system issues.

Im debating on sourcing a new engine that I know works properly for the interim so I can get the car rolling, and pulling this one out so I can rebuild it. It leaks so much oil that the oil leaks alone could be easily fixed while out. Whats stopping me so far has been I have not tested the compression properly yet. A tester is coming in the mail.

jt20 · #22 03-12-2010, 01:50 PM

its worth noting that the later model 60x engines have a much more 'rounded' cam profile.

whereas these engines have very straight edges on each side of the apex.

If the flat spots ever worry you to the point of replacement, seriously consider the replacement of the rocker arms as well.

The rocker arms are more prone to wear considering their very narrow contact are with the cam. If anything, the rockers flatten out first, then transfer it to the cam on the highest stress area.

JB3 · #23 03-12-2010, 03:04 PM

well, adjusted the valves, received my compression tester (mailed down for me from my toolbox by a friend) and I have some low compression problems with this motor.

Ive decided to pull it and replace it for now since the car needs to be road worthy soonest. Ill tear it down on a stand for later rebuilding.

moon161 · #24 03-12-2010, 03:36 PM

Where in CNY?

Is that 300TD as in wagon or as in rogue T?

Some have luck w/ marvel mystery oil unsticking rings & helping compression.

What are the compression #'s?

JB3 · #25 03-12-2010, 05:02 PM

Actually the cars down in CT, but I live in Syracuse, where the car will live when in done screwing with it, couple hundred miles from you I think, like 200 or so?

This is an actual wagon, not a rouge T! God help me if I were to make that mistake after reading some of the reactions on this forum!

A non SLS engine will work as I have removed most of the broken SLS system. Ive got some heavier springs to replace all that stuff. Review on that to come.

Compression is below 250 on the first three cylinders, and above 320 or so on the last two.

I will try the marvel oil when I have it out, but actually im pretty excited about rebuilding it now, it sure leaks enough oil to need a lot of gaskets and seals as well, so maybe this will be next winters project.