So when I installed a new valve cover gasket a few days ago, I accidentally loosened one of the studs so that the valve cover would tighten down, but not seal; causing the car to (unnoticed) profusely leak oil. My girlfriend took the car to work yesterday and noticed on the highway the oil pressure was low. She pulled over after about a mile after noticing and the pressure she says was at about .5 at idle and at around 1 running; checked the oil and it had not run dry (slightly below the low mark). I went to her work and fixed the valve cover gasket; and, on her way home she said she noticed a tapping.

Today, I adjusted the valves to make sure none were loose, started it up and the tapping seems to be coming form the 1st cylinder valve area. The 1st cylinder intake cam lobe has some deep pitting and the rocker arm is at a slight angle (tighter on one side than the other). It's quite loud, and wasn't present just a few days ago. It sounds almost like an extremely loose valve.

I'm hoping I can get away with just a new camshaft and a new rocker arm.

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No photos of the cam yet, I haven't had a chance to go out and pull the valve cover off again. However, here is a video where you can hear the extra noise: http://www.youtube.com/watch?v=W395b1smXi4 It's much more pronounced after the 30 second mark. You can hear it clearly at 30-35", 40" and 43-48"

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'95 Geo Metro 3-cyl 5-speed
'97 Geo Metro 3-cyl 5-speed x2
'81 Mercedes 240D 4-speed manual RIP

lower oil pressure could cause some damage... but.. whether or not your cam damage was done by the low oil or not I dont know. easy way to check is to drain the oil and look for metal especially if the damage is recent

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hum.....
1987 300TD 311,000M Stolen. Presumed destroyed

If getting a used cam remember that every used rocker that rode against those lobes in the donar car should be reinstalled on the same cam lobes. They establish an individual wear pattern that should not be disturbed.

Also inspect each rocker for any evidence of wearing through the hardened surface over time. This fortunatly is unusual on these particular mercedes engines.

Find out if there was a cam change when mercedes boosted the power in the 616. It also sounds very much like you did loose the upper oil feed.

Typically on mercedes for some reason the first cam lobe on their straight layout engines seems to be the most subject to problems. Much more pronounced in their gas engines before the seventies. Coincidence is not too likely here in my opinion other than the cam lobe may have had some pre existing wear present and just got pushed over the edge.

OK, so the camshaft has a "10" stamped on it; guess I have the newer camshaft. I was able to snap some photos as well:





Looking at it, it almost looks as if the 1st cylinder exhaust rocker is slightly bent rearwards. The clearance between the camshaft and the valve is also noticeably tighter toward the front of the engine on the 1st cylinder exhaust rocker. I suspect that is what has caused the noticeable damage. Think I could just get away with replacing the bank of damaged rockers?

Attached Thumbnails

     

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'95 Geo Metro 3-cyl 5-speed
'97 Geo Metro 3-cyl 5-speed x2
'81 Mercedes 240D 4-speed manual RIP

-bump-

Anyone think I could replace just the front bank of damaged rockers while leaving the rears intact?

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'95 Geo Metro 3-cyl 5-speed
'97 Geo Metro 3-cyl 5-speed x2
'81 Mercedes 240D 4-speed manual RIP

Not really- You should replace the cam and all the rockers as well if that rocker is actually riding on that damaged area. It looks like the hardened surface has been worn away, which means the rest of that lobe will be gone shortly. More of an age-related thing than a sudden damage.

OK, so i finally got around to replacing the cam & rockers. Reassembled everything and double checked the timing; fired it up after cranking for a minute to refill the fuel lines and it seems like it is idling really smooth! Take it out of the garage and the tapping resumes, drive it down the street to see if it'll get better and the tapping seems to stay about the same. No loss of power, just a very loud tapping. It seems to be getting louder the more the car is run. Any ideas of where to start looking? I hope to get a video uploaded soon.

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'95 Geo Metro 3-cyl 5-speed
'97 Geo Metro 3-cyl 5-speed x2
'81 Mercedes 240D 4-speed manual RIP

Did you drain the engine oil and inspect it for debris?

If at running rpm's your oil gauge did not get under one this may not be oil pressure related. That is according to the FSM...
When you changed your oil last.. did you see that the tube down the middle of the oil filter.. the one attached to the top... had the hole open and new orings on the bottom of it ?

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

I did not. That would of been a good idea.


I don't recall if the tube had the hole open, i'd have to assume it did. But I'm really not sure.

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'95 Geo Metro 3-cyl 5-speed
'97 Geo Metro 3-cyl 5-speed x2
'81 Mercedes 240D 4-speed manual RIP

It is a small hole...but very important....
How is your oil pressure now that you have the level back up to normal ( which should be half way between min and max on the dip stick to avoid excessive oil usage).
The FSM ( I believe the 616,Na617 FSM ) mentions the potential for the oil pressure valve on the backside of the oil pump being faulty and causing noises.. although from memory I thought they referred to noises at start up.. but even so... there are several models of that oil pressure valve...different designs... and you might want to check to see 1. if it is loose 2. if you have the latest recommended design for your engine..
On that oil hole...often burnt caked oil and varnish in a very small hole.. I use Safety Wire ( very strong ) long enough to reach the distance, tap the end to make a drill end and turn it with a battery operated drill... might have to shim as some drills do not clamp that small....and allow it to sit with a solvent in it... before and after... and ONLY WITH GOGGLES AND FACE MASK ON blow it out with compressed air... the o rings are usually so hard they appear to be metal... a knife pressed on them causes them to shatter....and generic o rings can be had at a local hardware store... info in the archives on this...
The oil flow from the pump comes in from the bottom.. you have sealed up the top and thus... you need this hole to allow the air trapped in the oil filter canister to vent for filling with oil...

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

the noise may not be from the head

The pressure is fine now that there is oil in it.


That is definitely what i'm concerned about. I'm just having trouble pinpointing where the sound is coming from

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'95 Geo Metro 3-cyl 5-speed
'97 Geo Metro 3-cyl 5-speed x2
'81 Mercedes 240D 4-speed manual RIP

unfortunately it could be big end/crank bearing related even with normal oil pressure

Would there be any way to diagnose that with the engine in vehicle?

__________________
'95 Geo Metro 3-cyl 5-speed
'97 Geo Metro 3-cyl 5-speed x2
'81 Mercedes 240D 4-speed manual RIP