Oil tubes - PeachParts Mercedes-Benz Forum

pcsessler · #1 03-24-2009, 02:14 PM

I have a 1992 MB 500SL and I am trying to eliminate problem areas- I replaced all the timing chain guides, oil pump and idler gear. When I got the car back, it wasn't idling as smoothly as when it went to the shop.

I took my valve covers off, but I found that the oil tubes in mine are made of aluminum. They are sort of lose and seem to move around, up and down, on the seal that is on the tube. Is this "normal"? Should I change the seals?

I like the idea of having aluminum ones, based on stories from other owners- by the way, the aluminum ones have a small ball at the end (pointing to the exhaust valve).

My car revs to about 3200 rpm and then really loud noise happens-lots of valve noise. The noise also happens at around 1500 rpm or so but a bit quieter- and it has gone away by itself.

Oil pressure: at idle, it really goes down below 1 bar; it cruises at 3 fine. I use 10W-30 Mobil 1.

I took the car to a reputable Mercedes tech- he recommends checking the timing (he feels it is incorrect), then check for a bent exhaust valve. He feels he has to get into the timing chain area to proceed.

Thanks!

pcsessler

rocky raccoon · #2 03-25-2009, 06:37 AM

are the cam oilers and are important to keep in good shape. Since you have the cam cover off it is a simple and inexpensive job to replace the plastic clips that hold them in place and bring oil to the tubes.

Pry out the old clips carefully so they don't break off and press in the new. Clips should be less than $1.00 each.

Your oil pressure is bothersome. I have an M117 engine and my oil pressure at cold idle pegs at 3 bars. After fully warm it may drop to 2.5 bars but I have never seen 1 bar. It may be a result of a different engine or choice of oil weight. Your pressure combined with your engine noise would have me looking deeper.

pcsessler · #3 03-25-2009, 04:28 PM

Thanks for the info.

I took off the other valve cover- it looks the same as the other cover.

As I don't have plastic oil tubes (I have metal ones) they all look OK- not broken or bent. I've decided to replace the "O" rings on the tubes- but I doubt that they are the problem.

Next I'll have our mechanic (I have a friend who owns a Used Car Lot) take off the accessories that cover the timing chain. Something is not right. Perhaps the previous mechanic (he returned the car in this condition) left something off(?)- in any case, our mechanic will set the correct timing, and check the valves for straightness. And then I'll have a MB mechanic come over and see what he says.

pcsessler

Steve Gutman · #4 03-25-2009, 11:04 PM

I had a timing chain replaced and then after had some drivability problems. A local mechanic said he wanted to check the timing for $150. I asked him how and he said he would line up the timing marks. The Mercedes are checked by installing an adjustable lifter in #1 cylinder and taking it to 2mm lift and checking the mark on the flywheel. Something like that, I would have to check the book but I changed the fuel injectors the idle and smootheness were great. I never changed the timing.

The timing is adjusted as above then by using offset keyways in the camshaft they can be independently adjusted. It can be set just right but it is a lot of labor and a very specific process. You may also have some lifters that need shimming or replacement.

Get the manual on CD ROM for your mechanic to check out if he doesn't know the Mercedes.

pcsessler · #5 03-25-2009, 11:32 PM

Thanks- I know the MB timing is specifically difficult- I'll ask the MB mechanic to set the timing. That's the plan, at least.

pcsessler

pcsessler · #6 05-01-2009, 09:29 PM

Hi,

I just want to bring everyone upto date.

1. I decided to do the work myself- the first step was to do a compression check on all the cylinders- the reading was 150 lbs.+ so that means the valves are ok and not bent, or burnt. I kept the spark plugs out as it made the whole process easierl

2. Set the harmonic balancer at 45 BTDC and then inserted the four pins into the first cam rockers- I got a length of tubing at a hardware store and made the four pins. Since I didn't have the cam adjusting tool, I trimmed an extra set of vice-grips so they work just as well. With the four pins and the balancer set at 45, I turned by hand (actually a large ratchet) the balancer and everything was the same timing four turns later. Then I reinstalled the timing chain guides, timing chain tensioner, alternator, air pump, belt, and valve covers.

3. Car now runs fine- no noise. All that noise was due to detonation- half the engine was fighting the other half as the timing was way off. Oil pressure now, using Mobil 1 10W-30 is 1 bar at idle (around 600 in gear) and 3 at higher rpms.

4. I decided to JB Weld the oil tubes- I first replaced all the "O" rings, cleaned all the oil off and then using JB Weld, glued the oil tubes in place so no oil can get by. I didn't like having the oil tubes moving around and so far, everything is fine. According to the JB Weld people, the stuff is good to 500 degrees.

5. That's my story!

Peter

duxthe1 · #7 05-01-2009, 11:16 PM

Don't take it personally, but the JB weld was way overkill. That engine would have run fine for the rest of it's useful life with the original o-rings. The up down movement is normal if you fiddle with them and new ones would do the same thing except for the extra tension of a new o-ring. In a running engine they are held stationary by the oil pressure. Myself, I'd be more worried about bits of JB floating around in my engine