Need info on the 603's chain tensioner re: oil feed - PeachParts Mercedes-Benz Forum

compu_85 · #1 08-16-2009, 12:11 PM

Calling OM603 experts: I need some information on the timing chain tensioner's oil feed.

So first a picture:

Is the "supply bore from cylinder head" pressurized? On my car the tensioner seems to empty itself after a minute or two of idling. I replaced the tensioner and the new one does the same thing, after prefilling it, installing it, running the motor, then removing it the tensioner is empty.

When I remove the tensioner there is a dribble of oil that comes out of the passage way in the tensioner's bore. Oil is getting into the tensioner, when I re-refilled the new one it turned the new oil I was using diesel oil black.

Where does that passage way get its oil from? Is there any way I can check its flow? Can cranking the engine with the tensioner removed cause the chain to skip?

Thanks,

-Jason

sixto · #2 08-16-2009, 01:26 PM

Quote:

Originally Posted by compu_85

Can cranking the engine with the tensioner removed cause the chain to skip?

Cranking without the tensioner might cause the chain to bunch up between the IP and crank. With valve clearances as tight as they are, I wouldn't do it.

Sixto
87 300D

compu_85 · #3 08-16-2009, 01:34 PM

Ok, I won't do that.

compress ignite · #4 08-17-2009, 01:05 AM

X2 on Do Not attempt start with out Tensioner installed.

Your Perceived lack of Oil in Tensioner,GSXR question.

compu_85 · #5 08-17-2009, 09:36 PM

I sent a PM to GSXR, hopefully he gets back to me soon

-J

gsxr · #6 08-18-2009, 04:05 PM

Yes, it is pressurized. There is a single bore in the block which provides pressurized oil from the oil pump, to the entire cylinder head. The feed is located almost underneath the chain tensioner, at the front / passenger side corner of the head. The head has passages which feed the oil into a galley which goes the length of the head, feeding both the cam journals, and the hydraulic valve lifters.

I assume that you're getting oil to the lifters, or it would be REALLY noisy up top! If the valvetrain is getting oil, and the tensioner is not receiving oil, it sure sounds like the oil feed to the tensioner is blocked somehow (possibly with debris from a failing head gasket). This would be pretty unusual though. When I remove the tensioner from the head, it normally dribbles oil out and makes a bit of a mess.

What are the symptoms which make you think the tensioner is emptying out? Noise, rattle, etc? Have you pulled the valve cover and observed the chain rail visually? The tensioner also has internal spring tension, which pushes the "banana" rail in as you screw the tensioner into the head...

barry123400 · #7 08-18-2009, 05:43 PM

If you think the passage is sludged up or otherwise obstructed. Try to vacuum it out. There is a chance of sludge buildup as that passsage after it leaves the head feed passage is a very low volume flow passage from what I currently understand. Lack of frequent oil changes might do it. Check the head area for evidence of sludge to verify the possibility.

Basically you want to avoid blowing whatever is in there back into the head passage. It could just move back in. Or lodge up further. My first attack on the passage would use a small tube under heavy vacuum. I would not just try to rod it out.

You cannot run the engine with the tensioner out. If you can figure out a way to apply an external pressure source to the oiling system with the tensioner out it may blow any obstruction out the tensioner end. The tensioner for all practical purposes restricts the flow in that passage normally to almost nothing.

Cervan · #8 08-18-2009, 06:43 PM

how can you tell the tensioner is losing its prime after idling? thats hard to belive since the oil pump is constantly supplying pressure to it.

barry123400 · #9 08-18-2009, 07:27 PM

Quote:

Originally Posted by compu_85

Calling OM603 experts: I need some information on the timing chain tensioner's oil feed.

So first a picture:

Is the "supply bore from cylinder head" pressurized? On my car the tensioner seems to empty itself after a minute or two of idling. I replaced the tensioner and the new one does the same thing, after prefilling it, installing it, running the motor, then removing it the tensioner is empty.

When I remove the tensioner there is a dribble of oil that comes out of the passage way in the tensioner's bore. Oil is getting into the tensioner, when I re-refilled the new one it turned the new oil I was using diesel oil black.

Where does that passage way get its oil from? Is there any way I can check its flow? Can cranking the engine with the tensioner removed cause the chain to skip?

Thanks,

-Jason

What led you to start dealing with the tensioner to start with? Chain rattle or something else?

compu_85 · #10 08-18-2009, 11:57 PM

What brought this question on is a horrible metal on metal hit sound, which sounds like its coming from the injector pump side of the engine. The sound was intermittent when I first got the car, but is now rather constant (5k miles later). It's not a continuous sound, more of a CLACK CLACK *pause* click click CLACK CLACK click CLACK click *pause*, etc. It's gotten bad enough now I don't even want to start the car.

I've replaced the vacuum pump (no change), and now the chain tensioner (no change). As I said in the first post when I removed the original and freshly prefilled new chain tensioner from the car it didn't seem like they had much oil in them, way less then after you fill it up per the FSM before installing it.

My oil pressure is good and none of my lifters make a sound. I removed the valve cover and didn't see any damage on the chain, and the rail between the cam and the IP moves freely. Looking at the top of that rail I didn't see any marks. I'm really at a loss for the cause of this sound and am getting rather frustrated trying to track it down. So much has gone wrong with this car since I got it I'm considering just dumping it now.

There is no oil in the coolant, overpressure in the cooling system, and I don't see any coolant in the oil. I didn't see any sludge anywhere... the engine only has 55,000 miles on it! FWIW when I was driving it around I was getting really poor economy, the best tank I got was 19 on the highway.

Thanks,

-Jason

Cervan · #11 08-19-2009, 12:48 AM

sounds like injectors need replaced. replace the injector nozzles and report back. i had a 616 do this exact same thing, i thought that it had a rod knock turned out to be injectors were so bad they were making a horrible knock that would go away at times.. and then come right back.

barry123400 · #12 08-19-2009, 02:37 AM

I hear your frustation. Do you know if the install of the engine was a dealer item? Have the paperwork? I think back then the replacement engines carried a fifty k warranty.

There is a ratcheting assembly in the tensioner i think. Can you install the tensioner and manualy extend it to eliminate most slack in the chain? If you go in too far you can pull the tensioner and push the piston the rest of the way through and start it back in the other end again I think. You can check that out of course first.

You should try to clear the oil passage before anything of course. If it will not clear it might be advisable to drop a personal message to a gentleman on this forum. He is a shop forman in a mercedes shop. He has vast experience.

I just do not have a good feeling about this issue since reading your last information. Hopefully that passage will clear. If the last owner had the engine installed and you can talk to him may or may not help. You want to know if he took the car back in for periodic noise once in awhile. Remermber that I am just an amateur. Not a working mechanic. I can be very wrong in my suspicions.

I really am hesitate to post this. With no real normal oil supply availble for practical purposes can the tensioner be manually set up to cover the deficiency and manually adjusted to compensate again when required. Much depends on the fineness of the ratcheting assembley if possible at all. Others hopefully can discredit what I suspect. So I believe the first priority is to find out if that oil passage is obstructed and if so can it be cleared.

Another thought was how is it possible to tell if the tensioner is full of oil or not? There seems to be a relief ball valve that acts as a pressure regulator on the inner end. On the outer end is another valve to maintain some residual pressure or prevent the fluxuating input oil pressure from dropping off.

The bright sides ? It looks like an external oil feed could be introduced to the tensioner if it was required. A quick examination of the supplied drawing indicates there is a feed passage just under the surface of the external cap on the end. The other bright spot is the size of the passages in the tensioner. Not much oil has to flow to meet it's needs. Yet it must be enough to develop operational pressure as there seems to be the equivelent of an over pressure bleed off to the crankcase at the inner end. The third bright spot is easy. It may already be functional and the noise is something else. I guess the only way to know is to check the oil passage out for proper function.

sixto · #13 08-19-2009, 03:24 AM

Injectors are easy to disqualify by loosening the injector lines with the engine running. If the noise goes away with a loose injection line, you've found the culprit cylinder.

There are moving parts in the IP timer (sprocket) but I've never heard of one going bad other than wear on the track that drives the vacuum pump. It might be worth trying a known good timer if you can find one for cheap.

Sixto
87 300D

compu_85 · #14 08-19-2009, 07:26 AM

This isn't an injector noise, at least its not like any other nailing injector I've ever heard. And like I said they have 50k miles on them... plus the car starts like a champ with no misfires at -15*F without a block heater (!). I'd think if there were bum injectors it would misfire or smoke a bunch when it was that cold... but it does not. Cold starting is the same as warm starting, it's running by the first compression stroke.

The new tensioner isn't a dealer item, but it is a Febi/Bilstein part. There is no ratcheting mechanism in either the new tensioner or the original one. Considering I'm the 3rd or 4th owner since the engine was put in I don't think there's any warranty left. The only documentation I have is a phone call to the shop that installed the engine in 2002, and the part number data plate on the bellhousing.

I'd love to try another timer, but I don't want to keep throwing $250 parts at this car. I've probably wasted $700 at this point. If someone has one they'd lend me I'd appreciate it, all the 60x engines use the same timer.

"... I guess the only way to know is to check the oil passage out for proper function."
And it looks like there's no easy way to do that

Sounds like ever other repair on this car

One possible way I see is if someone else with a 60x equipped could remove their chain tensioner (10 min job) and see if it is fully pumped up with oil or mostly empty.

"If it will not clear it might be advisable to drop a personal message to a gentleman on this forum. He is a shop forman in a mercedes shop. He has vast experience."
Who is that? I know whunter won't touch it

If I could just get it fixed and be done with it I'd be a happy man. At this point I'm considering just parting the car out as its worth more in pieces

-J

gsxr · #15 08-19-2009, 10:13 AM

Quote:

Originally Posted by compu_85

What brought this question on is a horrible metal on metal hit sound, which sounds like its coming from the injector pump side of the engine. The sound was intermittent when I first got the car, but is now rather constant (5k miles later). It's not a continuous sound, more of a CLACK CLACK *pause* click click CLACK CLACK click CLACK click *pause*, etc. It's gotten bad enough now I don't even want to start the car.

That doesn't sound like it would be related to the tensioner... loose chains typically cause a rattle noise at startup, which goes away. You are correct that the tensioner is NOT a ratchet type. I would suspect something in the vac pump area... either the pump, timer, or IP.

I assume this is not a bottom-end noise (pistons or con rods)? Does it vary with RPM or engine load? And despite the low miles, have you verified the cam timing / chain stretch, and IP timing?