1984 190D Timing Chain has slipped... - PeachParts Mercedes-Benz Forum

iamtheosprey · #1 02-06-2015, 01:56 PM

...in the middle of a head gasket replacement.

I know this because the mark I made on the chain to align it with the cam gear is way off TDC now that I am trying to get it all back together.

If any of you have experience with getting the timing right on this engine please chime in.

I have heard that I should remove the vacuum pump.

I haven't yet done this and will wait to proceed until I get some good guidance on the matter.

I do have the FSM for this engine.

iamtheosprey · #2 02-06-2015, 03:10 PM

It looks like my marks do line up but I apparently made them when the engine was NOT at TDC.

I'm not sure how or why that happened but that appears to be the case.

As long as I put the crank where my marks on the chain and cam gear as well as the marks I made on the cam relative to the mark on the front bearing cap line up should I be OK?

I'm increasingly convinced it would be very difficult for the timing chain to actually slip.

I think I'll proceed as though my assumptions are correct....wish me luck...

tjts1 · #3 02-06-2015, 03:34 PM

You're right the chain is virtually impossible to slip so long as you have the cam gear zip tied to the chain. Remove the vacuum pump. The vacuum pump spring will will pull down on the timing chain. If you hold on tightly to the cam gear you can pull it back but its best just to remove it. Also if you haven't already done so, unscrew the tensioner most of the way outl. This is based on experience with the om603 which is virtually identical in configuration to your OM601.
good luck

Maxbumpo · #4 02-06-2015, 03:42 PM

It is really not that big of a deal. As already said, remove the vacuum pump, and I prefer to completely remove the chain tensioner.

Put the crankshaft at TDC. Install the cam shaft with the timing mark lined up with the cam bearing tower timing mark. Install the camshaft gear, moving the chain around on the gear as necessary.

Once you think you've got it all together properly, install the tensioner (don't forget a new seal ring), and then rotate the engine by hand through at least two completed revolutions of the crank (one complete revolution of the camshaft). Immediately stop if you encounter any abnormal resistance - you probably have a valve touching a piston.

If the timing marks on the cam/bearings lines up with TDC on the crank (or at least within 5 degrees, assuming your timing chain is not worn out), then you've got it right.

iamtheosprey · #5 02-06-2015, 10:45 PM

I managed to find a way to complicate things.

The keeper for the cam managed to come out of it's slot and I'm pretty sure it ended up in the crank case via the timing chain enclosure.

I have cranked the engine around once so far and no binding occurred.

How likely do you think it is that this piece ended up in the oil pan?

If not the oil pan, where else is it likely to have settled.

Like I said, I don't think it's anywhere it would cause the timing chain or anything else to bind.

Stretch · #6 02-07-2015, 03:43 AM

Quote:

Originally Posted by iamtheosprey

I managed to find a way to complicate things.

The keeper for the cam managed to come out of it's slot and I'm pretty sure it ended up in the crank case via the timing chain enclosure.

I have cranked the engine around once so far and no binding occurred.

How likely do you think it is that this piece ended up in the oil pan?

If not the oil pan, where else is it likely to have settled.

Like I said, I don't think it's anywhere it would cause the timing chain or anything else to bind.

I think it is probably time to remove the oil pan - at least there's a lower pan and not (like the M102) a pan that goes along the length of the whole engine...

iamtheosprey · #7 02-07-2015, 10:57 AM

Quote:

Originally Posted by Stretch

I think it is probably time to remove the oil pan - at least there's a lower pan and not (like the M102) a pan that goes along the length of the whole engine...

What if it's just trapped in the timing cover?

I also figured that since the timing cover is easier to remove than the oil pan on this car I might be able to fish it out of the oil pan with a magnet if it did fall that far.

Stretch · #8 02-09-2015, 04:41 AM

Quote:

Originally Posted by iamtheosprey

What if it's just trapped in the timing cover?

I also figured that since the timing cover is easier to remove than the oil pan on this car I might be able to fish it out of the oil pan with a magnet if it did fall that far.

Well I don't know - you'll have to fish about and see. Good luck.

Maxbumpo · #9 02-09-2015, 01:24 PM

On my OM603 and OM606, on the passenger side of the oil pan, there is a "extension" of the pan to add additional oil volume. Removing said extension reveals a nice opening into the pan about 1.5 inches by 6 inches or so (from foggy memory). Does your pan have something similar, or maybe a plate covering that opening?

Removing the timing case is a bit of a pain, and then how will you make sure you get it flush with the block at the head? On the other hand, you will be able to replace all those chain guides. I think you will also have to replace the front crank seal?