Mercedes-Benz Forum banner

1 - 19 of 19 Posts

·
Registered
1985 W123 200, 1980 C107 450 SLC, 1979 C107 450 SLC
Joined
·
34 Posts
:thumbsup:

That might explain the knocking sound (reminiscent of a noisy tappet) my '80 450 makes on start up. Time to get a second opinion (form someone who isn't tone-def, like me).
 

·
Registered
'80 450SLC Afro RHD Ikonengold
Joined
·
2,900 Posts
:thumbsup:

That might explain the knocking sound (reminiscent of a noisy tappet) my '80 450 makes on start up. Time to get a second opinion (form someone who isn't tone-def, like me).
I stand to be corrected by those who heard a definitive faulty chain, I thought it should be a sound smilar to that of a bit loose motorbike chain, somewhat slapping, somewhat grinding, a bit ticking but quite distinctive from tappet noise.
 

·
R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
Joined
·
32,347 Posts
No grinding noise. A really quick rattle noise is how I would describe it. Just a second or so.
Pull the right side valve cover and check the head.
 

Attachments

·
Registered
1988 300SE Benz, 1981 VW Truck
Joined
·
36 Posts
I have a friends car in the garage, '84 380 SL with 81000 miles on it.
I remove the right v/c and lined up the sprocket mark with the pedestal mark and the crank balancer showed 8 degrees retarded. I ordered a new chain and rails. I installed the chain using Peachpartwiki thread, all went well however when I was done I lined up the marks again and the crank read 8 degrees retarded (haven't put the rails in yet). I removed the left v/c and rotated the engine and lined up the left side, the crank read 0 degrees but had to move it some more to line up the right cam (8 degrees on the crank).
Is it possible the ilder sprocket in between the cams has a bad bearing or is worn?
If I move the cam sprocket one tooth it will advance the cam too much.
Any ideas, has someone run into this before.
David J
 

·
Premium Member
1986 560SL with M120 V12 Engine, 1988 560SL Stock
Joined
·
10,209 Posts
I have a friends car in the garage, '84 380 SL with 81000 miles on it.
I remove the right v/c and lined up the sprocket mark with the pedestal mark and the crank balancer showed 8 degrees retarded. I ordered a new chain and rails. I installed the chain using Peachpartwiki thread, all went well however when I was done I lined up the marks again and the crank read 8 degrees retarded (haven't put the rails in yet). I removed the left v/c and rotated the engine and lined up the left side, the crank read 0 degrees but had to move it some more to line up the right cam (8 degrees on the crank).
Is it possible the ilder sprocket in between the cams has a bad bearing or is worn?
If I move the cam sprocket one tooth it will advance the cam too much.
Any ideas, has someone run into this before.
David J
When checking this it is very important to make sure the engine is only rotated clockwise (looking at the engine from the front) until you reach TDC. If you overshoot TDC you will have to rotate back about 20 degrees and then re-approach TDC clockwise. Good idea to also put counter clockwise pressure on the right cam shaft while rotating the crank clockwise, as the cam has a tendency to rotate ahead due to valve spring pressure.
 

·
Registered
1988 300SE Benz, 1981 VW Truck
Joined
·
36 Posts
I double checked it tonight and came up with the same results. If I keep pressure on the the right cam it would show more degrees retarded wouldn't it?
I haven't removed the timing cover and I think I am going to have too to see what is happening in there.
David J
 

·
One of the BW Old Guard/R129, W204 Moderator
1997 SL500- 40th Anniversary
Joined
·
7,166 Posts
I double checked it tonight and came up with the same results. If I keep pressure on the the right cam it would show more degrees retarded wouldn't it?
I haven't removed the timing cover and I think I am going to have too to see what is happening in there.
David J
What's the status of your tensioner? Is it extended, or collapsed?
 

·
It Is What It Is, Dude
Joined
·
22,841 Posts
I have a friends car in the garage, '84 380 SL with 81000 miles on it.
I remove the right v/c and lined up the sprocket mark with the pedestal mark and the crank balancer showed 8 degrees retarded. I ordered a new chain and rails. I installed the chain using Peachpartwiki thread, all went well however when I was done I lined up the marks again and the crank read 8 degrees retarded (haven't put the rails in yet). I removed the left v/c and rotated the engine and lined up the left side, the crank read 0 degrees but had to move it some more to line up the right cam (8 degrees on the crank).
Is it possible the ilder sprocket in between the cams has a bad bearing or is worn?
If I move the cam sprocket one tooth it will advance the cam too much.
Any ideas, has someone run into this before.
David J


Are you rotating the engine clockwise to the RH cam marks and then reading the damper scale?

MB does offer offset cam gear woodruff keys to adjust for side to side cam timing variances.
 

·
Registered
1988 300SE Benz, 1981 VW Truck
Joined
·
36 Posts
The tensioner is extended and the chain is tight.

I rotated the engine to line up the cam mark (right side) clockwise very carefully, did not have to back track then I read the scale on the damper.

I may have to go with offset keys, where can I get ahold of them?

Things will be tight for the next few days but I will see if I can get the timing cover off and take a look inside.
David J
 

·
It Is What It Is, Dude
Joined
·
22,841 Posts
Things will be tight for the next few days but I will see if I can get the timing cover off and take a look inside.

Removing the timing cover requires pulling the engine. I don't thinks those "idler" gear's bearings are the issue. Are the teeth on your cam gears excessively worn?

Dealer should have the offset keys. You can look nthem up on the EPC and check with the various online vendoers.

I'm sure the Service Manual has the correct procedure for determining which ones to use and what to do with them.
 

·
Premium Member
1986 560SL with M120 V12 Engine, 1988 560SL Stock
Joined
·
10,209 Posts
The tensioner is extended and the chain is tight.

I rotated the engine to line up the cam mark (right side) clockwise very carefully, did not have to back track then I read the scale on the damper.

I may have to go with offset keys, where can I get ahold of them?

Things will be tight for the next few days but I will see if I can get the timing cover off and take a look inside.
David J
First check to see that you don't already have an offset key installed. Keys are available up to 5° at the cam = 10° at the crank. Sounds like you may need a 4° key. Other things to check: Sprockets for wear. See if the sprocket has a part number and check it against the EPC. Check sprocket and cam key ways. Check that the current key way is not already half sheared.

Also the cam marks are only rough timing marks for assembly. Setting the cam timing rely requires a dial indicator as outlined in the engine manual. Don't worry I don't know anyone that ever does this.
 

·
Registered
1988 300SE Benz, 1981 VW Truck
Joined
·
36 Posts
Whoooh you had me worried there, I will try and pull the cam gear tomorrow night and take a look, I have to change the tensioner shoe anyways.

The gears look okay from what I can see.

Thanks for you help so far, I will let you know what I find out.
David J
 

·
Registered
1988 300SE Benz, 1981 VW Truck
Joined
·
36 Posts
I pulled the cam gear tonight and the key looks like stock so I guess I will start looking for a 4 degree off set.

Let you know how I make out.
David J
 

·
R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
Joined
·
32,347 Posts
It has been awhile but I had a similar poblem with the 4.5. I removed the cam gear and rotated the cam to line up then put the gear back on. When I rotated the engine it lined up perfectly.

According to the POS Haynes manual you can pull the timing chain without pulling the engine. That is how I got into a total engine rebuild. Luckily I had a spare TC cover cause I cracked the one on the engine. You can do it do it by removing the front suspension with the subframe.
 

·
Registered
1988 300SE Benz, 1981 VW Truck
Joined
·
36 Posts
I ordered a 3 degree and a 5 degree offset wooddrift keys and they came in last week.
I put the 3 degree on the cam and popped the rest together and checked to see how close I would be, I appears to be as close as I going to get it, possible 1 degree on the balancer.
As far as running I not sure yet as I have the FD off. I am replacing all the rubber underneath as well as all the vaccum tubing.
Thanks for all the help I found it invaluable.

David J
 
1 - 19 of 19 Posts
Top