How to get the correct Ignition Timing?
Thread Starter
Newbie
Joined: Feb 2011
Posts: 2
Likes: 0
From: Atlanta, GA, USA.
1991 300se
How to get the correct Ignition Timing?
Hey all,
I recently changed my Head Gasket, Manifold gasket & Exhaust gasket on this car with 182K miles on its 103.981 engine which had developed oil mixing in the coolant problem, i.e., a typical sign of bad head gasket. Since I was doing all this, I also changed the old timing chain with a new one.
During the timing chain installation, I carefully aligned the positioning bore of the camshaft with the marking on the 1st camshaft bearing and also positioned piston of No. 1 cylinder to TDC ( AS PER THE INSTRUCTION ON THE SERVICE MANUAL).
Now during tightening of the chain tensioner to the required torque, I noticed that the camshaft marking moves slightly off to the left ( as viewed from the front of the engine). I tried many manipulative ways, e.g., kept the camshaft marking slightly off to the right before tightening, but to no avail.
When I crank the car up, it doesn't starts and misfires.
Can someone who knows what Iam talking about help me resolve the problem and get this baby crank up like it use to do before.
Thanks in advance for all your help & support.
Truly
KKSinha
I recently changed my Head Gasket, Manifold gasket & Exhaust gasket on this car with 182K miles on its 103.981 engine which had developed oil mixing in the coolant problem, i.e., a typical sign of bad head gasket. Since I was doing all this, I also changed the old timing chain with a new one.
During the timing chain installation, I carefully aligned the positioning bore of the camshaft with the marking on the 1st camshaft bearing and also positioned piston of No. 1 cylinder to TDC ( AS PER THE INSTRUCTION ON THE SERVICE MANUAL).
Now during tightening of the chain tensioner to the required torque, I noticed that the camshaft marking moves slightly off to the left ( as viewed from the front of the engine). I tried many manipulative ways, e.g., kept the camshaft marking slightly off to the right before tightening, but to no avail.
When I crank the car up, it doesn't starts and misfires.
Can someone who knows what Iam talking about help me resolve the problem and get this baby crank up like it use to do before.
Thanks in advance for all your help & support.
Truly
KKSinha
Senior Member
Joined: Oct 2004
Posts: 272
Likes: 3
From: Michigan
SL600 r230, SL600 r129, SL500 r230, ML320, C280 Sport, R170 450SL, 190e 2.3 16V (2)
Not sure on these engines, but is it possible you've done everything correctly, but now have the distributor rotor 180 degrees out?
The rotor should be pointing to #1 wire position with cylinder TDC and both valves closed.
The symptoms you describe are the same as if the rotor was out 180 degrees, meaning, rotor at #1 wire, piston TDC, and probably both valves open for the exhaust/intake overlap.
I have no advice otherwise, as I've never had to do the job you've just perfromed.
The rotor should be pointing to #1 wire position with cylinder TDC and both valves closed.
The symptoms you describe are the same as if the rotor was out 180 degrees, meaning, rotor at #1 wire, piston TDC, and probably both valves open for the exhaust/intake overlap.
I have no advice otherwise, as I've never had to do the job you've just perfromed.
Member
Joined: Oct 2007
Posts: 119
Likes: 0
380se
Had the 180 prob. many many times. Seems like that is the only way I know how to install a distrib, 180 first, nothing works, and then correctly.
I assume you have the service manual? You looked at the pics closely? I have also never done this job but have swapped many cams. There is always what seems like a little slop in the cam alignment to the dots, but it is never much < a few degrees.
I assume you have the service manual? You looked at the pics closely? I have also never done this job but have swapped many cams. There is always what seems like a little slop in the cam alignment to the dots, but it is never much < a few degrees.
Senior Member
Joined: Jun 2006
Posts: 303
Likes: 1
From: Northern California
It changes all the time
To answer your first question about valve timing being off slightly, the machinist must have taken quite a bit of meat off the head. The distance between the cam gear and crank year is now shorter and can only be corrected within offset key. If it is only off a slight amount, I wouldn't worry about it, because to reset timing within offset key is quite complicated.
As to ignition timing, there is no way that you can screw that up. The distributor and rotor are slapped on to the front of the head, and you just cannot install it incorrectly. Timing is determined by the crank position sensor on the flywheel and the value of the resistor that controls the ignition module.
I cannot tell you why the car won't run or start without seeing it.
As to ignition timing, there is no way that you can screw that up. The distributor and rotor are slapped on to the front of the head, and you just cannot install it incorrectly. Timing is determined by the crank position sensor on the flywheel and the value of the resistor that controls the ignition module.
I cannot tell you why the car won't run or start without seeing it.
Member
Joined: Oct 2007
Posts: 119
Likes: 0
380se
Good to know that it can't be done wrong. My exp is with small block chevy engines. I always lined up the timing mark for 0TDC on what i thought was the compression stroke for #1 and would then fight the distributor gear into the toothing on the cam and trying to keep the rotor lined up (mostly) to the #1 plug position in the distrib. This sometimes a little bump on the started would pull it right down. My problems always came in that I would end up with the exhaust stroke rather than the compression stroke. Not sure why I always screwed this up, but like I said, my history is 180 out first, and then right on the next pass.
I have often pondered pulling the distrib on my benz but have fought the urge due the fact that it did not seem to be totally necessary to accomplish what I was doing and my previous experience fighting with getting them installed.
I have often pondered pulling the distrib on my benz but have fought the urge due the fact that it did not seem to be totally necessary to accomplish what I was doing and my previous experience fighting with getting them installed.
Senior Member
Joined: Jun 2006
Posts: 303
Likes: 1
From: Northern California
It changes all the time
elolson,
I don't want you to get confused about my statement on distributors. The original poster is inquiring about an M103 engine. I see by your post that you have a 380 SE which would have either an M116 or an M117 engine. They are two completely different animals. The distributor in your car is pretty much the same as that small block you are talking about. As I said the original poster's car has a distributor slapped on the front of the head with notches for assembly. There is no way to screw that application up.
I don't want you to get confused about my statement on distributors. The original poster is inquiring about an M103 engine. I see by your post that you have a 380 SE which would have either an M116 or an M117 engine. They are two completely different animals. The distributor in your car is pretty much the same as that small block you are talking about. As I said the original poster's car has a distributor slapped on the front of the head with notches for assembly. There is no way to screw that application up.
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Newbie
Joined: Aug 2010
Posts: 4
Likes: 0
Mercedes s550
Hey all,
I recently changed my Head Gasket, Manifold gasket & Exhaust gasket on this car with 182K miles on its 103.981 engine which had developed oil mixing in the coolant problem, i.e., a typical sign of bad head gasket. Since I was doing all this, I also changed the old timing chain with a new one.
During the timing chain installation, I carefully aligned the positioning bore of the camshaft with the marking on the 1st camshaft bearing and also positioned piston of No. 1 cylinder to TDC ( AS PER THE INSTRUCTION ON THE SERVICE MANUAL).
Now during tightening of the chain tensioner to the required torque, I noticed that the camshaft marking moves slightly off to the left ( as viewed from the front of the engine). I tried many manipulative ways, e.g., kept the camshaft marking slightly off to the right before tightening, but to no avail.
When I crank the car up, it doesn't starts and misfires.
Can someone who knows what Iam talking about help me resolve the problem and get this baby crank up like it use to do before.
Thanks in advance for all your help & support.
Truly
KKSinha
I recently changed my Head Gasket, Manifold gasket & Exhaust gasket on this car with 182K miles on its 103.981 engine which had developed oil mixing in the coolant problem, i.e., a typical sign of bad head gasket. Since I was doing all this, I also changed the old timing chain with a new one.
During the timing chain installation, I carefully aligned the positioning bore of the camshaft with the marking on the 1st camshaft bearing and also positioned piston of No. 1 cylinder to TDC ( AS PER THE INSTRUCTION ON THE SERVICE MANUAL).
Now during tightening of the chain tensioner to the required torque, I noticed that the camshaft marking moves slightly off to the left ( as viewed from the front of the engine). I tried many manipulative ways, e.g., kept the camshaft marking slightly off to the right before tightening, but to no avail.
When I crank the car up, it doesn't starts and misfires.
Can someone who knows what Iam talking about help me resolve the problem and get this baby crank up like it use to do before.
Thanks in advance for all your help & support.
Truly
KKSinha
Thank you
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