W123 Cam Timing Help!!
 

Just purchased another w123 300D. The car was not running as the owner had started a cam chain replacement, dropped the chain, and gave up. Well, to make a long story short, I bought the car and fished the cam chain out (amazingly it was still around all of the sprokets). So here goes, the timing marks on the cam tower and sprocket line up with the balancer, but it doesn't seem like they do on every rotation??? Could this be true, or am I missing something? I just rotated it, hit dead on zero on the balancer. Rotated it again, way off advanced, rotated again, way off retarded. Am I missing something here? This is my first time playing around with this, so any help would be appreciated. The car "seems" to turn over okay with no noticbale binding. How do I get this thing back so I can fire 'er up?

Cheers

Jeffrey

You will want to do this with the cam cover off.
Put the engine at TDC as indicated on the crank. Look at the cam lobes on the #1 piston. If they are pointing more away from the piston you are at TDC on #1 cylinder and the cam marks should be lined up along with the balancer mark. At this same time the #5 piston is at TDC BUT not on the compression stroke. Now turn it over until the crank balancer mark is lined up and look at your cam lobes. The #5 piston cam lobes should be pointing AWAY from the piston like the ones on #1 were previously. This is TDC compression on #5. Your cam marks should not be lined up at this time. The fact that you can turn the engine over is an indication to me that you are probably in pretty good shape.

Thanks for the reply. Now I'm really confused. So, if the balancer, camshaft and tower mark ALL line up at some point, I should be okay? I'm getting very anxious about actually starting it, so, I just want to be sure that I'm not going to hear those terrible noises....... But yes, I have rotated the engine a number of time with no clanking.....


Okay, here is what it looks like with everything lined up.

first lobe (lookking from front) is close to hoirzontal pointing right
Second lobe is at about a 45 degree angle to the left.

Cheers

On an american car, and including the german made 2000cc for Ford, if ALL the dots line up you have a winner. Every cam gear and every chain and/or gear I have replaced, the notches have to line up exactly. Becareful, you can be one tooth off and it can change the timing by as much as 10 degrees or more! The cam gear should have a dent in it or an arrow, same with all others gears.
That is the beauty of Pete Jackson gears, you can only be right on or 180 degrees out, either way will start up!

You are missing something very important here. In the case of this engine, you ALSO need to time the injection pump.

With the balancer in the right position (23 degrees before I think) the camshaft in the right position with the cam and tower mark in the right position, the number one position on the pump should be dripping once per second. You need a drip tube, which is very inexpensive, to see that the pump is also correctly timed.

As for the position of the cam lobes, I would have to pull a valve cover to check for sure.

Don't overlook the IP timing.

Good luck,

Oh yea, like LB says - don't forget the IP timing :).
The fact that you can turn it over by hand without anything hitting is a good thing.

One other thing to remember on cam timing. The crank has to turn two revolutions for every one revolution of the cam. The first lobe on the cam (closest to the chain) should be pointing up to the right, the second lobe on the cam should be pointing up and to the left. This is Cyl #1 on the top of its power stroke. You will have to remove the oil filter canister to remove the injection pump (Someone correct me if I'm wrong, but I've never been able to get the injection pump out of the way without moving that first).

1979 300D is 24 deg before top dead center on the injection pump timing. I'm pretty sure turbos are 25 degrees.