timing 4.5 sel - PeachParts Mercedes-Benz Forum

robertbrown29 · #1 08-10-2002, 09:16 PM

I just replaced the water pump on a 1972 sel 4.5 I thought I marked the distributer properly,but now the engine will not start,and it backfires through the intake.what could Ihave done wrong? thanks for any help.

suginami · #2 08-10-2002, 09:24 PM

I have found the mother of all "how to set timing on a 4.5" threads posted by stevebfl. I should get paid for this.

gas milage (1973) 450sl

MikeTangas · #3 08-10-2002, 09:48 PM

You sure you stabbed the distributor correctly? Almost sounds like it is 180* out. Easy way to tell, there should be a tick mark on the rim of the distributor (viewed with the cap off), roll the engine to TDC on #1 and the rotor should be pointing at the tick mark. If not you're off.

stevebfl · #4 08-10-2002, 10:33 PM

I remember writing that, but we have a larger problem here. We are not trying for mileage but for life itself.

To get the thing right now you will need to use Mike's advice. Short of taking off a valve cover, it is hard to tell #1 from #6. Move the engine to top dead center (TDC) and remove the distributor cap, see where the rotor is pointing. If it is pointing at #1 or #6 you will need to turn it 180 degrees. Since you marked it I presume that you have only missed by a little bit. Probably at least two teeth of the distributor gear. If you are closer to six than to one turn the motor one revolution back to TDC. You should now be closer to one than six. Lift the distributor and set it back down such that the rotor points at the #1 termional inside the cap. Notice how the position changes as the gear seats its self. If not all the way down it will be pointing wrong till it drops completely. Do this with the distributor in midrange of its adjustment and when it runs use my old instructions for getting it sweet.