Timing and plug wire location? - PeachParts Mercedes-Benz Forum

JBR · #1 03-20-2006, 05:14 PM

73 450sl- I still can not get 5*atdc. I am wondering if the wires are on the wrong plugs.
1st question- Spark plug location, Is this correct? Passenger side front plug is #1 cly. Next is # 2 and so on till the back passenger side plug is # 4 cyl. Then on the drivers side, front plug is # 5 cyl and going to # 6 and so on till #8 cyl is back plug on drivers side.

Next- Looking at the dist cap. Plug wire to #1 cyl is on the post at 1:00. going clockwise around the cap what cly wire goes next about 2:30 and so on. any help please Thanks

autozen · #2 03-21-2006, 12:31 AM

Your cyl numbering is correct. Pull the dist cap. A small line on the edge of the dist housing marks #1 cyl. The dist rotates CW. The firing order is cast on the topside of the valve covers. It says: ZUNDFOLGE. You can check for #1 by removing the right bank valve cover and checking for rabbit ears.

JBR · #3 03-21-2006, 06:08 AM

Thanks for the help Autozen: If I understand you correctly.
Firing order 15486372
Looking at dist. cap (1:00) is #1 cyl now going ccw (11:30) should be #5 cyl plug wire. still going ccw around the cap (10:00) would be #4 cyl plug wire. and so on. If this is true, mine is not even close. This could be why I can not time it to 5*atdc. What do you think. Thanks

autozen · #4 03-21-2006, 10:24 AM

If that is the firing order you got off the valve cover, then that is correct. I don't know the firing order from memory. The dist turns CLOCKWISE. You can pull the cap and ground the high tension lead from the coil to protect the ignition module and have someone crank the car. You will see the dist rotate CW and you will see a little line on the edge of the housing that looks like it was made with a chisel. That should be #1 if it hasn't been screwed with. TIP: I made a spewcial tool that I did not give an MB part # to. I fashioned a coat hangar to hook into the dist cap and into the metal stiffener at the firewall end of the hood. That keeps the SOB out of the way while you are working on the dist.

JBR · #5 03-21-2006, 11:17 AM

Maybe I am not correct. In my discription on how to locate the plug wires on the cap. I was saying to put them on the cap in the correct firing order but putting them on counterclockwise on the cap. Since the dist. turns CW then shouldn't I put the wires on the cap in a CW manner?

Tomguy · #6 03-21-2006, 12:48 PM

1:00 should be #1. Then go clockwise indeed with 5, 4, 8, 6, 3, 7, 2. #5 should be at 2:30, not 11:30. #4 at 4:00.

What do you mean "Cant get to 5° ATDC" - are you too advanced (0°, 5° BTDC) or too retarded (10° ATDC)? The car will start and run at 0° or 5° BTDC. It MIGHT at 10° ATDC, but not well.