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Replacing plugs, wires, and cap for 76 450slc

3K views 24 replies 8 participants last post by  RadioTek 
#1 ·
Hello,

I ready to replace my wires, plugs, and caps on my 450slc. I've done this for my s500 and didn't know if there was anything special I had to worry about for this car? I looked all over this forum and didn't see any instructions for this job.
If I've overlooked something I would appreciate if someone could point to the info. To be sure I will do one wire at a time. Maybe that's the only info. I need. Any info. would be greatly appreciated.

Thanks,
Troy
 
#2 ·
Engine COLD.

If you are not comfortable remembering where things go....use masking tape and a felt pen. The dist cap is keyed....so it will only go on one way.

You can mark your old one at each wire tower with the cylinder #.

I keep it simple for this exercise. #1, 2, 3, 4 RH starting from the front and #1, 2, 3, 4 LH starting from the front.

And you might want a torque wrench for tightening the plugs. Backyard mechanics have a penchant for thinking tighter is better....and that's not always the case.

You'll also want a feeler gauge set to gap the plus properly. Usually Bosch plugs come properly gapped (.032) but all you gotta do is drop one....
If I've over simplified this....I'm sorry....I don't know your skill set.



Good luck.
 
#15 ·
Changed wires and cap yesterday. Does anyone know the a local auto parts store and part # for the plugs I need? I checked Napa for the prt # 7832, but these are for
13/16 adapter. I was told I need 5/8 and not sure what the part # is.

Thanks
Troy
 
#19 ·
Lubricate the plug thread

I would prefer lubricate the plug threads with copper or aluminium paste. My wife audi service interval went over the service period and all the pulgs were nasty to open from aluminium head - all of them were corroded tightly into head threads.

I think the copper or aluminium paste will provide better corrosion protection and help with correct tightening torque.
 
#20 ·
update:

Added all new plugs except one (front right). It was a little hard to get to. I will probably have to remove something to get to it. I did notice that the plug wires
didn't have that same click when attaching to the new plugs. However, the car cranked just fine. The idle is a little uneven, but I will have to further investigate to see what the cause is. Also, the 13/16 socket that I purchased rubber insert does not grab the plugs like it should. It appears to be to large. This makes it tricky when removing and inserting the plugs in awkward locations. Maybe I just have a bad socket. It was only a $1.50 so maybe that's the reason?:)
 
#22 ·
Go ahead and remove the overflow tank. You don't need to disconnect the hoses to get it out of the way enough to get to the plug. Just 3 screws and sort of wiggle it in and up and you should be able to move it out of the way. There should be enough slack in thehoses to let you do this with little trouble.

Happy wrenching,
Scott
 
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