w108 ignition parts

[alee8677]

Hello everyone. I am the proud owner of a 1973 280se 4.5. I just bought the car about 3 weeks ago and I've been slowly trying to clean her up. But to get to the point, I had a question for you about the ignition. At the moment, I purchased 8 Bosch WR-7-DC+ along with the Karlyn-STI spark plug wires last week from the fine people here at PeachParts. So my questions are:

1. Does anyone know if these plugs are pre-gapped? And even if they are, does anyone happen to know what the gap should be for these vehicles?

2. The wires I bought state that they are for "Distributor Caps without Stud Connectors". What does that even mean? Does this have anything to do with the Spark Plug Connectors that they sell on the site? I intend to replace the cap and rotor as well, so if I were to purchase the caps that say "with Push On type connectors"...would I need to buy these connectors?

My apologies in advance if my questions seem "noob-ey", but I have searched this forum as well as a few others and I can't seem to come up with a clear answer. I would consult the MB manuals that I just purchased, but they were stolen out of my car from the guys at a local dealership

Thanks for reading everyone!

[hookedon210s]

1. IIRC the proper gap is .028" to .032". The end panel of the plug box will state what the plugs have been gapped to. I just checked a box of those plugs on Amazon and they are pre-gapped to .036" so those would need to be closed a bit. Plug gappers for your purpose are sold at the counter of most McParts stores.

2. The early 4.5 liter distributor cap has wire connectors like any other older vehicle you are familiar with. When MB changed to breakerless distributors the distributor caps were increased in size due to increased secondary ignition voltage and the caps featured aluminum/brass/copper machine screws embedded in the distributor cap for the ignition wires to connect to which one would assume is for better conductivity or wire retention in the cap. When MB changed to super duper EZL ignition round about 1986 on its V8 engines the distributor cap was even further enlarged to prevent upwards of 50K volts from arcing in the cap. See the pics below.

And yes, the wires that are used must be matched to the style of distributor cap that is used. The wires and cap that you bought on this site should work together just fine.

Good luck with your 4.5---I have owned several and they are great cars when maintained properly. Mark

[alee8677]

~Applause~

Thank you, Mark! Your response was incredibly helpful and the pictures cleared my questions right up.

I love walking out and seeing my car parked out front. Now I just need to get 'er running like an MB should!