spark plugs - PeachParts Mercedes-Benz Forum

#1 01-12-2005, 07:12 PM

what is the very best spark plugs

for a 450--1979?? Thanks, Dennis

fahrgewehr2 · #2 01-12-2005, 07:57 PM

Whatever your owner's manual calls for.

#3 01-12-2005, 08:14 PM

I am not stupid i have all the factory manuals, owener manual,ect:i am sure there have been upgrades in spark plugs sense 1979??? Thanks,Dennis

fahrgewehr2 · #4 01-12-2005, 08:32 PM

There have been upgrades, but they do not work well in the older motors. Stick with the old copper plugs your manual calls for, do not get the new bosch platinum plugs that the store will try to sell you.

Didn't mean to imply you were an idiot. Issue has been discussed here fairly often, and everyone agrees that sticking with the OM's original recommendation is the only way to go.

#5 01-13-2005, 05:19 AM

My guess is that they probably used Bosch plugs. NGK jap plugs are rated very well too and are what I have in my 80 450sl but I have not had this car very long, or running properly yet to recommend what plug seems to work best in these engines, but would agree too to stick with the older technology plugs.

BB

ncgirl05 · #6 01-13-2005, 05:49 AM

That would be the best move - I installed platinum plugs in my 77 450sl and my mechanic, upon hearing what I'd done, told me to only use the copper spark plugs. He said he'd had many folks come in with problems that were related to using the wrong type of spark plugs.

LA

#7 01-13-2005, 07:49 AM

Thanks for a the info.on the spark plugs to use the older engines, i guess i just asumed their must be a more advanced plug in 26 years, must put it in the right prospective--Thanks, Dennis

autozen · #8 01-13-2005, 10:40 AM

As a 30 year veteran MB mechanic, give me NGK everytime. You can't buy a better plug. Yes, stick with the type of plug your car calls for. IIRC it is either BP5ES or BP6ES. Do not use platinum and do not use resistor plugs. Your ignition has the resistors built in. There is 5000 ohms built into the rotor and either 5000 or 1000 ohms built into the plug connectors.

Back when plugs needed to be changed every 12,000 miles mostly due to leaded fuel, the plug mfgs just about gave the plugs to the auto mfgs in hopes that the new car buyer would tend to stick with has worked so far. With todays new cars going 100k before the plugs need replacing that segment of the market has disappeared so the plug mfgs have become competitive by designing new style weird looking plugs that you the consumer just has to have. At least that what the ads lead you to believe. You don't need these new style over priced plugs in older vehicles and in many cases they don't perform as well as the originals.

As an aside if I had one of those 100k plug vehicles, I wouldn't wait for 100k on the clock. I'd have them changed at 50k. The plugs will last 100k, but by that time they are pretty well welded into the heads. They can be pretty nasty to get out, and if a head or engine needs to be pulled to remove a broken or seized plug, guess who gets to pay the labor. I don't think warrantees stretch that far.

Peter

#9 01-13-2005, 11:11 AM

Hello Peter,i just orderd ngk plugs, thanks, ineed a dist. cap also ,they list two, only one # at the diffarent at the end, will they both fit--67 or 68 ??? Dennis

autozen · #10 01-13-2005, 11:29 AM

Either cap will fit the dist, but only one will match the plug wire set. You will need to supply the engine # which is located on the back of the block below the left head. you can see it by looking down at the back of the left head. You may need to spray carb cleaner on the #s. The # should be 14 digits long. You only need the last 6 digits.

Peter

#11 01-13-2005, 11:34 AM

Thanks Peter, i will take a look---Dennis