280sl on 5 cylinders / spark plugs?

[cjerem51]

Hello,

I'm a french guy and sorry for my english! 

My father just bought a 280sl and it's runs well.
But after 15Km, at 90Km/h, the engine started making a different noise, like the engine runs on 5 cylinders

After verification we have ignition on all the cylinders but after removing the spark plugs we can see a problem on the spark plug of the first cylinders.
In effet,we have a lot of black deposit on the spark plug.

I think we need to change plugs at first
What do you think?

The spark plugs on the 280 are bosh super W5DC, but I saw that many of you have spark plugs of another type.
Can you enlighten me on that?

Thank you!

[ja17]

Hello,

Check the resistance in the spark plug wire going to that cylinder first. You may have a bad resistor end,or a bad plug wire and no spark is reaching the spark plug. Change the spark plug of coarse.  You may also wish to do a compression check on that cylinder at this time.  A lot of us use the NGK BP6ES or BP5ES spark plugs which have nor resistance. Bosch no longer makes "non-resistor" spark plugs which are correct for these ignitions.

[cjerem51]

Thank you!

BP6ES are better than BP5ES? 
BP5ES are too hot? No?

[philmas]

Hi! nice to welcome another french guy on this forum!

W5DC are NLA. I use NGK BP6ES and have been pleased with them ever since.Not sure BP5ES will make any difference, just somewhat hotter, better if you drive often in slow traffic maybe...