A quick spark plug question please....
 

I am currently rebuilding my 1984 3.2 L engine due to a broken #6 intake rocker arm. The spark plugs that were in the engine for the last 10 years or so are the bosch super w6dc. They worked very well and look fine.

I have made changes to the engine ...I replaced the USA Pistons with the Eurostyle ... and I have replaced the stock camshafts with the WebCam 20/21 profile timed at 2.05 mm at TDC overlap.... I have a stock ignition system. My compression ratio is now supposedly 10.3. Up from the 9.5 compression ratio previously


I have noticed that the Bosch W6 DC spark plugs are not readily available. Some British eBay sites have them but not our host pelican parts.

I really don't have much experience with various spark plugs....I want to stay with the Bosch brand And copper....what spark plug would you use in my situation considering I upgraded the compression ratio?

thank you

Perhaps a moderator can point me in the right direction?

Just Google "Bosch w6dc spark plug equivalent" (but spell it correctly). I saw several options that I'm sure are available at the local auto parts store. I use NGK myself. The closest would be wr6dc from Bosch. They are same except they have a resistor for EMI suppression. They will work fine.

-Andy

Thank you for responding!

I guess the next question Would be....do I want equivalent plugs to what I was running before?

Since I have raised the compression ratio...I was under the impression I need a colder plug....is this accurate....?

Basically I'd like to know what Bosch plugs people are running here with the euro spec 3.2 liters....

I use NGK BPR8ES spark plugs. They are copper resistor plugs and are 2 steps colder than the Bosch W6DC. If you want Bosch, you could use W5DC or W4DC. I have a euro 3.0 engine in a race car.

I would use the colder plugs with your new engine. If they are too cold they will "carbon up" after a few thousand miles. If they do you can go back to the hotter plugs.

-Andy