73 S spark plugs

[philip guiral]

I've got a 73 S that runs very well but the plugs foul-up if it doesn't start the first time. I've got Bosch platinum W3DPO. Should I be using something else?
Thanks

[denson]

Is your CDI operating properly as this should not be happening? If the CDI box is 100%, how rich are you running?

[RSTarga]

Switch to Nippondenso or NGK and check your mixture. Those new platinum plugs are not the same as the old 265 p21 that was originally on this car. I can't remember what the NGK equivalent is.

[RSTarga]

NGK Iridium BP8es should work well.

[boxster03]

the 3's are too cold. you should be using 5's or 6's.

[Flat Six, inc.]

Keep in mind NGK and Bosch are opposite as far as heat range goes....definitely run a hotter plug...

[Steve@Rennsport]

Switch to Nippondenso or NGK and check your mixture. Those new platinum plugs are not the same as the old 265 p21 that was originally on this car. I can't remember what the NGK equivalent is.

The DPO's are the same good plugs as the old P21's; only the designations are different.

Now,....3's are far too cold for street use in these cars due to the state of gasoline chemistries and I'd suggest a W5DPO or a 6 or 7 in an NGK.

[bliebler]

The DPO's are the same good plugs as the old P21's; only the designations are different.

Now,....3's are far too cold for street use in these cars due to the state of gasoline chemistries and I'd suggest a W5DPO or a 6 or 7 in an NGK.

In my 73S, I use NGK #7's for the street. It runs OK on the #8's, however, it starts and idles much better with 7's.

[ThomasTe]

A previous 2.4 S plug thread:

http://www.early911sregistry.org/for...ad.php?t=12643

[gled49]

Steve is right, same plug different number. I run W4CS. It is a heat rang hotter and has a silver tip. Stay away from the platinum wire plug Bosch makes, where you cant see the tip outside the porcelain.I perfer Bosch for there plugs plating over others. Gordon