I have a 240Z with L28.  It has a  240Z distributor with electronic points and SU Carbs,

Do I install and gap plugs based on the 240Z ignition/fuel OR 280Z combustion?

I got the information below from zcarguide.com

ModelSpark Plug Gap (Range)

240Z 0.8mm-0.9mm, 0.031-0.035in

260Z 0.8mm-0.9mm, 0.031-0.035in

280Z 1.0mm-1.1mm, 0.039-0.043in

Edited February 23, 20223 yr by HappyZ

The Ignitor II is an adaptive dwell system, AKA current-limiting.  If you use it with the low resistance coil they suggested, the FlameThrower II (primary resistance 0.6 ohms), you should be able to use the larger plug gap.

In your opinion, should I buy plugs for a '78 280Z or a '71 240Z?  And then gap I'll gap them at 1.0mm -1.1 mm

I'd get the plugs for the engine - a 78 280Z.

Thanks, I'll give them a ride.  You have been very helpful.

Eh.. are they not the same BPR6ES from NGK? Overhere they are the same in my 240z '71 and 280zx '79..  theire gap is also 1,1 mm. (could be to big for the 240z ignition but it runs perfect on it..)

I think BPR6ES are gapped at 0.8 and BPR6ES-11 are the same, but gapped at 1.1. Either can be re-gapped to something else. 

1978 had the first "adaptive dwell" system for the Z's, I think.  At least they trusted it enough to run enough current to open the plug gaps.  The 1978 spec should work for the Ignitor II.

Some people like to run the projected tip plugs but I'm not sure it makes a difference.  Not sure why Nissan changed, maybe due to detonation issues with the leaner EFI systems.  Just a guess.

Thanks for the information.  I'm really close to everything coming together, so should be able to report back by this weekend.

 

I run a ps20 fireball coil with the e12-80 distributor on my my 240. I split the the low and high and gapped at .041 with the ngk bp6es. Runs great.