There will inevitably come a time in your Z-Car ownership when you will need to replace your spark plugs. Some decide to replace their plugs fairly often, every 10,000 miles or so. This is fairly normal for a vintage car like the Z, but you can likely get away with waiting a bit longer than that if you wish.
Obviously, if you experience signs of spark plug failure, it is likely time to replace your plugs regardless. On a 240Z, 260Z, or a 280Z, your best bet is to purchase a set of NGK BP6ES spark plugs. Of course, you can find other (equivalent) plugs, but the BP6ES is the tried-and-true option for this car. If you wish to purchase online, you can buy these here. Although these come pre-gapped at 0.031in (0.8mm), you will want to make sure you double check the gaps with a spark plug gap gauge that can accommodate the gap range we are looking for, such as this one.
If you would prefer to watch a video of this guide, it is embedded below or you can watch directly on YouTube by clicking this link.
|Model||Spark Plug Gap (Range)|
Note that you may come across a few NGK plugs that have similar model numbers, such as the BPR6ES or the BP6ES-11. These are ultimately the same plug, but have slight differences. The BPR6ES merely means that it is a resistance plug which is used suppressing electrical interference caused by sparking. This can be helpful in cars that have on-board computer systems so in a vintage car like the 240Z, a resistor plug isn’t really necessary. In fact, resistor plugs actually cause a decrease in spark power, but it is so slight that it wouldn’t really make a noticeable difference. If you can only find NGK BPR6ES plugs they will work just fine. The BP6ES-11 is the same plug, just pre-gapped to 0.044in (1.1mm), but since you will be checking (and modifying) the plug gap, you can purchase those and they will work.
To remove, you will want to use a 21mm or 13/16in deep/sparkplug socket, such as this one. You may find that some plugs do not look all that worn or in need of replacement, but in general it is always a good idea to replace all 6 at once with brand new plugs. If you choose to use anti-seize, be careful not to apply too much. Lightly applying some grease to the threads should be enough though. Torque the plugs to 11-15 ft. lbs.