260 Z Spark Plugs

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I took my car to the local drag strip for test and tune night last night. This was the first run with NGK BPR7EIX plugs, one range colder. The car was missing like crazy. Just wouldn't run, sounded like a carb air floats was stuck. I pulled the air filter and checked the floats, they did fine, no issues. Finally gave up and put the car back on the trailer without making a pass. I pulled the plug wires one at a time and found that I was missing on 2, 3, and 4. So it is not carb related. Pulled the plugs and a friend who stopped by to help asked me when the last time I put new plugs in was, when I told him that they were brand new he was shocked by how dry black fouled they were. And yes, the 260 carbs run pig rich at idle, and it was about 80 degrees.

When I got home I put BPR6EIX plugs in before I even backed off the trailer. Purred like a kitten! I never would have thought one heat range would have made that big a difference. After detonating one engine and blowing a head gasket, probably by detonation, I am skidish, so I have gone to extremes here. The slug that blew the head gasket at Kershaw this summer turned out to have about 42-45 degrees of advance it in. That is probably enough to blow any motor, but I wanted to try the colder plugs as well.

Any ideas or magic you can pass along?

Mike

[kthomas]

I would just run BPR6ES in it. Old School Car + New School Plug = Bad Kharma.

Actually, some of the Sunbelt motors had platinum plugs in them, but we ran conventional 4 prongers from NGK.

[Parrish57]

For about the last year or so I've been running Bosch Platinum +4 plugs. Part no. 4417. I haven't experimented with other ranges of their plugs. When I ran the conventional NGKs the car would run like crazy for a few races but start to go off. The Bosch plugs seem to last a lot longer. As a matter of fact I can't recall having to replace them from lack of performance, I just do it out of habit.....

P.S. I would also advise AGAINST 45 degrees of timing!

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10-4 on the timing, everything I have seen seems to lead back to that being a bad plan. When I was explaining why I had the cold plugs in and told him about the timing issue, he said that I better be careful, that much timing could lead to a blown motor. I told him that in my experience it could lead to at least one, but that I am hoping to have learned enough to stop at one!!

Cave man say, "fire bad!"