For a Carb'ed V12 I'm thinking NGK BPR6ES gapped at 0.25mm but there seems to be a conflict in gap size and if a resistor plug should be used or not.

Ideally you'd want as much spark as possible so a non resistor plug makes sense, and a copper plug conducts best.

If you own a carb'ed V12 what are you running, whats the gap, and why did you choose it?

Thanks.

 

All my PreHE run NGK BP5EY gapped at 0.030".

Never varied that in Sir Arthur for 550000kms, so I reckon the car is as happy as me and a bottlke of JD.

 

Finally got around to replacing these plugs this weekend. I had my 9 year old son help me. He got to the 5th plug in the left bank and couldn't loosen it. I'm thinking its corroded or his reach is limiting his strength. Nope, it was cross threaded and fought me all the way out. Now of course, I cant get the new plug to find decent threads and will get to 2 full turns and essentially lock up. I'm hoping I can use a chase and clean up the threads before I go to a 14mm tap and make new threads. I really dont want to use a helicoil if I can help it.

 

Bugga.

Should be able to chase it with patience and time.

I dip the chaser, or the thread tap if it comes to that, in Wheel Bearing grease to contain any swarf that may happen.

 

LOL Grant!
Is there Any time using a tap that swarf doesn't happen??
Hopefully it only happens Outside the hole!
(';')

 

I agree, BUT the number of "qualified" types I have pulled up over the years doing that to spark plug threads with a dry tap.

They simply have NO idea.

One accused me of finally losing my marbles, mmmm, and claimed "the engine will blow the crap out the exhaust, no problems".

 

Maybe the swarf will be harmlessly blown out. Or maybe not.

I look at it this way:

There's no good reason NOT to grease up your thread chaser (or tap).

Cheers
DD

 

Swarf!!!!


1. Yup, why chance. A gob of grease can only help and hurt not one zip!!! The flip, on me!!!


2. A few decades ago, I mixed and matched two Toyota FJ40 six cylinder engines together to make one. Differing generations. Close, but different!! I needed to tap into an oil passage to plumb oil up into the Rocker arms. Not hard, I used the drill and tap process with grease to catch the swarf.


3. My son is a self taught and ultra talented machinist. But we disagree on chafe vs swarf nomenclature !! Oh, other stuff as well!!


Carl
nst.
tra gde

 

I used goopy bearing grease to capture any swarf of which there was an alarming amount actually. I did manage to get this plug in and another 2 that had the same problem. Previous owners/mechanics suck.

Anyway, the car starts and idles smoother, sounds better and throttle response is much crisper. A cap, rotor and set of leads should complete the ignition side tune up.