OK…moving along on the engine refresh. What is the recommendation for modern spark plugs ?
My XKE is a 4.2L, 1965 OTS.
Thoughts / experience appreciated ! ( most recently used NGK BPR5EGP 7082 )
Thanks,
Harold
NGK has been my favored plug for 30 years.
The Champions specified in the owners manual have worked well for me though I have also used NGK BP5ET with the triple electrode and they were fine too.
Old thinking by the small block Chevy guys and Ford “Shop Tips” was interesting and I’m a complete believer. You want the longest protrusion into the combustion chamber consistent with clearance issues. You must keep in mind that a long snout can mean a hot plug - not usually a good thing for pre ignition. On Chevies a “44” (if I recall after some 43 years) had a real short nose.
Reason for this? A longer plug allows more effective advance and a more central electrode position. More effective advance without adverse effects due to the benefit just being positional.
With our cars with the large combustion chamber getting the flame started with the shortest average distance to the perimeters (maybe ‘root mean distance’ may be the term) seems desirable. I also clocked the electrodes even though most experts say it doesn’t matter. On our combustion chambers I think it does matter due to the plug going in straight rather than radially.
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On a low-compression street-use engine (less than 11:1) it doesn’t.
On my Datsun racer (13.5:1) I had to clock the plugs because at TDC, w/o clocking them, the ground electrode would hit the crown. I was running ~0.040" v-p clearances.
Back in the mis-80s, Champions–a plug my Dad had used his whole career–begain failing, by exhibiting high-pressure misfires… like 2-4/box of ten.
I switched to NGKs.
Tried some Champs, again, in Tweety, when I rebuilt him… same thing.
Back to NGK.
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Clocking wasn’t to clear pistons, but the theory was electrode exposure and spark shrouding from the ground. While that seems far fetched to me, if you look how our electrodes sit in the chamber, It seemed to me that in certain positions they don’t look “right”. Imagination - maybe, but I liked the way they looked when I put them in the way I wanted.
Thanks for being honest…
On numerous tests–done by Chevron, IMS–electrode position does not make a measurable difference in any performance parameter, of a low-compression/naturally-aspirated engine.
If it did, you’d see procedures and plugs for it.
Next time I replace my NGKs I’m going to a “6” heat range. Should be around 2024.
Lean is mean.
LOL!!! Riiiiight at the point the piston becomes a melted knob of reciprocating garbage.
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1/8 turn richer. That’ll bust your crank, Wiggie
,
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Wiggs what was your Datsun ?
Why run resistor plugs when you have resistor plug caps. Does it matter or not.
Good question ! I was not aware of “resistor plug caps” ? Am I just way behind the times ? I’ve been using resistor plugs for years…and intend to stay with NGK, based on a lot of feedback from my Jag friends…
Which one?
My first was a PL311: the family had the following.
-1971 PL521 (pickup)
-a series of roadsters, including a rare Japanese-spec (RHD) 1500, then a 1600, and then the not-so-great 2000.
-Mom had a kink for 240Zs, so she had 2 (after wiping one out in an accident).
-a BUNCH of 1200s, which were my personal favorites.
I began autocrossing my '71, slowly modifying it, till it actually got a little unpleasant to drive on the street. That’s the one that got backdated to a more stock configuration, and donated the go-fast goodies to a '72, which led to my first track car.
Here it is, in its Improved Touring trim (kind of like a hotted-up Showroom Stock class)…
…which eventually led to a fully track-prepped GT5 SCCA racer, built on another chassis. That track car had a wild engine in it, that I dynoed at an uncorrected 151 flywheel horsepower.
I like Datsuns…
If you have the champion plug caps they have a resistor built in
Just installed new champion caps and went to a ngk non resistor plug
I would think that too much resistance can not be a good thing.
Me too two of four Ive had / restored.
Still have the 67 red one.
sorry to hijack thread , now back to our spark plug programming
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OK, this one clearly falls into the overthinking category, but I’m still in that stage (to reference the seat belt discussion) where I care more about the damage to the car than my spine!
Mechanic recommended Champion EM 12YC spark plugs and after two days of searching, the closest I could find was RC 12YC which is a racing plug. Now, my inner 16 year old thinks, “Racing plugs, cool!” but while I’m dumb enough to watch a video or read a manual to try and do some things myself, I really don’t know much and am just curious if I wrote the wrong number down or I should stop worrying and just follow everyone elses lead and use the more commonly available plugs? For whatever reason, this guy is not a fan of the NGK’s so I’d prefer to stick with Champion.
NGK……Champions are now built in a sweat shop in Mexico
Terrible quality and reliability
Your can do what you like but I’d say the guys on this thread have a combined billion miles in an Etype
Most if not all go NGK
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Champions have a narrower heat range per plug…if you know exactly how you drive and you drive that way all the time fine…but a wider range in the NGK usually is better. Use a race plug if you drive wide open throttle from your garage to wherever and back. That would mean your garage is at the track. (A race plug is waaaay too cold)
Nick
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