This afternoon, I took my coils off so I could show some pictures of how my plugs look after installation....You can not get your head down far enough to manually look at the black index dots at the base of the plugs but I could get a camera at the correct angle to snap a few photos. That is probably why most people refer to the letter on top for orientation since the dot can not be seen at that angle just by looking... However, the letter does not always line up with the black dot....The black dot ALWAYS lines up with the electrode....
Here is a picture that shows the same spark plug taken from two different angles....I highlited the black dot location in a red circle:
Here is a pic showing I should be using A type spark plugs:
Finally, here is a combined picture of all three cylinders. The green line shows the horizontal horizon in each picture. The red arrow points to the black index dot on each plug. The yellow square points to the top of the letter "A" stamped on each plug....Notice how two out of three letters are close to alignment with the black dot and the other is way off....You can not rely on the stamped letter unless you individually compare each plug as taken out and the new one inserted while predicting where it will end up after torque:
As you can see, all three of my black dots are in the same location (within a few degrees). I reduced the size of the photos to about 25% of original but the hi-res photos clearly show the black dot location.
If you imagine the cylinder head turned up-side-down as in the photo Eli posted, you will discover my spark plugs line up with the other cylinder head...It also shows that replacement plugs will end up at nearly the same location when torque'd to spec with some anti-seize.
I think this and Eli's conformation proves 100% which way the electrode ground tab faces when installed.
When I look at the service book showing the location of the primary and secondary locations, it appears to me the opening is facing the secondary (vtec) valve which may make sense for performance reasons...
Looking at page 6-10 (VTEC rocker arm test) it points to the primary valve as letter A and the secondary as letter B....Also page 6-31 shows the cam lobes for each valve noting the direction of the timimg chain. Now you have imagine the head in Eli's picture turned around and up-side-down when referencing the book.
I think the open end mostly faces the VTEC intake but the primary intake is not obstructed by the ground tab either.
Hopefully this anwers this question about the ground tab position per Honda's specs.
JoeCVT = Just your average CVT owner
__________________
2004 CVT Red Insight (purchased May 2011)
Relocated outside temp sensor near mid engine
No other mods performed yet
2003 CVT Blue Insight
Modified version of MIMA_L (with foot pedal)
Automatic warm air intake (all season)
Low Speed Auto Stop (LSAS)
ABS - IMA regen enabler (allows regen during ABS)
Relocated outside temp sensor near mid engine
Cooling fans powered by 12V Solar Panel
2001 MT Blue Insight (purchased Nov 2011)
Not registered yet
Excellent, joe! Thanks for taking the time to illustrate it so well for us.
__________________
Insight #1 - Silver '01 5MT @ 158,388 as of 7/11 - Best Tank: 84.5MPG over 807mi
Insight #2 - Silver '01 5MT @ 450,000 as of 1/12 - Best Tank: 86.0MPG over 800mi
Insight #3 - Silver '00 5MT, MIMA #163P, BCM Gauge, OBDIIC&C Gauge, BetterBattery @ 228,869 as of 1/12 - Best Tank: 78.4mpg over 687mi
Do you know where the gap ended up after you installed them?
Sam
No but I didn't need to either. The whole point of buying the Honda plugs with the A B C D stamp to match the head is that once you tighten the plug, the gap ends up right where it's supposed to.
Quote:
Originally Posted by joecvt
That is probably why most people refer to the letter on top for orientation since the dot can not be seen at that angle just by looking... However, the letter does not always line up with the black dot....The black dot ALWAYS lines up with the electrode....
You can't refer to the letter on top for orientation. NGK probably just loads a batch of A plugs for example into an ink jet printer to print that letter on. They are in no way ment to match the position of the gap, it just identifies the plug. And as mentioned before, you don't need to know orientation if you have the matching plug for the head.
No but I didn't need to either. The whole point of buying the Honda plugs with the A B C D stamp to match the head is that once you tighten the plug, the gap ends up right where it's supposed to.
Right, but it would have given us another datapoint as to what direction Honda intended the gap to face. I think JoeCVT confirmed it. Thanks, Joe!
Even if I buy the Honda B plugs that my engine uses, I will double check that they point the right way. Our little engines need all the help they can get!
Thought I would revive this good thread, adding my own experience to the mix. I recently bought an Insight (2000 MT), pulled the plugs. It had some 'double platinum' autolites in it, pretty worn, and, as I came to discover, not quite 'clocked', or indexed, in the right position. Two of them clocked correctly, one of them didn't. I looked up new plugs at Majestic Honda - ~$19 each including shipping. Went to my local Honda dealer and they said they were $26 each, but maybe they could do $21. I thought I'd return to O'reilly autoparts, where one of the employees had told me she could order any NGKs for me...
Anyway, to make a long story short(er), I gave them the part number and explained the situation - with the indexing and such. They only had one choice. My head has the "B" stamp next to each plug hole, which seems to be the most common. They ordered these plugs for me, saying they'd work. When the plugs came in, the part number was different and the plugs had no letter stamp on the top and no dot on the collar, next to the insulator. But I decided to give them a try. And they work. They're iridium and probably exactly the same as the OEM - just without the indexing marks.
I marked where the electrode is, and when I snugged them down and checked, all 3 clocked in the same direction. The only other thing is that the gaps were bigger than spec, about 0.049 instead of 0.039-0.043. I've read that you're not supposed to re-gap iridium plugs, but I did, very carefully and only in one direction, making the gap smaller...
Here's some picts. The plugs are NGK LFR5AIX-11 (stock are ILZFR5A-11). Oh, the best part is, they're only $8.50 each. OK, no, the best part is, my car was running even better than it was, maybe about 4-7 mpg better, easier to prevent assist from kicking in, more power, smoother. And to me it felt good before the change...
Thought I would revive this good thread, adding my own experience to the mix. I recently bought an Insight (2000 MT), pulled the plugs. It had some 'double platinum' autolites in it, pretty worn, and, as I came to discover, not quite 'clocked', or indexed, in the right position. Two of them clocked correctly, one of them didn't. I looked up new plugs at Majestic Honda - ~$19 each including shipping. Went to my local Honda dealer and they said they were $26 each, but maybe they could do $21. I thought I'd return to O'reilly autoparts, where one of the employees had told me she could order any NGKs for me...
Anyway, to make a long story short(er), I gave them the part number and explained the situation - with the indexing and such. They only had one choice. My head has the "B" stamp next to each plug hole, which seems to be the most common. They ordered these plugs for me, saying they'd work. When the plugs came in, the part number was different and the plugs had no letter stamp on the top and no dot on the collar, next to the insulator. But I decided to give them a try. And they work. They're iridium and probably exactly the same as the OEM - just without the indexing marks.
I marked where the electrode is, and when I snugged them down and checked, all 3 clocked in the same direction. The only other thing is that the gaps were bigger than spec, about 0.049 instead of 0.039-0.043. I've read that you're not supposed to re-gap iridium plugs, but I did, very carefully and only in one direction, making the gap smaller...
Here's some picts. The plugs are NGK LFR5AIX-11 (stock are ILZFR5A-11). Oh, the best part is, they're only $8.50 each. OK, no, the best part is, my car was running even better than it was, maybe about 4-7 mpg better, easier to prevent assist from kicking in, more power, smoother. And to me it felt good before the change...
My experience; i ordered those plugs and installed them today in my b-indexed head; they don't line up the way you indicated in this post. they're off by 10-15 degrees.
__________________ 2002 Red Honda Insect 5MT
Detriments: 270,000 miles, P1447+P1449 IMA failure (bad battery), P1420 catalyst failure
Mollifying modifications: Scangauge, 70% condensor blockoff, OEM tires at (more than 50)psi, clutch bypass switch
Stats: 51 lifetime MPG when purchased late 2011; 52.1 lifetime MPG current.
My experience; i ordered those plugs and installed them today in my b-indexed head; they don't line up the way you indicated in this post. they're off by 10-15 degrees.
Maybe you have to finagle the torque a little - I didn't use a torque wrench, but by feel I didn't have to stress the plugs to get them to line up, i.e. the tightness felt about right. I never use torque wrenches on plugs, seems too sloppy to me, the wrenches have no feel and don't inspire any confidence... In any event, I hope you can get them to work...
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