I only got 4 in my fit... I want my other 4!!!!

 

I always just tighten the fittings until they strip the threads...then back off half a turn.



J/K




or

 

Perhaps it's the wannabe spark plug nerd in me, but I find this thread fascinating, and I am grateful for the exchange of ideas, arguments and positions.

Question: The issue seems to be around achieving the precise and accurate torque on the spark plug as we install it. But what about the issue of avoiding a seized plug? Has this been covered in the discussion and I missed it?

Note 1: I've never heard of a plug blowing out of a head, like the OP describes. I suppose it could happen, but the close calls that I am aware of discovered that a plug was loose before a blow out occurred.

Note 2: I've been using anti-seize on spark plug threads and hand torquing spark plugs for approx. 30 years. No probems so far.

Note 3: I once drove up to ARP (arp-bolts.com) to by a bolt for a foot peg on a motorcycle (nerdy of me, I know), and they said to lube everything, all the time, always.

 

Marrk,

I find this stuff interesting too. I do this kind of stuff work. I'm kind of a geek. Some details like electronics and software bore the crap out of me. But hardware and mechanical design are interesting.

Avoiding a seized plug: Zinc or nickel plated steel plugs, cleaned, will not seize inside an aluminum cyl head. Use anti-seize if the torque spec is designed for it. Do not use anti-seize if the torque spec states dry, or doesn't mention anti-seize. In my write up in this thread earlier I mention 2 different published torque specs for the Fit plugs, one by the manual, and one by NGK. They're both different and correct (one with anti-sezie, one without). A lot of people have successfully used anti-seize in all their applications, regardless if the torque spec is for dry or we, for decades without problem, and they will swear by it, and they may never have any problem. To me, that's risky, that's all. As I've also stated before, there's probably enough design margin in many torque specs to account for oiled or dry, but spark plugs, I believe, are unique and should be treated with more understanding.

Your note 1: I've never heard of plug blow out either. I'm curious as to the root cause. I can imagine a loose plug blowing out maybe the last thread or two but I can't understand entire thread blow out.

Your note 2: You will likely never have a problem. Just understand the torque specs designed for dry vs oiled. (anti-seize is in an oil emulsion)

Your note 3: A lot of people swear by oiled or anti-seize fasteners and that's fine, but it doesn't diminish or negate the discussion we're having on this thread.

 

On another forum I belong to (Dodge minivans ) owners report finding loose sparkplugs after seeing misfires. This, on factory-installed plugs.

Those cars do not have coil-over-plug though. Why wouldn't the Acura (V6), Accord or CR-V (both K24 engines) owners report loose plug problems? (<--- all C-O-P designs)


For that matter, why wouldn't a bolted-on coil pack prevent a plug from coming loose?

 

I, too, have heard of this sort of thing (and it is what I was indirectly referring to above). It happened, not on Dodges, but on Hondas. I think Honda even issued a TSB on it. This was several years ago.

 

What year model Fit do you have?

 

I do not think this has anything to do with coil on plug design. It probably has to more to do with poor assembly practices. It would only take one lazy or hung over worker assembling engines to cause a lot of future failures.

 

Here is something I've gotten from driving and maintaining Japanese Cars & Trucks for the past 35 years. My dad bought our family's first Honda in 1978, an Accord Hatchback, then in 1980, a redesigned Civic Wagon. Then in 1982, he bought a new Toyota Pickup. All of these have aluminum engines. For the most part, my late dad and I kept the vehicles running for all these years. We learned to stay with either NGK or Nippondenso (ND) plugs and wires with the Japanese vehicles, when my sister one day had a mechanic service her Accord. The mechanic replaced the plugs with AC Delco plugs, and the car ran poorly. At the time, it was only about 5 Years old and a fairly low mileage car. Years later, my brother had the wagon serviced, and another mechanic installed Bosch plugs. Again, the car ran worse than with NGK and ND plugs. My dad's Toyota pickup always had either NGK or ND plugs, and never had serious issues with them. Dad and I made sure to stick with these 2 Brands whenever we would change the plugs. My sister learned quickly from the time she had the Accord serviced, and has never used any other plug on her Nissan Pathfinder she bought new in 1989. My brother also got reminded when he ended up with Bosch plugs and a not so powerful performance in the wagon. My brother, sister, our late dad and I have 6 Japanese Vehicles total...btw, my brother inherited the Wagon after our dad died. His other car is a 1995 Civic he bought new. My Fit is the 4th Honda we have among us. The key to keeping plug blowouts or failure is to check the plugs when your car feels like it's lost some pep. If your car feels a bit less powerful than when it was new, and you lost some gas mileage, it wouldn't hurt to see how the plugs are doing. I have used anti-seize on the plugs with no problem...a light coating is the key...don't overdo it. For those who had the blowouts, did your car start showing signs of less power some months before it blew out? My brother had a plug fail on his 95 Civic, where its electrode disintigrated in the cylinder. Prior to its failure, his car had a slight loss of power several weeks before it failed. I will check my plugs when my Fit comes close to 60,000 miles, or sooner if my acceleration starts getting slightly slow. I hope this helps!

 

I think it's a dealer mechanic who may have goofed. The Fit is made and assembled in Japan. Now it could also be a malfunctioning robot as well.

 

Here's a theory on plug blow out. If you torque an oiled plug or anti-seized plug to a dry spec, thereby potentially overtorquing by 50ish percent, you could have weakened or stripped the aluminum threads in the head.

 

I guess the real question is did the plug loosen up (come unscrewed) or did the threads is the head give way as you suggested. It is probably the second situation.

 

Same number as now. Unless you can show the provider was at fault, its yours.

 

That is the point. Unless the manufacturer or part supplier states that the threads are torqued dry, its by specification lightly lubricated threads.
Its always better to specify lightly lubricated because the range is tighter and thus better. As the range widens its more likely to be under or over torqued. And easier to 'de-bolt'.

 

I think I referenced an issue (see above) of loose spark plugs on Hondas. It was on S2000s. At the time, the cause was attributed to factory and assembly line error. They under-torqued the plugs. There might have been a TSB on it, but I cannot recall anymore.

 

2008

..................

 

The reason I started using anti-seize on spark plugs was due to having the threads coming out of air cooled VW heads when doing spark plug changes... I have continued to use the stuff more out of habit than any other reason. The new Iridium plugs made by NGK and Denso are unlikely to need to be prepped with anti-seize because they have a plated finish on the the thread surface... I'll continue to do like I have for over 40 years because - (1) It makes installation easier. (2) It makes the plugs easier to remove. (3) It has become a ritual I enjoy doing (4) It is easier to tell when the sealing surface of the plug makes contact with the head. (5) Who in the hell uses a torque wrench when changing plugs anyway?

 

I do.

 

Gosh! And I thought I was anal retentive for using anti-seize

 

Had you used a torque wrench, maybe you wouldn't have screwed up your VW head.