A machine shop can permanently fix the head. Buying a used or even new one doesn't permanently solve the problem. Permanent solution is to have all 4 threads replaced with steel inserts at a machine shop.

We did that with my friends GE probably 80k miles ago and it's still running great. He had a valve job and new guides done at the same time.

 

Here's my speculations on the root cause...

1. Life doesn't start well since they are short thread plugs into an aluminum head. ALL other vehicles I've owned with aluminum heads use long thread style plugs. Even aftermarket aluminum heads from the '80's for domestic cars used long thread plugs.
2. Most cars that eject the plugs have also not had proper valve adjustments. I suspect that the too tight exhaust valves (since they tighten over time) cause a heat, pressure, or heat and pressure issue.
3. It's usually cylinder 3 that ejects. Maybe due to the PCV system or harmonics at that area of the motor? Not sure.

Overall, I'm betting that no Fit has ejected a spark plug that has had valve adjustments done every 60k. My friends ejected his at around 120k miles. Never had ANY form of maintenance other than sporadic oil changes.

That being said, ours has not ejected, but #3 is loose on every 50k plug change.

 

What I see on the wrecking yards are the leaking plugs on GD3 (plug is tight but gases are blowing past the gaskets (no I'am NOT talking about "corona" deposit on the plug above the crimp). The entire coil boot has heavy rust/tobacco colored deposit (typically seen on pistons of low compression properly tuned engines)

 

That's what our #3 coil boot looked like. Eventually failed and have replaced that one coil. All others are original and going strong.

 

its a shame someone cant send out some kind of letter to all GE8 owners. You know, informing them of this mistake in assembly. But maybe thats not correct. It could be that they simply expect maintenance to be done in intervals as mentioned above, but just dont emphasize the severe consequences of failing to perform them. consequences unique to our microvan.

I also have a theory on the two center plugs loosening sooner. Temp fluctuations. just a thought that doesnt benefit anyone, but the sides of the engines may cool a little quicker, and start to cool sooner. Cast aluminum (thats what our heads are, right?) I'm told by welders is a nasty metal and very difficult to work with due to composition and density variation.
it took me some doing to find a machinist who would repair a cracked cast aluminum intake manifold for me some years back. but there are those.
I was charged a hundred bucks to weld the one crack. not sure how much another guy might charge. and that was with me removing and delivering the part.

a new head will set you back far more.. I would recommend it, but if the pockets aint deep they just aint. either way the cylinder head has to come off to do a good job. should someone tell you otherwise, do consider: exactly how deep should the sleeve go in? can they accurately get the exact measurement and drill to it? if so, and they can show you, then go for it (and PM me to tell me how )
But.. if this is a situation where you decide its time for the car to go, have it helicoiled and start shopping for a new ride. sometimes janky fixes can sometimes surprise you and last quite a while.

I'm sorry this had to happen to you.

 

This is awesome data @doctor J .

On normal cars, spark plug changes are easy so it is reasonable to assume some OEM spark plugs loosened, colored coil boots tobacco, but plugs were replaced before major damage. In the wrecking yards, that would show tobacco colored deposits on the coil boots and tight spark plugs.

On the Fit, spark plug changes are uber-expensive and too difficult for average DIY guy to bother with. So I suspect most Fits are on OEM spark plugs. Yet, spark plugs are tight and coil boots are colred tobacco.

---> Not sure what would cause this. Maybe it is possible some OEM plugs actually have loosened but the carbon deposits, oxidation, and dissimilar metals issues conspire to require significant torque to remove a spark plug?

 

Umm...spark plug change on the GD Fit takes about 15 minutes. It's literally easier than changing the oil.

GE Fits are only more time consuming because removal of the cowl is necessary if you want easy access. still a very easy job. Just takes more time.

I've owned countless cars and I can tell you that most OHC 4-cylinder, front wheel drive cars are pretty darn easy. Transverse mount v6's and v8's are generally the hardest. Add turbocharger plumbing and they usually get even more obstructed.

 

It's easy on our 4-plug vtec engines, more difficult on the 8-plug iDSI engines!

 

Well, an hour ago someone brought me 2002 Accord (4 cylinder) for ignition components check, and I've found that all plugs were only finger tight (it had genuine 105,000 mile type of the plugs)On the blurry photo attached, you still can see a virgin crush washer (arrow)

It was finger tightened for hell knows how long but did not blew up!

So I've tighten them up. The wire boots were not damaged either! Same thing I've saw on my 1987 camry during the purchase inspection!

 

It is possible to see if we can get a class action lawsuit against Honda for this. Just need enough people to be behind it. Today, I submitted information to have this looked in too. I will post up more information as I get it and if needed a link to where everyone can submit their info for the same issue.

 

It's crazy to me that the manual says its okay to use 87 octane or higher on these cars. After reviewing the L15A7 engine and realizing that it's base compression ratios are 10.2:1 - 13.5:1 is insane to recommend a base of 87 octane for this car. I wouldn't use anything less than the highest octane available for your area. 93 or 91 at the minimum.

I can see why the potential for spark plugs to blow out like that..

 

Count me in. I just started a thread on my spark plug issue. For want of a better-holding plug I now need a refurb'd engine (if I even do it).

 

Were these the original plugs, and have they ever been removed since the car left the factory?

Just wondering if plug blowouts might be related to a service issue.

Thanks.

 

They were the original plugs, replaced @ 77K miles four mos ago (I thought, could be wrong, the recommendation was... 90k miles?). Service issue as in me not getting enough service? If that's what you're asking (and it's a fair question!!) … well I did all maintenance as minders popped up, oil changes. I didn't treat the thing with kid gloves as it was a daily driver not an heirloom. I must be old school or worked too much with lawn mower engines... never thought spark plugs could be such a big deal.

 

Aluminum welding isn't that special - just different. Last week I had a local welder repair a thin aluminum die casting that I broke while trying to force out a rusted steel bolt. I've seen prettier welds, but he laid down 2 inches of bead on each side of the casting (I pre-cleaned it with a SS wire brush) and I was out of there 20 minutes later and $20 lighter. This guy is dynamite on aluminum handrails and custom spiral staircases, but I wouldn't bring him a head to repair.

A good automotive machine shop can be hard to find in some localities. Some are great at machine work, but so-so at welding. Automotive head shops tend to be few and far between because there isn't always sufficient demand for this specialty. If your head is cracked or the Heli-Coil blows out, then you can have the spark plug hole welded closed enough to be rethreaded. That's where welding excellence is needed. Heat must be controlled so as not to stress the head and possibly encourage warping.

That said, Heli-Coils (and similar inserts) aren't that difficult to install, and they're all quite strong as long as the Heli-Coil hole is not over-bored. The main thing is that the head should be removed in order to insure a proper job. People who install Heli-Coils with the head on the engine run the risk of metal particles (from drilling and tapping) entering the combustion chamber and damaging a ring, valve or other component.

Some people recommend adding Loctite, but Heli-Coil doesn't recommend it and Loctite Red 271 is only rated for 300 degrees anyway. Besides, what happens if some residual Loctite gets on the spark plug? You run the risk of damaging the threads next time you remove the plug.

 

Pretty nice for 140,000 miles.
Here's a picture of the OEM plugs on my 2009 Sport after 140,000 miles. The threads seem long enough. Do the new Fits have shorter threads?

 

I don’t really buy the short thread argument either; but it is true with fewer threads there is less space between “too loose to retain” and “crushed the aluminum threads “. To answer your question — long thread plugs look amusingly long. I’ve never had a car with those.

 

Thanks for the reply, Tripp.

What I meant was this: Did your blowout occur on an engine that had no service on the plugs since the factory installed them? It sounds like the answer, in your case, would be "No." So, is it possible that your blowout occurred because someone incorrectly installed new plugs? (I am referring to a problem with the installation of the plugs, not the plugs themselves.)

Hope that is clear.

 

The original factory plugs got replaced when cyl #3 went bad (needed helicoil or time-sort) @77k miles. 4 mos / 3k mi later #3 went bad again. So could it have been a bad fix or just chalk it up to “no guarantees” as stipulated at time of repair.

 

Same here.
Blew out #3 plug yesterday.
67k mi on engine.
2008 Fit
Had never changed or checked spark plugs since new.

Oh! The joys of installing an insert on a Sunday!