This is topic Never seen a spark plug like this... in forum Hunting Vehicles at The New Huntmastersbbs!.
To visit this topic, use this URL:
https://www.huntmastersbbs.com/cgi-bin/cgi-ubb/ultimatebb.cgi?ubb=get_topic;f=8;t=000061
Posted by DAA (Member # 11) on February 18, 2019, 08:07 AM:
My old Land Cruiser, which my 16 year old daughter has been driving since August.
She was on the freeway, check engine light started flashing. From her description the motor was misfiring like a sonofabtich and then it just died. She coasted to the shoulder and called me. It would not even try to crank. Just nothing. We towed it home and I pulled the codes and started poking around under the hood a couple days later.
Found this.
That's the coil pack from #6 next to the one from #4. Something looks off about that one from #6...
But the spark plug from #6 was the real doozy. Never seen one come out looking quite like this before.
Threads were mostly melted out of the aluminum head, too, of course. Piston and cylinder walls looked perfect though. So, just cut in a new thread insert with the head in place. New spark plug, new coil pack and new connector and wire pigtail for it. And, I'll be go to hell if it didn't fire right up and purr like a kitten.
She's been driving it on the repair for over a week now. So I think I'm out of the woods on the repair. Feel lucky it was so easy to fix. Was really afraid something much more expensive was going to be fried further upstream from the coil pack connector.
I'll take all the breaks I can get on this stuff.
- DAA
Posted by Leonard (Member # 2) on February 18, 2019, 08:20 AM:
Good luck but I can't see how you would be out of the woods? You don't think it's the result of a bad spark plug, do you? Wild ass guess/voltage regulator.
Good hunting. El Bee
Posted by DAA (Member # 11) on February 18, 2019, 09:48 AM:
I'll just have to wait and see if I'm really out of the woods yet. But I think I am.
Don't think the voltage regulator could have been involved. Can't think of a way it could be, anyway.
Obvious direct short. Only way to cause that much heat. Coil pack or plug first, I don't know, chicken or the egg I guess.
But I think just replacing all the shit I could see that was melted is probably going to be good for the duration. I hope...
- DAA
Posted by Leonard (Member # 2) on February 18, 2019, 11:16 AM:
Second guess. There's a limit, right? An act of God; Lightning strike.
Good hunting. El Bee
Posted by knockemdown (Member # 3588) on February 20, 2019, 06:34 AM:
Insulation compromised on wire, somewhere/ somehow? Could be anything, maybe rodent chewing? Dry rot form prolonged manifold heat? Just plain ol chafing?
Or, coil housing comped & allowed moisture inside?
Would like to read more on how ya tapped the plug threads, in place! How'd ya keep debris from getting down inside?
Posted by DAA (Member # 11) on February 20, 2019, 12:55 PM:
Fred, keeping debris out of the combustion chamber was pretty straightforward.
I used this tool to cut the threads and install the insert: Lisle spark plug thread repair kit.
It's your basic "helicoil" type repair. Cutting oversized new threads for a new thread insert. But I used a Time-sert shell, which I think is a lot better than the old helicoil style.
The time honored method for keeping debris out is simply to pack the flutes of the drill/tap with grease. But not fully packed. I just packed the lower portion at first. And only the flutes. Only where the cutting would be taking place.
Made a few turns. Backed it out, cleaned it thoroughly, packed the flutes with fresh grease again. Repeated. About six times. Packing the flutes as high as the cutting action each time. Only cutting a small amount before backing it out and cleaning all the shavings off, repacking with grease and repeating.
Rags wrapped around socket extensions, soaked in brake cleaner, lots of them, to clean all the grease out.
Shop vac with skinny extension.
150 PSI compressed air directly through new hole.
Inspect with digital inspection camera (bore scope). Verify absolutely no debris visible. I just have a cheap ass Harbor Fright camera. This one - Digitial Inspection Camera. Gives a surprisingly very clear view of the piston and combustion chamber though. To get an even better view of the thread area and cylinder walls I used my Lyman bore scope ![[Big Grin]](biggrin.gif)
.
Red loctite (Timesert brand) on outside threads of insert. Install. Let sit overnight (it was below freezing). Swage.
Nickel antisieze on threads of new plug. Install.
About all there is to it. Really, pretty dang easy. Had more trouble soldering on the new coil connector pigtail than I did installing the thread insert in the head. And honestly, I expect that thread repair to last the life of the engine.
- DAA
Posted by Leonard (Member # 2) on February 21, 2019, 10:37 AM:
I look for gouges from gripping that spark plug and don't see any? Was it just hand tight and a deep socket slipped on easily? I still can't imagine how it got in that condition? Did it happen over ten miles of driving or 3 months, or a sudden eruption? I have never seen a spark plug in anything close to that condition. LB
Posted by DAA (Member # 11) on February 21, 2019, 03:35 PM:
Leonard, the plug was just laying in the hole. If there hadn't been what was left of the coil pack bolted on plugging the top I'm sure compression would have just blown it out completely. I fished it out with vacuum hose.
I wasn't driving, don't know how long things took to get to that state. But I'm guessing once it shorted and started to melt it was all over pretty fast. Seconds, maybe.
- DAA
Posted by Lone Howl (Member # 29) on February 21, 2019, 04:20 PM:
Wow! Thats crazy.
Mark
Posted by knockemdown (Member # 3588) on February 22, 2019, 06:10 AM:
Thanks for the explain, Dave!
Interesting fix to a weird situation...something to learn from, for sure!
Posted by Leonard (Member # 2) on February 22, 2019, 07:25 AM:
Oh, so you think maybe it kind of unscrewed, or was never tight, in the first place? Just sitting there absorbing each compression blast. That makes more sense than if it was seated properly. I mean, an oxy acetylene torch aimed up from the inside couldn't do a much better job.
You know, it would be interesting to search the 'net and see if that was a one in a million occurrence or rather more common? I'm thinking rare, meteor strike rare. Maybe Popular Mechanics wants to talk to you?
Good hunting. El Bee
Posted by DAA (Member # 11) on February 22, 2019, 12:05 PM:
Your guess is as good as mine. I really don't know what happened.
Talked to a couple Toyota guys, tons of experience with this motor (2UZ-FE), neither has seen anything like it either.
- DAA
UBB.classicTM
6.3.0