Next problem: stripped spark plug hole + complication
#16
Shameful Thread Killer
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Yeah, cuz there's no such thing as degreaser spray in Scotland. And grease is of course - like glue. Once set, never get.
https://www.livingstonautoparts.co.u...-w54179/W54179
https://www.livingstonautoparts.co.u...-w54179/W54179
#17
Rennlist Member
Oh. I see you don't believe your own dogma? Or are you indulging in a bit of self-flatulence*?
So it's your opinion the OP should just screw in another plug and drive this engine to a shop?
*flagellation? Hard to keep those strait.
So it's your opinion the OP should just screw in another plug and drive this engine to a shop?
*flagellation? Hard to keep those strait.
#18
Shameful Thread Killer
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As for flatulence - what have you contributed? The typical nothing-burger.
#19
Rennlist Member
I recommended towing the car to a shop, given the OP was unwilling to pull the head and attempt the work himself.
You didn't concur, and made noises about driving it to a shop. Where is the confusion? I disagree with you. In fact I consider you a misinformed person on this particular subject even though I have read your contributions with interest and respect in the past. On this subject you are wrong.
Sincerely,
#20
Chronic Tool Dropper
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Keep it civil, friends.
Of course the perfect solution is to flatbed the car to a port, container ship it to Long Beach, and have it transported to Anaheim and Greg B for the work. Meanwhile, the OP asked for recommendations for things he could do short of that, as he doesn't have a local mechanic who can work on it.
Over the years I've observed piston tops and cylinder heads that had enjoyed some small metal bits passed through sometime in their history. Pieces were gone but the damage remained. In this particular case there are several removal methods discussed, and a recommendation to use an inspection camera to verify that all the debris is out. We didn't talk yet about how a simple magnet will grab the steel HeliCoil fragments from the aluminum block and piston. Regardless, so long as it's all removed by whatever method, then the OP is good to continue whatever repair method he chooses.
----
The existing Heli-Coil is a spiral-wound wire, so is easily removable if one can get a grip on one end or the other, then pull it up and out.
To the OP's question of different solid inserts to use -- TimeSert is a known good brand, so it gets the nod from me. There are others, but the others I have the toolbox require that the inside/bottom end be secured by staking and then dressing in the chamber. Or we get to use a threadlocker. More than a minimum percentage of these threadlocked inserts seem to come out with the plugs later if they aren't installed perfectly (read: clean good threads in the head). Read the instructions that come with several of the options and decide which is best for your situation.
Of course the perfect solution is to flatbed the car to a port, container ship it to Long Beach, and have it transported to Anaheim and Greg B for the work. Meanwhile, the OP asked for recommendations for things he could do short of that, as he doesn't have a local mechanic who can work on it.
Over the years I've observed piston tops and cylinder heads that had enjoyed some small metal bits passed through sometime in their history. Pieces were gone but the damage remained. In this particular case there are several removal methods discussed, and a recommendation to use an inspection camera to verify that all the debris is out. We didn't talk yet about how a simple magnet will grab the steel HeliCoil fragments from the aluminum block and piston. Regardless, so long as it's all removed by whatever method, then the OP is good to continue whatever repair method he chooses.
----
The existing Heli-Coil is a spiral-wound wire, so is easily removable if one can get a grip on one end or the other, then pull it up and out.
To the OP's question of different solid inserts to use -- TimeSert is a known good brand, so it gets the nod from me. There are others, but the others I have the toolbox require that the inside/bottom end be secured by staking and then dressing in the chamber. Or we get to use a threadlocker. More than a minimum percentage of these threadlocked inserts seem to come out with the plugs later if they aren't installed perfectly (read: clean good threads in the head). Read the instructions that come with several of the options and decide which is best for your situation.
#21
Rennlist Member
I'll remind you I was emphatically agreeing with a post you'd made right before you wandered into the rough with the assertion they had no grease removers in Scotland, which I took as a backhanded reference to lowland malt whisky...
I was just trying to be a little light hearted Doc, no offense intended. The comment was confusing. I'll use emoticons less sparingly in the future.
#22
Rennlist Member
But I must also say that since the OP was openly concerned over the cost of transporting the car 60 miles to his mechanic on a flatbed, vs. the cost of buying a new engine for the car if a bit of helicoil were missed during an attempt to vacuum out the combustion chamber through the spark plug hole, well, my recommendation to bite the bullet and tow the car, maybe even increase the towing distance on your road service insurance, stands.
#24
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OK, this is the neglected French '79 again. A big hitch has appeared.
Time to change the plugs and ignition leads. The very first plug (front right, cyl 5 I think) - immediately on unwinding the plug wrench I get that unmistakeable sensation of deeply unhappy bolt threads destroying themselves.
So, the threads are stripped
That's OK, I guess I could put in an insert, but on removal of the shrapnel, I see that there is what looks like a helicoil in there (see pic) - I am guessing a previous repair which has not worked.
So if I try to ream this socket and put in an insert I will end up with steel helicoil fragments in the head, which is not going to be great.
So, the head is coming off, right? Am I safe to screw the plug back in best I can, and nurse the car 60 miles to my mechanic? Or is there another way out of this?
Time to change the plugs and ignition leads. The very first plug (front right, cyl 5 I think) - immediately on unwinding the plug wrench I get that unmistakeable sensation of deeply unhappy bolt threads destroying themselves.
So, the threads are stripped
That's OK, I guess I could put in an insert, but on removal of the shrapnel, I see that there is what looks like a helicoil in there (see pic) - I am guessing a previous repair which has not worked.
So if I try to ream this socket and put in an insert I will end up with steel helicoil fragments in the head, which is not going to be great.
So, the head is coming off, right? Am I safe to screw the plug back in best I can, and nurse the car 60 miles to my mechanic? Or is there another way out of this?
Pulling the Helicoil and putting in another is a "used car lot" repair. There's not going to be very much of the oversize threads left for the insert to grab onto. The fact that the spark plug stripped on the way out tells you that these oversize threads are already messed up....otherwise the Helicoil would be perfect and the spark plug would be perfect, right?
The long term correct repair is going to be to pull the head and start over with another head.
All the bickering about doing work on the head with it installed is probably moot. The original repair was probably done with the head on the car....so whatever damage could be done is probably already done.
__________________
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
#25
Addict
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Thread Starter
Thanks everyone. Of course this should be fixed correctly, with a new or correctly assessed and repaired head. It is a beautiful and unique car and I would not be able to afford a full engine rebuild if I killed it.
However, all being equal, if I do a repair with all possible diligence to protect the chamber, then the odds seem to point to the worst that can happen being that the repair fails and the head then must come off. If a turkey has done the previous repair without diligence, no amount of removing the head will fix any damage already done.
The other option from other internet discussions is use of a reverse tap thread chaser - this can be progressively expanded and starts from the bottom up and so does not put material into the chamber, and so may be a low risk way of realigning the misaligned helicoil.
One of these for example:
Foolproof diligence may not be 100% possible, but the odds are made greater by the use of a boroscope camera - so here is the first finding from my £7 investment (thanks for the tip). And so from the land that invented television and a range of fine tasting single malt degreasers, I bring you inarguable evidence of a thread of aluminium sitting against the cylinder wall, and some other damage that I wish I hadn't seen:
However, all being equal, if I do a repair with all possible diligence to protect the chamber, then the odds seem to point to the worst that can happen being that the repair fails and the head then must come off. If a turkey has done the previous repair without diligence, no amount of removing the head will fix any damage already done.
The other option from other internet discussions is use of a reverse tap thread chaser - this can be progressively expanded and starts from the bottom up and so does not put material into the chamber, and so may be a low risk way of realigning the misaligned helicoil.
One of these for example:
Foolproof diligence may not be 100% possible, but the odds are made greater by the use of a boroscope camera - so here is the first finding from my £7 investment (thanks for the tip). And so from the land that invented television and a range of fine tasting single malt degreasers, I bring you inarguable evidence of a thread of aluminium sitting against the cylinder wall, and some other damage that I wish I hadn't seen:
Last edited by Johnny G Pipe; 10-04-2017 at 10:56 AM.
#26
Rennlist Member
I advise the short term but copious use of highland malt whisky. It may not cure the illness, but it should kill the pain...
(for Doc).
#27
Vegas, Baby!
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I have no idea what it would cost, for shipping, but Mark Anderson @ 928 Intl., will have a half price sale on used parts between Thanksgiving and Christmas. I'd buy one of his engines, he backs everything he sells, and do a swap.
You won't get screwed, and you'll be way ahead, in time and money!
You won't get screwed, and you'll be way ahead, in time and money!