Omega Owners Forum
Chat Area => General Car Chat => Topic started by: omegod on 02 July 2011, 18:00:46
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Well the bargain 728i bought appears to have a hidden horrors! It was misfiring so I suspected a dodgy " pencil" coil pack, on removing them number 5 is melted/burnt/destroyed and lo and behold the plug beneath is in a helicoil that appears to have worked it's way out with the helicoil, amateur effort by the looks of it.
Anyhow it's life now hangs in the balance, I can break it and make some cash as I paid buttons for it but it's that nice I would rather see if it can be revived. The thread appears non existant in the plug well which is odd as helicoils need a thread to wind into.
So! can it be recut and an oversized helicoil/time sert be fitted? and could this be done in situ?
Any suggestions of a decent place/person in the North west?
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could re-do the helicoil i imagine. if there is no thread there then that suggests an amateur job as you say, like someone has knocked the helicoil in somehow.
It would come almost straight out of course. but who knows.
Either way, i dont see why you wouldnt be able to do it again.
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as for doing in-situ,
Might be more difficult as the little "tang" ont he end of the new heli coil would need to be tapped through....you might be able to pull it out instead of tapping it through, but that would be awkward.
Other than that, you're going to have metal swarf/shavings from the new thread being cut.
So.......
unless you have a way of stopping that going into the engine..
You'd have to do it off the car.
Would be nice to save it.But unless you can do it on the cheap, it may be better to break or try to sell on whole.
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I remember reading about someone filling the cylinder with squirty cream, doing the helicoil then spinning the engine over to spit it all out of the plug hole ;D it worked but I don't fancy it myself!
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If you do this, make sure the valves are closed on that cylinder as had to remove the head on a Carlton once when someone had decided to retap the plug hole and tapped a thread into the valve. Needless to say it didn't run well.
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Unless you can turn the engine upside down to tap the plug hole, the swarf will fall into the bore and cause you another problem a bit later.
The head needs to come off at the very least. Can't you get a s/h head? I know it's a pain but having a plug come out when you're driving can be disconcerting to say the least. ;) Of course you may be proposing that that calamity happens to someone else?
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Sorry to hear this... It's a good bet the seller knew as well, considering the price >:( >:(
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Given that one attempt to helicoil has failed, would it not be a better bet to bite the bullet and have a look for a decent head?
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Its going to be a "head off" job whichever route you take to try to fix it. I would agree that another head is the way forward.
Dont know how much a good head would be from a breaker, but to do all that work and still have the possibility of the same thing happening again to the old head..... ;)
I think it would be worth doing the job properly, as imo its a gorgeous car. :y
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Been thinking about this and have had an engineer say he is confident he can do it for £40, albeit with the swarf risk on my head be it, apparently it's an ally head so magnets wont clear it. Apparently pulling the head off opens up a gammut of other issues as the head bolts usually strip their own threads when torquing them up i.e more bloody helicoils or new complete engine. The existing helicoil doesnt appear to have been drilled or tapped in and more like some numpty has threaded a helicoil onto the plug and tried to stuff it in the head. I will update as I go forth with this one!
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just areldite it in then flog it quick. :y
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just areldite it in then flog it quick. :y
Mental note - never buy anything from R1. ::)
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just areldite it in then flog it quick. :y
My conscience wouldn't let me do that R1, it only owes me £450 and I think the wheels are worth that alone.
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you could prob pick up a good second hand engine for around 200,300 quid as its a 2.8 same engine as any 3,5 or 7.think thats the way id go cos its a lovely car and one of the best bmw`s made.they drive so nice nothing else like em
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This is a viable option i would say if you could swap it yourself.
But if you have to pay a garage to do the engine swap it becomes uneconomical.
As for the Helicoil, I say have a go at it.
Worst that happens is you break....or sell on as a project for the money you bought it for.
no loss
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Helicoils are crap on anything other than something that is bolted up after repair & then never ever touched. Although I've never used a spark plug Time-sert I've used loads of M5 M6 etc Time-serts, their advantage is that the thread is a solid one piece insert that doesn't unwind from the hole.
http://www.youtube.com/watch?v=Ntiy8L97Nco
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Take the risk helicoil it then sell it on the same as a lot of traders do, In a lot of opinions you havn't bodged it,
:y :y :y :y
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Helicoils are crap on anything other than something that is bolted up after repair & then never ever touched. Although I've never used a spark plug Time-sert I've used loads of M5 M6 etc Time-serts, their advantage is that the thread is a solid one piece insert that doesn't unwind from the hole.
http://www.youtube.com/watch?v=Ntiy8L97Nco
agreed on helicoils,no good on threads that will be used again,not come across the time-sert's before but they look pretty good :y
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Helicoils are crap on anything other than something that is bolted up after repair & then never ever touched. Although I've never used a spark plug Time-sert I've used loads of M5 M6 etc Time-serts, their advantage is that the thread is a solid one piece insert that doesn't unwind from the hole.
http://www.youtube.com/watch?v=Ntiy8L97Nco
Agreed time-sert is the way to go ..
http://www.timesert.com/
and specifically for plugs
http://www.timesert.com/html/sparkplug.html
and for previously bodged repairs ...
http://www.timesert.com/html/bigsert_sparkplug.html
:)
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Helicoils are crap on anything other than something that is bolted up after repair & then never ever touched. Although I've never used a spark plug Time-sert I've used loads of M5 M6 etc Time-serts, their advantage is that the thread is a solid one piece insert that doesn't unwind from the hole.
http://www.youtube.com/watch?v=Ntiy8L97Nco
Seen the timeserts Andy but not come across an engineering shop who has said they would have a go, they all seem to be helimad you know anyone who could do it down your way?
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...,not come across the time-sert's before but they look pretty good :y
They're not cheap though. I've a set that covers M5 M6 M8 M10 & M12 which I believe cost my previous employer around £300 ............. part of the redundancy package ::) ::) ::)
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Helicoils are crap on anything other than something that is bolted up after repair & then never ever touched. Although I've never used a spark plug Time-sert I've used loads of M5 M6 etc Time-serts, their advantage is that the thread is a solid one piece insert that doesn't unwind from the hole.
http://www.youtube.com/watch?v=Ntiy8L97Nco
Agreed time-sert is the way to go ..
http://www.timesert.com/
and specifically for plugs
http://www.timesert.com/html/sparkplug.html
and for previously bodged repairs ...
http://www.timesert.com/html/bigsert_sparkplug.html
:)
You were busy Nige! :y :y :y :y
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Helicoils are crap on anything other than something that is bolted up after repair & then never ever touched. Although I've never used a spark plug Time-sert I've used loads of M5 M6 etc Time-serts, their advantage is that the thread is a solid one piece insert that doesn't unwind from the hole.
http://www.youtube.com/watch?v=Ntiy8L97Nco
Agreed time-sert is the way to go ..
http://www.timesert.com/
and specifically for plugs
http://www.timesert.com/html/sparkplug.html
and for previously bodged repairs ...
http://www.timesert.com/html/bigsert_sparkplug.html
:)
You were busy Nige! :y :y :y :y
I try ..... ( or is it I'm trying ?? :) :) :) )
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Seen the timeserts Andy but not come across an engineering shop who has said they would have a go, they all seem to be helimad you know anyone who could do it down your way?
Sorry, afraid not. I only know about the Time-sert plug inserts while looking for the 'normal' inserts part numbers.
Maybe contact Time-sert asking who they've supplied in the Liverpool-ish area :-/ :-/ :-/
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Saw timeserts used a few years back on an Imp engine used for saloon racing. Apparently after a plug change one of them was cross threaded and it "blew", damaging the thread.
Done in-situ and the car was racing again in less than 2 hours.
IIRC the major downside was the cost of the tools.. the inserts themselves were not too expensive ... but the tools .... :(
Re-tapping the hole was done in very small amounts and copious volumes of grease were used to collect swarf .. the guy obviously knew what he was doing.
I "believe" they are considered a DIY method not neccessarily a workshop one .. but the cost of the tools might preclude a "one off" .. :(
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have piston at the top have it tapped and helicoiled
then use hoover with adapted pipe we use 8mm fuel pipe taped to hoover pipe hoover debris out
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..... but the cost of the tools might preclude a "one off" .. :(
but the cost of the Time Sert tools vs the price of A N Other head and fitting it etc :-/ :-/ :-/
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there are a few spark plug Time Sert kits here .... but as said, they're expensive.
http://shop.ebay.co.uk/i.html?_nkw=time+sert&_sacat=0&_odkw=plastic+welder&_osacat=0&_trksid=p3286.c0.m270.l1313