No worries on the hijack - food for thought and really appreciate your kind offer - what is that kit BTW - may make an investment myself.....the rear bushes are the least of the problems and can wait a short while - need to get the head off first.

I have looked and looked again over the weekend and I will get the cam cover off later today (I hope if I can nip out from work early enough) and see if there is more room, I have big hands and I can just get my hand in between the ABS ECU and the head to just get my finger tips on to the top of the plug in that tight space. So doing a thread repair in-stu could be nigh on impossible for me....which means head off.

Would love to do the guides and VANOS etc while I am going this far - but after talking with the other half, and our current financial situation, I will get the car running again, and then save up for the rest of the kit....as I don't need to pay for labour, I don't mind stripping and putting back together, and then stripping again to do further work....just need her up and running at the moment.
 
Fair one mate, I would think if you can get a spark plug socket on it you should be able to get the thread cutting tool on it but it's whatever you feel comfortable with of course.
I bought that bush kit when i did my rears and it looks cheaper now than when i got it as mine was £99.99 but looks like they are around £70 now on the bay.
This is the one i have.
http://vi.vipr.ebaydesc.com/ws/eBay...descgauge=1&cspheader=1&oneClk=1&secureDesc=0
 
Looking at the tool with the thread at the front to follow in what is left of the existing thread then i would think that would prevent any swarf going forwards to start with and then if you wind the tool in to start cutting the new thread like Alan says with plenty of grease of cutting compound on it I would think that would catch any swarf, you could also fit a small pipe to a hoover and have that running beside the tool or at intervals and into the bore afterwards.

I'm sure there are plenty of examples on the net.

If you cut the thread and inspect the bore afterwards, if you are not totally happy then you can take the head off anyway.

Cheap borescopes are available for small money, i have a couple that run off a laptop and the image quality is very good.

If you go with the helicoil you would need to make sure that you can get in with narrow nose players and break off the drive tang from the bottom of the thread and from memory you can get tangless inserts to save you having to break the tang off afterwards and risk dropping it in the bore. Being stainless it may not be magnetic but the blob of grease on the borescope worked for me or a small pickup tool with grab that comes out the end but best not to drop it in the first place.

A helicoil needs a certain type of thread cut so you would need to get the matching tool to suit the insert or you would need to drill and tap using one of the kits but that would be more tricky.

This is the type of thing but check you have the correct length of insert to suit your head and the thread is correct. i have a couple of heads in my garage if you want to check any dimensions.
This tool has the pilot thread on it.

https://www.recoilshop.net/spark-pl...MItrXklbbT3QIV7JztCh2GNgmEEAQYAiABEgKS0_D_BwE
 


Had opportunity today to whip the Cam Cover off and take a closer gander.

As per @biketeacherdave good friend Johns suggestion, there is more room with the cover removed, Still not a huge amount, but much better.

I may just be able to get the thread tap in that gap, and with luck maintain control.

My chief concern is swarf.....I have heard of peeps filling the bore with shaving foam and then sucking it out with a vac afterwards, using grease or cutting compound on the tap to capture swarf etc.....

My only concern is if using a Helicoil - breaking the tang off the end. Or if using a tang-less insert, the security of such. We all know the name Helicoil - I am concerned that another brand without a tang will not be as good!
 
My machine shop poo poo the helicoil brand for some reason,
maybe it's been bettered, as in tang-less?


Anyway, good luck on your endeavours.
 
Saint.V8 said:


Had opportunity today to whip the Cam Cover off and take a closer gander.

As per @biketeacherdave good friend Johns suggestion, there is more room with the cover removed, Still not a huge amount, but much better.

I may just be able to get the thread tap in that gap, and with luck maintain control.

My chief concern is swarf.....I have heard of peeps filling the bore with shaving foam and then sucking it out with a vac afterwards, using grease or cutting compound on the tap to capture swarf etc.....

My only concern is if using a Helicoil - breaking the tang off the end. Or if using a tang-less insert, the security of such. We all know the name Helicoil - I am concerned that another brand without a tang will not be as good!
Click to expand...



I'd pull the head and do it on a bench if i was in your position..

I wouldn't want to risk getting swarf into the motor..

;)
 
I wouldn't be overly worried about swarf.........

you've prolly got plastic shrapnel in the sump anyway if your guides are going south.
 
Helicoil & Hoover.... or Tangless and Tango. ;)

You are just itching to do this....we can tell.
A bore-scope and a good inspection after vacuuming out should give you confidence to fire it up.
If you want absolute guarantee of no damage its "Head-off" to do it though.

We have faith in you.
 
Helicoil have a tang free system comparable to the recoil, recoil have been around a long time as we were testing them alongside the helicoil probably 15 years ago or more, the helicoil used to come out favourite because of the name as much as anything. The tang is notched so you only need to grip it with a pair of narrow nosed pliers and give it a turn and it will break off. The tang is only to drive the insert. i think it was the helicoil that had a pre loading tool where you wound the insert onto the tool to expand it and the screw it in to the thread and then wind the tool back out again.
There are the time-serts as another option but I have only seen the kit and they look a bit more involved but will screw into a shoulder and stop rather than the wire inserts that are 'free running'

Whether you take the head off or not, you are still going to need the tools so i would get them and go from there.

if i was doing it i would get the pilot threaded tool and coat it in cutting compound and start to wind it in and cut the first few threads, bring it out and clean it, same again but going a little deeper and repeat that until the thread was to depth. i would also have a vacuum connected to a piece of 12 mm clear pipe and have that running next to the tap at all times ready for when you wind the tool out.
Then bore scope to double check nothing has got into the bore and vacuum out if required and then if still concerned, whip the head off.

Helicoil tang free system

https://www.boellhoff.com/gb-en/products-and-services/special-fasteners/thread-inserts-helicoil.php

These guys looked pretty clued up when it comes to thread repair, there is an interesting expanding repair tool but i think that is only for chasing the original thread and they sell Keen Inserts that look like time serts. I would give them a call and pick their brains.
http://www.knighton-tools.co.uk/acatalog/Thread_Repair_Kits.html
 
You could turn the tap half a turn, back of a quarter to break the swarf and insert the vac pipe over the tap tool and into the plug bore and go again. If you do it with the inlet or exhaust valve open it will give a rush of air up past the tap, maybe..
 
Wind the piston up to tdc and squish a rag into the hole. Drill, tap and pull it out while using a greased lollipop stick to catch the crap, you can do this your eyes shut!! Quit pithing about...o_O:p
 
Saint.V8 said:
The other concern is swarf in the bores of course.....hmmmmmm
Click to expand...
@Saint.V8, use lots of grease on the tap, piston @TDC, go carefully to make sure the tap starts square to the seal surface, sticky screwdriver to poke about in there when finished pretty routine job, I've done job this job a couple of times on Jag XK engines .
The only real risk from alloy swarf is the valve seats if a bit happens to get onto the seat and trapped, but it had not happened in the XK's, any left would blow out with exhaust and because it's soft would not harm bores.
 
FWIW, our company has used various forms of thread-repair products over the years. In our experience, nothing comes close to the products sold under the FullTorque brand. They employ a patented claw-shaped thread which serves to strengthen the material around the repair, rather that weaken it. It's no snake oil and we have never seen one of these back out. I've never used their spark-plug inserts, but they work on the same principle and I wouldn't hesitate to use them. Also, I wouldn't worry much about aluminium swarf. Whatever you can't pick up with with a vacuum and some bluetack on a stick, will be blown out of the exhaust or consumed in combustion. Piston rings and coated bores will not be easily damaged by small particles of soft aluminium. Like others have suggested, use plenty of tapping grease (like Rocol compound) on the tap to catch as much as you can. The pilot drill can be wound in by hand, so you don't need to worry about access with a machine. For safety, you could have a machine shop turn an adapter for you, which uses the spark plug well as a guide, with a hole for the drill bit on one end (with grub screws) and a hex-head on the other. That way you can wind in the drill with a ratchet and socket. The same procedure could be used to guide the tap. You can check the FullTorque system here: http://www.lns-sea.com/ft-spark-plug-inserts.htm
If you want to use a more readily available kit, TimeSert is our second favorite and I have personal experience with their spark-plug inserts, which I used on my old Alfa with great success (didn't remove the head and used only a vacuum to get the swarf out. Compression still perfect a year later).
Hope this helps and wish you luck!

Henrik
 
holidaychicken said:
Even the bores are aluminium on these buggers !
Click to expand...
Thinking they had iron liners in a aluminum block, the same "clack,clack" ones that put an end to many a Rover V8.
Oh, hang on this is that filthy bosch BMW thingy, but even they would be "nickasil" or something.
Still cant imagine any or significant damage from tiny bits of swarf even with that.
 
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