Mobile Helicoiling Block in South East?
Discussion
Morning All,
Does anyone know a good mobile guy (or girl) who can heli coil an engine block.
Basically a headgasket failure has caused the head studs to pull the threads out 2 of the holes on the exhaust side. I have spoken to someone who can do it, and has said he would want to heli-coil the every stud hole (scuse the non technical words) however i don't think he will be able to do this for a while.
Its a 6-Cylinder BMW engine, all stripped down but still in the vehicle.
Many thanks
Rob
Does anyone know a good mobile guy (or girl) who can heli coil an engine block.
Basically a headgasket failure has caused the head studs to pull the threads out 2 of the holes on the exhaust side. I have spoken to someone who can do it, and has said he would want to heli-coil the every stud hole (scuse the non technical words) however i don't think he will be able to do this for a while.
Its a 6-Cylinder BMW engine, all stripped down but still in the vehicle.
Many thanks
Rob
As Steve said, it's cheaper to buy a kit and DIY. Under £20 inc p&p on fleabay
http://cgi.ebay.co.uk/Silverline-Helicoil-Thread-R...
http://cgi.ebay.co.uk/Silverline-Helicoil-Thread-R...
Helicoils do a job, but these are better
http://www.timesert.com/
Far better than a square section coiled wire insert. Try phoning around some engineers merchants.
Chris.
http://www.timesert.com/
Far better than a square section coiled wire insert. Try phoning around some engineers merchants.
Chris.
Helicoiling critical threads in situ when the thread needs to be absolutely vertical isn't a fun proposition. I've seen the results of people trying this with bolts ending up sticking out at 10 degrees to the component face.
If you try it then you need a jig to hold both the drill and the tap straight. This is just a piece of scrap metal a couple of inches across and 1.5" thick with a close fitting hole drilled through on a milling machine so it's properly vertical. You can hold this on the block face, or a second pair of hands can, to keep the tool in line. Make one for the drill bit and another that the tap just fits through. Once the tap has cut the first few threads you can continue without it but getting the tap started straight is the critical bit.
If you try it then you need a jig to hold both the drill and the tap straight. This is just a piece of scrap metal a couple of inches across and 1.5" thick with a close fitting hole drilled through on a milling machine so it's properly vertical. You can hold this on the block face, or a second pair of hands can, to keep the tool in line. Make one for the drill bit and another that the tap just fits through. Once the tap has cut the first few threads you can continue without it but getting the tap started straight is the critical bit.
Pumaracing said:
Helicoiling critical threads in situ when the thread needs to be absolutely vertical isn't a fun proposition. I've seen the results of people trying this with bolts ending up sticking out at 10 degrees to the component face.
If you try it then you need a jig to hold both the drill and the tap straight. This is just a piece of scrap metal a couple of inches across and 1.5" thick with a close fitting hole drilled through on a milling machine so it's properly vertical. You can hold this on the block face, or a second pair of hands can, to keep the tool in line. Make one for the drill bit and another that the tap just fits through. Once the tap has cut the first few threads you can continue without it but getting the tap started straight is the critical bit.
I drilled and tapped my RV8 for 1/2 studs once, using an electric drill and a cheap £30 drill guide/stand lol.If you try it then you need a jig to hold both the drill and the tap straight. This is just a piece of scrap metal a couple of inches across and 1.5" thick with a close fitting hole drilled through on a milling machine so it's properly vertical. You can hold this on the block face, or a second pair of hands can, to keep the tool in line. Make one for the drill bit and another that the tap just fits through. Once the tap has cut the first few threads you can continue without it but getting the tap started straight is the critical bit.
First few turned out straightish....cant say they all did !!! But I got them all tapped to 1/2" in the end and fitted the studs.
next problem....getting the cylinder heads on with angled studs LOL
Block of wood and a hammer soon sorted that. No easy feat I must add.
But when the engine eventually came apart a year or so later after I melted a few pistons on the Isle of Man.
The heads lifted off no problem. I guess the tension sort of worked them straight lol
Have you seen anyone as rough as that before
Max_Torque said:
The late great Keith Duckworth was a great fan of angle head studs........ Although i suspect he might have used a more precision approach ;-)
If I was a more patient sort of individual, they all might have turned out straight lolSadly, I'm not.
Either way, they still would up to 120lbft no problem, and never once did the head gasket give a sign of letting go.
Just a pity I blew the crap out of it instead over the mountain on the Isle of Man. I think my passenger was glad though !
The sensible answer is don't try it. It might be a pain and time consuming but the best advise is remove the bottom end, strip it and take the block to someone who can do this properly on a milling machine. It will be a good opportunity to rebuild the bottom end, fit new bearings and whatever else might be needed. If I wasn't semi-retired I'd offer to do it but I'd rather help than see you destroy a good engine with poor workmanship. If you can't find anyone else I'll try and help.
BTW, I see no point in helicoiling the threads that are still good despite what the person you have already spoken to has said. That's just making work for work's sake.
BTW, I see no point in helicoiling the threads that are still good despite what the person you have already spoken to has said. That's just making work for work's sake.
Pumaracing said:
The sensible answer is don't try it. It might be a pain and time consuming but the best advise is remove the bottom end, strip it and take the block to someone who can do this properly on a milling machine. It will be a good opportunity to rebuild the bottom end, fit new bearings and whatever else might be needed. If I wasn't semi-retired I'd offer to do it but I'd rather help than see you destroy a good engine with poor workmanship. If you can't find anyone else I'll try and help.
BTW, I see no point in helicoiling the threads that are still good despite what the person you have already spoken to has said. That's just making work for work's sake.
When they go, generally all the threads are damaged to some degree.BTW, I see no point in helicoiling the threads that are still good despite what the person you have already spoken to has said. That's just making work for work's sake.
Best to do them all so you dont find out one isnt any good when you come to torque the head down again.
Seems to be very common on those BMW's
Ive heard from a BMW tech of some of these suffering long radial cracks starting at the rear stud holes which is what they reckon makes the threads fail initially.
If the cracks are long enough,into the coolant galleys then
inserts or helicoils become an expensive way of getting the bolts to stay in and little else.
they dont appear cold but apparently are hard to miss once the block is heated.
If I had a list of all the cars Ive seen with repeat h/g failure (apart from the rover k series,though thats usually through lack of understanding) BMW six`s would feature a lot.
If the cracks are long enough,into the coolant galleys then
inserts or helicoils become an expensive way of getting the bolts to stay in and little else.
they dont appear cold but apparently are hard to miss once the block is heated.
If I had a list of all the cars Ive seen with repeat h/g failure (apart from the rover k series,though thats usually through lack of understanding) BMW six`s would feature a lot.
Been there and done that (not a BMW block, but an SBC). Helicoiling, in principal, is very simple... you just drill an appropriately-sized hole for the insert, tap it and screw the insert in. However, you MUST make sure the hole is drilled absolutely perpendicular to the block deck and ensure the tap is started dead straight. This is virtually impossible to do with an engine in-situ, but it is possible to make a fixture as already mentioned to guide the drill in straight. For that, you'll need a pillar drill / drill press. If you're feeling lucky and have good eyes, you can do it freehand, but you'll need a helper... you can take care of the vertical axis and your helper should stand 90* from you and look along the x (horizontal) axis to make sure you're going in straight. You'll probably need to use a combination of using a fixture and drilling freehand, as access constraints often mean using a fixture isn't always possible. The likelihood of success when attempting this repair freehand also depends on the length of the threads you need to drill and tap... the shorter (less deep) the hole, the greater margin of error you're afforded. Also, be vary careful of swarf. Turn the tap slowly, 1/4 turn at a time, then back it up and go in another 1/4 turn until you're done. Keep the tap well lubricated with cutting oil (don't use WD40 or engine oil... the tap needs a good EP lube to cut the threads).
Personally, I'd pull the engine and take it to a machine shop to be helicoiled. They can mount it on a jig and drill the holes perfectly straight. If you try to do this in-situ and get it wrong, you'll turn your block into a lump of scrap aluminium.
Best of luck.
Personally, I'd pull the engine and take it to a machine shop to be helicoiled. They can mount it on a jig and drill the holes perfectly straight. If you try to do this in-situ and get it wrong, you'll turn your block into a lump of scrap aluminium.
Best of luck.
ian_uk1975 said:
Personally, I'd pull the engine and take it to a machine shop to be helicoiled. They can mount it on a jig and drill the holes perfectly straight. If you try to do this in-situ and get it wrong, you'll turn your block into a lump of scrap aluminium.
Best of luck.
of course...that assumes the machine shop will actually do that !!Best of luck.
Ive seen tapped holes in pieces made by a machine shop, that are worse than I could have done at home !!
I was raging, if I had known they were just going to let a dummy tap them by hand, I'd have done it myself.
Even more annoying seeing as they made the pieces for me in a lathe in the first place ! How hard would it be to thread in a lathe ?
stevieturbo said:
of course...that assumes the machine shop will actually do that !!
Ive seen tapped holes in pieces made by a machine shop, that are worse than I could have done at home !!
I was raging, if I had known they were just going to let a dummy tap them by hand, I'd have done it myself.
Even more annoying seeing as they made the pieces for me in a lathe in the first place ! How hard would it be to thread in a lathe ?
I should've said... take it to a GOOD machine shop!Ive seen tapped holes in pieces made by a machine shop, that are worse than I could have done at home !!
I was raging, if I had known they were just going to let a dummy tap them by hand, I'd have done it myself.
Even more annoying seeing as they made the pieces for me in a lathe in the first place ! How hard would it be to thread in a lathe ?
I'm friendly with my local place... been going there for years on and off and they're excellent. The owner is a car enthusiast as well as a good engineer and he always shows great attention to detail.
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