MR2 Roadster Owners Club

The Workshop => Maintenance, Problems & Troubleshooting => Topic started by: tinky1 on November 21, 2009, 00:06

Title: Helicoil Hell
Post by: tinky1 on November 21, 2009, 00:06
Attempted to helicoil the middle bolt on the head to manifold.

All went well until the tap snapped inside the head, about  1.5 cm left inside.

this tap was brittle as F@@@/., and i am livid.

Any ideas on who i can take it to fix in the North east?  rang a couple of places and they are saying " head needs to be removed"

Got the manifold back on as it snapped pretty level, so can drive.
Title: Re: Helicoil Hell
Post by: normanh on November 21, 2009, 00:50
Its possible to get tape extractors that put 2 or 3 thin fingers into the tape flutes depending on the tape used to remove the broken bit. Its just turned out in a wrench. Its worth chatting with your local engineering equipment supplier, not cheap but then taking the head off isnt either.


normanh
Title: Re: Helicoil Hell
Post by: Cap on November 21, 2009, 05:27
You are Kinda Fubared on this..   But I've done it..  Not on the Spyder, but other stuff..  

I hope there is not going to be a Language Problem, as we call things different Across the Pond..  

The Broken Tap is VERY hard..  you will need a Carbide Drill, to get it out..  The Fastest Source for a Carbide Drill, is the Hardware store /Home Improvement Store..  Carbide Drills are used for Drilling into Concrete and Bricks..  this Carbide will work..  It's not sharpened properly from the Factory, but is good enough for our use..  we are going to destroy it anyway, so get a few of them..  

I'm thinking 'We' can use the Existing Manifold as a Guide to align the Carbide Drill..  Get a Carbide Drill ( A Few of them ), that is the Same Size as the Manifold Bolt  hole..  this will prevent the Drill from 'Walking' side to side into the Softer Aluminum head.  

Remove the Back Bumper and the Exhaust Muffler, ( Easy to say fro my Side! ) so you can get a Drill and Motor 'Directly' in front of the Broken Stud..  Should take you about 1/2 Hour to get that stuff off..  Provided you do not break any more Bolts..  REMEMBER, use penetrating Oil on the Exhaust Bolts..  let it sit for a few days, if necessary..    To soak in..  

Get a Comfortable Spot to do the Drilling..  thats why 'We' pulled the Exhaust System out of the Way..  Must be able to see what is happening AND be able to PUSH really hard..  NO KIDDING. we are talking HARD..  and Straight..  

Use the Drill Motor, Carbide Drill ( Proper Size ) and Cutting Fluid..  Drill Slowly and Press Hard..  it will go through the Tap..  Do not Spin the Drill very fast at First, or you might break off the Sharp Edges before it has time to start cutting..

The Problems that you will encounter, is the Tap Pieces 'Wiggling'..  as the Carbide Drill passes over the 'Edges' of the Tap..  this will break off the Sharp Corners of the Carbide Drill..  You will notice that the Carbide will just 'Stop Cutting'..  It's Dull, Get another one, Try Again..    You might use 5 or 6 drills to be able to get the tap small enough to ' Crumble Out'..  It's not going to be Pretty!..  But it will come out..  If you have a Bench Grinder, you might be able to put somewhat of an 'Edge' back on the Carbide Drill.. and reuse it.. You really should have a 'Green Wheel' stone to Sharpen Carbide..  But I've done it on the Regular Grey Wheels..  It just takes off a lot of the Wheel..  

Persistence will get the piece out..  If any of the Tap, is sticking out of the Head..  Grind it flush..  and Flat.. this will give the Drill a Chance to Start Straight..  

I have Drilled out Broken Taps..  'Easy Outs' and the Hardened Pins used on Flywheels..  They will come out, You just need to be able to Push Hard and Straight..  and use Sharp Carbide..  

Good Luck..  

Cap
Title: Re: Helicoil Hell
Post by: Anonymous on November 21, 2009, 09:23
If the tap is flush and visible you could try using a needle punch and small hammer, find an edge and gently tap in an anticlockwise direction to get it out.
Title: Re: Helicoil Hell
Post by: normanh on November 21, 2009, 13:20
My own feeling is that in situ drill out a tap with a carbide drill is frought with danger, the main problem is the drill wandering leaving you with a real messy hole. A needle punch is tried and tested route to take as often you are lucky enough to find the tap loose in the bottomed out hole after a couple of trys with the punch. Heres a link that might help-

 m http://www.metalartspress.com/PDFs/Remo ... teners.pdf (http://www.metalartspress.com/PDFs/Removing_Frozen_or_Broken_Taps_and_Fasteners.pdf) m

Good Luck.

normanh
Title: Re: Helicoil Hell
Post by: ChrisGB on November 21, 2009, 22:37
Quote from: "Les"If the tap is flush and visible you could try using a needle punch and small hammer, find an edge and gently tap in an anticlockwise direction to get it out.

That would be my first approach. Drilling with a bit that is the size of the hole in the manifold will result potentially with an oversize or odd shaped hole.

Taps are hard enough to cut steel, so they are normally brittle. Always let the tool do the work and keep it lubricated when tapping. Late advice, but good for next time.

Chris
Title: Re: Helicoil Hell
Post by: tinky1 on November 24, 2009, 20:14
Thanks for your help guys, will give the punch a go at the weekend, the drilling is a step to far for my skills, so if no joy will take it the rebore engineer in the toon.

Thanks
Andy
Title: Re: Helicoil Hell
Post by: tinky1 on November 25, 2009, 21:50
Hi Guys,

Managed to work from home this afternoon and have had a crack at this with the punch.

The ends of the tap were very brittle but it wouldnt turn, however only about 7mm left inside.

Any ideas of a tool to twist this, or shall i continue with the punch and hope the rest is as brittle?

(http://i966.photobucket.com/albums/ae141/tinky1_bucket/IMG_5560.jpg)
Title: Re: Helicoil Hell
Post by: Anonymous on November 26, 2009, 00:57
Looks a mess to me!  Take it to an engineering shop and get the job done right.  Helicoils can be a bugger to get right without breaking taps as well (did you use a plug tap?) I did a Landrover once and that was a swine with a cast iron head and City&Guilds Mechanical Engineering qualification.
Title: Re: Helicoil Hell
Post by: tinky1 on November 26, 2009, 01:07
Yoyo - totally agree tis a mess and getting worse but all the guys in the North East want to the head on a bench!
I have no immediate  rush to fix this so still hoping for some drive in or mobile saviour!!!
Title: Re: Helicoil Hell
Post by: Cap on November 26, 2009, 02:11
Nice Photo..  Lets me see what you have..   Looks like your 'Run of the Mill' broken tap..  The 'Good Thing' is, you can get to it..  Sometimes you can't..    Good thing is you can take your Time..  that helps..

I have used a Pair of 'Long Nose' needle nose Pliers..   See if you can find a pair.. and use them as a Tap Extractor.. I have gotten A few taps out by Lubricating the Threads with oil, and wiggling the Tap back and forth ( Sometimes it might take a While ) and work the 'Chuncks' of the Aluminum threads out from the Sides of the Tap..  Then  you might be able to screw the tap out..  

Some persistence and Use of the Hammer and Punch should reduce the Tap to removable Pieces..   You are Probably going to have to use a 'Full Body Insert' to replace the threads with..  as the hole is going to be too big for the Heli-Coil..  I don't like Heli-Coils any way..  they are too easy to Cross thread bolts into, as the 'Start is Wrong'..  and Sometimes in High heat Situations, the Coil will come out with the Bolt..  

Trick with taping..  On a Tap that you 'Can not Break'  ( You can Break any tap, but if it's a Tap that will cause you Great Deal Of Grief if you do )..  Turn in 1/2 turn, then out..  then go in 1 turn then out all the way..  then go in 1 1/2 turns then Out all the way..  Countuine adding 1/2 turn each Time..   I use this technique when starting..  To get a Feel as to how well it going to cut..  

Good Luck..  

Cap
Title: Re: Helicoil Hell
Post by: normanh on November 26, 2009, 19:12
Hi again tinky1 please refer to my earlier post it describes exactly the tool you need to try and use, its none of my business but if you chose to ignore advice that is good its up to you. I dont know why I bother!!!!


norman
Title: Re: Helicoil Hell
Post by: Anonymous on November 26, 2009, 19:28
You could try this:   m http://cgi.ebay.co.uk/Broken-tap-remove ... _707wt_939 (http://cgi.ebay.co.uk/Broken-tap-remover-Emergency-work-recovery-tool_W0QQitemZ300370088469QQcmdZViewItemQQptZUK_BOI_Metalworking_Milling_Welding_Metalworking_Supplies_ET?hash=item45ef73d215#ht_707wt_939) m
Title: Re: Helicoil Hell
Post by: tinky1 on November 26, 2009, 19:31
Norman, thanks i do appreciate your help and have been spending my afternoon trying to source the tool your link mentions..

Thanks again when i get this tool i am sure it will get it out   s:D :D s:D
Title: Re: Helicoil Hell
Post by: ChrisGB on November 26, 2009, 23:28
Quote from: "tinky1"Norman, thanks i do appreciate your help and have been spending my afternoon trying to source the tool your link mentions..

Thanks again when i get this tool i am sure it will get it out   s:D :D s:D

Cromwell tools again:

http://www.cromwell.co.uk/static/publication/547/pages/176.pdf

Chris
Title: Re: Helicoil Hell
Post by: tinky1 on November 27, 2009, 17:47
Cheers Chris GB, ordered and on way. Hope your on commission mate!!

Thanks
Andy
Title: Re: Helicoil Hell
Post by: ChrisGB on November 28, 2009, 00:09
Quote from: "tinky1"Cheers Chris GB, ordered and on way. Hope your on commission mate!!

Thanks
Andy

Just used them as a useful and very well stocked supplier for years.

Chris
Title: Re: Helicoil Hell
Post by: tinky1 on December 17, 2009, 17:02
Update - Got the B@@@@@D tap out finally, first set of extractors were 8mm and snapped like dry spaghetti, got the next size up and worked like a dream within a couple of mins.

Got the Helicoil in and the bolt has a nice and tight fit and no blowing or leaks from the manifold.

Thanks to all above for your advice, much needed and much appreciated - merry Christmas.

Tinky1
Title: Re: Helicoil Hell
Post by: muffdan on December 17, 2009, 17:24
it's been epic. Glad to hear its all sorted.
Title: Re: Helicoil Hell
Post by: Wabbitkilla on December 18, 2009, 08:00
 s:D :D s:D   Excellent news well done, this should serve as a good lesson to anyone facing a similar drama
Title: Re: Helicoil Hell
Post by: ChrisGB on December 18, 2009, 11:14
Given the effort required to break a tap and in this, case to remove it, the key pointers for anyone undertaking this sort of job should be:

Take caution to not subject the tap to bending forces.

Use cutting oil.

Do not force it, cut the thread a little at a time with minimal force.

Clear swarf often.

Chris