Messed up - What bits do I need now?
Turbo Mini Forums

I tried to dill out the broken stud from the exhaust housing on my turbo below and made things worse.

I used a pillar drill and put a 3.5mm hole through it and was going to use a grabber to extract it but thought I would apply loads of heat to it first so that it should come out easier.

When I got the grabber on it, it wouldn't bite and upon further investigation, it looks like I have changed the makeup of the metal and it is now tough as anything and I cannot do anything. I have tried to drill it out further but the drill bits just blunt

Before I take it to a professional, anyone got any ideas? What type of drill bits should I look at getting that will go through it?

Speed doesn't kill, suddenly becoming stationary, now that's what'll get ya!

Well, Fair do's for trying to get it out,

I would suggest just leaving it, IMO the remaining five bolts should be ok.

Its a tricky thing to do if you haven't done it before...It should drill out but you may have to keep re sharpening the drill bit.

What kind of drill bit are you using? And what speed? High speed steel is what you need a carbon steel bit won't touch it! If its hard then go for a slow speed to prevent the drill from skidding, if it starts squealing the drill bit isn't sharp enough.

You will have to drill it right out to the core depth and run a tap down it. Ive never had any luck with easy outs, and if they break off it will make things worse!

To drill it out to the core size (6.8mm for M8) you will need to drill in exactly in the centre to prevent drilling out the original thread when you go to the final size of drill.

Its difficult to explain but the centre of the stud will not be exactly in the centre when you look at it as you have to take into consideration the thread that you can see. (eg one side of the stud you will see the trhead the other side you will see the thread of the housing). You need to drill it half the thread depth (0.6mm) bias the side part of the stud that you can see the thread on the housing. (looking at the pic its about at 7 O clock) if that makes any sense?

Edited by matty on 9th Jan, 2011.

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1/4mile in 13.2sec @ 111 terminal on 15psi

what matty says below!

depending where a thread breaks off the centre is in a differeint position depending on the thread sticking out, hard to explain, but essentially it goes round in circles...

Oh yeah if you can get hold of a centre drill, that will make it easier to get it in the right place, if the part you are drilling isn't flat.

Joe - I think my explaination made sense...well it did to me! lol

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1/4mile in 13.2sec @ 111 terminal on 15psi

If, as he says, the stud has work hardened with the original drilling, maybe try a masonry drill - but will need a "green" wheel to keep it sharp

TBH, by far the easiest thing to do is take it to a professional who can repair it.

If you are intent on trying yourself, get a cobalt drill bit. It will drill through hardened steel no problems at all.

Or as others say, it's only one bolt, so not the end of the world to run without it.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

If it's a T3, just get a new turbo. I think Brett has one for sale at about £20 needing rebuild. Just use the two to make one good one.

Cheers all, tried to give it another go this afternoon and not much luck.

I will try and take it to somewhere tomorrow and see if they can fix it otherwise I will buy some better drill bits and give it a go myself.

Here's a picture of it at the moment:



I am not having much luck stripping this engine and everything is old and a nightmare to remove. The bolts holding on the thermostat have all snapped off but the housing won't lift off. I assume the to remove these, I should drill them out first? Here's what I am talking about:



apbellamy, cheers for that, just PM'd him.

Thanks everyone :)

Speed doesn't kill, suddenly becoming stationary, now that's what'll get ya!

give the thermostat housing some persuasion with a soft hammer, then you shut be able to use stud extractors on the snapped bolts.

Fire may loosen the thermostat housing

If something is worth doing, it's worth doing half of.

Heating a seized bolt is the absolute last resort. Reason being as you have found once it has been hot it draws the carbon to the surface making it very hard, then difficult to drill.

destroy the top housing with a chizle leaving the studs exposed with some heat and alot ......... you should get some stiltsons on there and be able to remove the studs...