Drilling out cylinder head studs

[knocker]

So this is a continuation of my other posts about getting the cylinder head off my divvy.

I eventually ended up removing the engine from the bike and taking it into work so I could attack it properly as it was sticking on what I thought was one of the dowels. Anyway, after cleaning everything up and going at it with everything i've got the head still won't come off and I have discovered why. It would seem that a former owner has had the head off before and has either stripped the hoe that the stud screws into or done some other damage and taken it upon themselves to glue the stud back into the cylinder block but also pack loads of adhesive and other shit in the hole around the stud in the cylinder head.

As a result of this the head is glued solid to this one stud and nothing will shift it, it's been heated, cooled, heated some more. left soaking in some fairly nasty chemicals that tend to dissolve most things put in them, even resorted to welding a nut to the top of the stud in order to try and back the entire stud out of the block but this just resulted in the nut shearing off.

I'm now left with not much option other than to try and drill the stud out but it's not something I have done before. I can make myself a new stud if need be and ahve all the tools and machinery I can shake a stick at but some tips and tricks would be nice from anyone who has done it before.

Really am pissed off, the original snapped spark plug is out and the hole helicoiled but what was a relatively straight forward job has now turned into fairly major engine surgery and i've been nikeless for 2 weeks.

Anyhow, tips and tricks would be welcome or even better alternate suggestions before I start going at it with power tools.

[iooi]

I'm starting to think This maybe a better idea.

By the time you have finished removing and then getting a new stud, and fixing the knackered hole...
It may be a better option.
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Just because my bike was A DIVVY, does not mean i am......

[stinkwheel]

The gold standard would be to get the whole engine clamped to the bed of a big pillar drill or milling machine.

For those of us without such a thing and who don't want to drop out the engine, something I always said I would try if I had to drill a stud out again is to make myself a drill guide. I was more thinking for exhaust studs but I see no reason why a variation of the same idea wouldn't work in your situation. I've not tried this way so you might need a bit of fiddling to get it right

Basically, get yourself a thickish block of alloy. Mark out the hole centres of the studs and drill the holes perfectly square and vertical on a proper pillar drill.

Put the drillguide down over the studs and use hole over the one to be drilled out to keep your drillbit on centre.

Once the head is off, you ought to be able to remove the remainder by more conventional means or use the drill guide again if it wont come.

If it won't come out of the block, it's perfectly possible to re-tap the hole slightly oversize, then turn down the top part of an oversize stud to fit. Or even drill out the head slightly oversize to suit the stud providing you aren't going to interfere with any oilways.

Obviously fabricating the body of such a drillguide may need a wee bit of thought so it fits over the various cylinder head gubbins. I envision some sort of L-shaped piece of metal that fits over a stud on either end of the "L" with the drill guide part in the angle of the "L". Might need bits cutting out in the area between the holes so it doesn't foul anything.

Just a thought. As I say, my original idea was to use this to drill out an exhaust stud which would only need a simple block with three holes in it.

Actually. Check out this picture of someone drilling the block on a cadillac engine:
https://pic80.picturetrail.com/VOL827/1543635/18343004/310895933.jpg
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Ichy]

You could actually improve on the idea Stinkwheel. If the stud is proud of the surface you could drill entirely through the block your using for the drill guide with a drill say half the diameter of the stud. Then drill half way through the block with the correct size drill for a tap the same size as the drill. Tap it out then you have a sleeve that screws onto the stud or over the remains of the stud. Dead center without the need for a clamp.

Bit rough arsed but there you go.
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[knocker]

Cracked it.

I've only had to drill the top threaded part of the stud off and the head is now off the engine.

I'm planning on taking the rest of the block off in the morning so that I can remove the rest of the stud, re=tap it and put another one in. All being well everything should be back up and running within a week.

Amazing how a relatively straight forward job such as removing the head can turn into an absolute nightmare lasting 2 weeks, at least I can now see some light at the end of the tunnel.

Thank f*** for that.

[Pete.]

If it's been glued in with metalmender/araldite/JBweld you will be able to remove it by heating the area locally with a plumbers torch. The glue will soften and melt before the alloy. Rub some soap on the alloy to keep a check on the temperature - if the soap turns black you're gonna melt-down.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good