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+--- Thread: broken cylinder head stud (/showthread.php?tid=442)
broken cylinder head stud - ollie cox - 11-11-2017
Hi all
putting the engine back together and whilst putting new cylinder head studs in.....one stud snapped flush with the block (stud between no 2 and 3 cylinder). I was trying to put car back together for Cotswold trial. Would it be a wise move to run the car minus one stud. Or is this considered to risky?
thanks for nay help
ollie cox
RE: broken cylinder head stud - Bob Culver - 11-11-2017
Will be more or less end of head gasket, and some risk of internal water leak, perhaps even hydraulic lock. The uneven pressures stress the block and, as with excessive tension, tend to promote cracks. It is largely to avoid this rather than permanent distortion that heads are tightened progressively.
RE: broken cylinder head stud - Charles P - 11-11-2017
(11-11-2017, 12:47 AM)ollie cox Wrote: Hi all
putting the engine back together and whilst putting new cylinder head studs in.....one stud snapped flush with the block (stud between no 2 and 3 cylinder). I was trying to put car back together for Cotswold trial. Would it be a wise move to run the car minus one stud. Or is this considered to risky?
thanks for nay help
ollie cox
Too risky. You'll blow the gasket and have a wasted day!
You really need to get the stud out and replace it. If the engine is in the car it's awkward but doable with careful drilling the centre of the stud and progressively using bigger drills (new, good quality drill bits). When it's almost to the root diameter of the thread I then fold the stud in using a small, sharp centre punch.
Charles
RE: broken cylinder head stud - John Raeburn - 11-11-2017
Ollie,
I'm with Charles on this one, you don't really have an option.
J
RE: broken cylinder head stud - Robert Leigh - 11-11-2017
(11-11-2017, 09:03 AM)Charles P Wrote:To start with a good centre for drilling put the head in place on the studs and choose a drill which is the best fit in the hole of the broken stud, then start drilling into the broken stud just a very little. Take the head off and you will have a good centre in the broken stud from which to start the proper drilling out. You may prefer to put the head back after checking that the start is central, because the head can provide a useful indication that you are keeping the drill vertical.(11-11-2017, 12:47 AM)ollie cox Wrote: Hi all
putting the engine back together and whilst putting new cylinder head studs in.....one stud snapped flush with the block (stud between no 2 and 3 cylinder). I was trying to put car back together for Cotswold trial. Would it be a wise move to run the car minus one stud. Or is this considered to risky?
thanks for nay help
ollie cox
Too risky. You'll blow the gasket and have a wasted day!
You really need to get the stud out and replace it. If the engine is in the car it's awkward but doable with careful drilling the centre of the stud and progressively using bigger drills (new, good quality drill bits). When it's almost to the root diameter of the thread I then fold the stud in using a small, sharp centre punch.
Charles
RE: broken cylinder head stud - Chris KC - 11-11-2017
Hi Ollie,
If it was my only way to get home I'd run it, not if I had a choice. Especially not with any kind of alloy head as you are asking for it to warp.
It troubles me a little that you managed to shear a new stud putting it into the block... I normally just nip them up. They ought to be comfortably able to cope with 20lbft. Was it perhaps a bit too much enthusiasm?
Chris
RE: broken cylinder head stud - AustinWood - 11-11-2017
I guess the old one snapped taking it out.
RE: broken cylinder head stud - James Anderson - 11-11-2017
Hard luck and frustrating dilemma but no brainer with an Alloy head. On a slightly tangential tack what are regarded as 'good quality drill bits' ? I don't seem to have had any lasting that long but that's possibly due to my lack of skill.
RE: broken cylinder head stud - Jeff Taylor - 11-11-2017
For cutting into hard metals, I've always found cobalt drill bits to be the best.
https://www.cromwell.co.uk/shop/cutting-tools/ground-flute-jobbers/set-of-15-hss-cobalt-s-s-drills-1-16inch-1-2inch-x-1-32inch-/p/KEN0268490K
RE: broken cylinder head stud - GK5268 - 11-11-2017
[attachment=1376]
Woodrow Manual gives a very useful tool for drilling out broken head studs, pilot hole first then hole for tapping a new thread, the guides help take out the chance of getting it misaligned. Good luck with this!