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Discussion Starter · #1 ·
Hello All, preparing for the big head gasket job !!, got radiator splash guard off at the weekend and fitted new "jacknuts" plenty silicone grease and s/s bolts fitted now, however noticed that the manifold has 1 stud missing and another broke when I looked at it with the ratchet, with the head off has it got to go on a milling table or can they be removed with drill and screw extractors ? as always all help welcome

TIA Haggag01
 

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drill and screw extractors if you are careful !!
should not be a prob if you have the head off anyway
the recommended way is to have the old stud spark eroded ...


good luck

btw there has been a fair amount of discussion on this before....
 

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It is possible to get them out whilst still in place on the engine block (did it a few months ago).

Basically, just start slow and careful using cobalt drills (or similar as the studs appeared to be very hard and brok a few HSS and "titanium coated" drill bits before I splashed out and bought the cobalt drills). Take care not to go too far in - from my view, this where doing it maually is best, as you can feel when it is just breaking through - as you can pierce the casting (would need to be fairly heavy handed to do more than scratch the surface). Put plenty of freeing oil down the hole made through the centre of the stud and use an "easi-out" or similar tap style stud extractor.

HTH

Pete
 

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I must be lucky then...

Both of my 2.3 T's have the same stud missing, the lower right one of the centre exhaust branch.

The studs have both fallen out and I need to buy a new set and refit.

Luckily 1 complete set will have 2 of this stud.

Andrew.
 

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If I recall rightly, started at 2.5mm (broke through slight misaligment - my fault), went on to 4mm, and finished with 5.5mm - may have gone to 6mm for about first 10mm to give the easi-out a chance to bite properly.

Good luck & be patient,

Pete
 

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Oops, sorry - just what my old man calls it.

yes, it is just a screw extractor. Looks like a spiral fluted tap, but with taper and LH thread so it bites as you try to loosen.

Seen some that get hold of the bit of stud left at the top, but have never been able to use one since whenver I have a broken stud it inevitably snaps too far down.

Cheers,

Pete
 

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Yeah, you can also get "Stud Extractors", which look like spark-plug sockets, but inside they have some roller cams. You fit them over the stud and put a ratchet on them and turn ccw, and the cams tighten and grip the stud and in theory, out it comes!

I have used them successfully, although they can't take massive amounts of torque so a lot of penetrating oil and heat is a good idea.

As you say though, no use if the stud shears flush with what it's in.

I second the caveat: don't snap the easi-out. A friend of mine did that, and it's a very Bad Thing ™.
 

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Originally posted by Sevenman:
[qb]If exhaust manifold studs can cause such problems, would it be an idea to replace them at set intervals before they get the chance to seize? [/qb][/b]
....or replace them with stainless ones and never have to worry about them again
 

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Hi John
Is there no electrolytic results from fitting brass to steel? Broken brass studs would be a one hell of a lot easier to get out even if it did corrode, provided it didn't cause the preferential corrosion of the block threads.
Kev
 

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All I know Kevster is on my old Sierra XR4, someone had replaced about half the nuts (not the studs) with brass ones.

Pretty much all the original steel nuts had welded to steel studs. Some of the came free, some took the studs out with them, some removed the threads from the studs! Usual story...

However, the brass nuts all spun off without a problem, as though they'd just been put on. Only problem is as far as I can tell, that brass being so soft you have to be really carefull not overtighten.

That was an iron head, but it shouldn't make any difference.

I'm still not sure about stainless steel + alloy, having heard a colleague at work who is a yacht owner moaning about this combination, but maybe you need to add salt to get the corrosive effect there!

I did do A-level chemistry once, but that was a long time ago and I can't really remember how this stuff works.

Anyway, I tried to get more brass nuts to complete the Sierra, but nowhere could supply them
 

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Well, this kicked off a good discussion at work (slow day).

Couple of interesting links:

Galvanic series and a link about Saab sacrificial anodes in cooling systems.
Anyone know which models had these?

Anyway, I think electrolytic effects do not come into play here, because there mostly is no electrolyte!

I expect that the best thing to remeber is to use plenty of copperslip or similar
 

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Discussion Starter · #18 ·
I think using brass nuts is a good idea, will go easy with the screw extractors, do not want to have the same probs again, so will be making sure job is done right, we use brass nuts and bolts for our outside lightning conductors and they are never a prob to dismantle, correctly said with it being softer metal will need to watch how hard i crank it up.

Haggag01
 
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