1) Further to recent missives concerning my 650SS, I am replacing the three studs in the cylinder head - or at least, I am trying to. I have removed the one at the back of the head, but the other two, one under each exhaust port, are proving difficult. I have tried putting two nuts on each stud and tightening them together to form a lock nut, then tried to spanner the studs out without success. I have tried using Mole grips, both on the head at ambient temperature, and with local heat applied, all without success. The studs have several graunch marks on them now! Has anybody got any more ideas, especially if you live in the Bristol area?
2) I have siamese pipes on my machine, which, with some difficulty, and the judicious use of some light 'brute force', I have managed to seperate to make it easier to fit back to the head later. Has anyone found a method of reassembly which will allow easier seperation at some later stage? Would Copperslip grease help. Any suggestions would be gratefully received.
Heat the head in the oven first and then get an industrial oxy/aceteline torch on the alloy around each stud separately and using the double-nut method they usually come out. If they have been assembled with a thread lock adhesive the extra heat should break the resin and heating the head up evenly beforehand should stop the extra heat dissipating too quickly. The thread into the head is BSF if my memory serves me correctly and is easily stripped so if all else fails just tighten the nut against a spacer and strip it out. Then of course you will need to make oversize stepped studs or fit helicoils into the blind holes. Persevere and you will do it. Regards, Howard
I've used one but don't have one - it is like a large socket with 3 knurled wheels inside on eccentric pins. Works like a sprag clutch in that the more you tighten, the more it grips. Worked on a stripped thread stud for me. With one, you should be able to get more torque on it than using moles.
I agree with Howard in that heat is your friend. Heat the head in the oven first, but limit the heat to 180°/gas mark 6 or the alloy properties can change.
Another 'trick' that can help is the freezer spray that plumbers use. With the head oven hot, spray the stud with freezer spray and immediately try and turn it.
Good luck and I hope you get there.
I use standard roller type stud extractors for removing and fitting studs. They are similar in appearance to an extended socket and the internals have a cam action and they do not damage the stud. They are sold in sets covering the most common stud sizes. Care needs to be taken when removing stubborn smaller diameter studs as the grip is so effective one can easily shear the stud. However a combination heat where practical can help too. Copper ease is always useful and also helps to reduce the galling of threads in particular on stainless steel.
If stud shear, is it practical to use a left hand twist drill. In a rigid bench press drill or preferably a stiff machine?
Hi David , all of the advice will work with care, as one member has indicated with the head held firmly and the extra torque available with a stud extractor you can quite easily shear the stud. On no account should you use an oxygen torch unless you are very very conversant with one of these tools. I find that the oven method works well , but it helps if each of the studs is given a sharp vertical wack with a hammer..Before attempting to turn the stud, just make sure you have something between the end of the stud and the hammer, a piece of aluminium or brass, although it seems your studs might be scrap anyway.
assuming you are replacing studs then damage to threads will not matter, hold one in a vice and turn the head. you should get half a turn before other stud fouls vice. if it still slips in vice, file a flat on the stud and try again.
got to ask, why do you want them out, if the threads are good leave them in.
The reason for the need to change is that the threads on the other end of the studs are looking worse for wear, so I thought I'd change them while I've got the head off, to save possibly having to do it again later.
I'd be tempted to just run a die down them. They're probably made of better material than a lot of the after market stuff that's around.
hello, none of you has mentioned a stud removal tool which I would use after being in the oven for a half-hour the thread into the head is Whitworth 5/16 for the front 3 and 3/8 at the rear stud the fine threads are cycle 26tpi and not BSF the other way is to file a flat on either side of the stud so you can get a spanner to fit and as low as possible and try the oven method first someone as used Loctite on the threads, hope you win in the end try not to snap the studs if all fails you can away send it to me only cost you the postage As I have the skills and a well tooled up workshop yours anna j
Quote "hello, none of you has mentioned a stud removal tool which I would use after being in the oven for a half-hour "
Have you read any of the replies above? Both George Arber and I mentioned stud removers, and heat too.
Maybe some of the later engines had 5/16" studs at the front (don't know about the back), but mine are all 3/8", BSF into the head, with BSCY through the barrels.Looks like there is some kind of gunge on the studs, perhaps it's Loctite or similar.
Have run a die down the threads, they still look a little 'iffy'.
Hello well my 1960 Norton Manxman 650 As 3 front studs that are 5/16 and I can send you photos of them if you like
Anna - David is talking about the three studs into the cylinder head not the studs into barrel. If yours are indeed 5/16 inch please can we have an image or two ? Regards, Howard
Pretty sure my 1960 99 head studs are 5/16" ,A 60 Manxman is unlikely to be different.
Radco recommends drilling studs to remove them if broken. Accurate centre punch and slowly increase drill sizes. For sound studs he only recommends the twin nut method. But, and perhaps this might be relevant, he says to odd Loctite Stud-lock. So there's a problem for future removal. If so Loctite is weakened by heat. Bit it all sounds a lot of work if the damage is cosmetic. If the twin nuts will not remove it, surely it must able to safely take a nut for service use?
I have used a knurled socket stud tool as described by George, not expensive . I also impact the stud to jar the threads first and use a shock tactic rather than a steady pull. I have also drilled out stud remains and peeled out the thread remnants . If all goes wrong a Re-thread insert will save the day.
Just in case there are any readers of this Technical Forum new to Norton twins and wanting facts not fairy stories here are a couple of images of the offending studs. As you can see they are 3/8 inch BSF threads into the head and 3/8 inch BSC for the nuts. The images also show the rear nut with double hex (one reduced to allow access whilst fitted) and one of the front nuts. Get some heat on them if they have to be removed. Cheers Howard
There are 2 front 5/16 studs ,but they are Barrel to head.
If you'd read my posting on 27th March you would have seen that David was referring to the three studs into the head not the barrel........The lesson is if you can't be correct in what you write then don't write at all. I thought that you were being chivalrous because Ms Dixon often gets a misconception of the facts and writes rubbish. She is very capable of standing her own corner. Stay safe, Howard.
I don't read acidic postings if I can help it. Anna has plenty of Helpful info , just has some dyslexic issues . If members won't post because they may make an error the site will die like many others.
This tip came from a friend who was a tool and die maker:
Instead of locking two nuts together, which can stretch the threads, get a nut of the correct size and thread, cut a slot in it across one of the flats with a hacksaw. Now screw this nut onto the stud and grip it with a pair of vice grips (mole grips) either side of the slot. This way you can grip the stud really tightly. Of course, the above comments regarding heat application are valid and will help the process.