Skip to main content
000000 000003 000006 000009 000012 000015 000018 000021 000024 000027 000030 000033 000036 000039 000042 000045 000048 000051 000054 000057 000060 000063 000066 000069 000072 000075 000078 000081 000084 000087 000090 000093 000096 000099 000102 000105 000108 000111 000114 000117 000120 000123 000126 000129 000132 000135 000138 000141 000144 000147 000150 000153 000156 000159 000162 000165 000168 000171 000174 000177 000180 000183 000186 000189 000192 000195 000198 000201 000204 000207 000210 000213 000216 000219 000222 000225 000228 000231 000234 000237 000240 000243 000246 000249 000252 000255 000258 000261 000264 000267 000270 000273 000276 000279 000282 000285 000288 000291 000294 000297 000300 000303 000306 000309 000312 000318 000321 000324 000327 000330 000333 000336 000339 000342 000345 000348 000351 000354 000357 000360 000363 000366 000369 000372 000375 000378 000381 000384 000387 000390 000393 000396 000399 000402 000405 000408 000411 000414 000417 000420 000423 000426 000429 000432 000435 000438 000441 000444 000447 000450 000453 000456 000459 000462 000465 000468 000471 000474 000477 000480 000483 000486 000489 000492 000495 000498 000501 000504 000507 000510 000513 000516 000519 000522 000525 000528 000531 000534 000537 000540 000543 000546 000549 000552 000555 000558 000561 000564 000567 000570 000573 000576 000579 000582 000585 000588 000591 000594 000597 000600 000603 000606 000609 000612 000615 000618 000621 000624 000627 000630 000633 000636 000639 000642 000645 000648 000651 000654 000657 000660 000663 000666 000669 000672 000675 000678 000681 000684 000687 000690 000693 000696 000699 000702 000705 000708 000711 000714 000717 000720 000723 000726 000729 000732 000735 000738 000741 000744 000747 000750 000753 000756 000759 000762 000765 000768 000771 000774 000777 000780 000783 000786 000789 000792 000795 000798 000801 000804 000807 000810 000813 000816 000819 000822 000825 000828 000831 000834 000837 000840 000843 000846 000849 000852 000855 000858 000861 000864 000867 000870 000873 000876 000879 000882
English French German Italian Spanish

Cylinder head studs replacement on Dominator series + exhaust pipes

Forums

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.

Thanks,

David Francis

Permalink

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   

Permalink

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. 

George 

Permalink

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.

George

 

 

Permalink

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.

Permalink

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.

regards Martin

In reply to by martin_freeman

Permalink

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.

Regards,

David Francis

Permalink

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.

Permalink

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

Permalink

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.

 

 

Permalink

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

Permalink

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?

Permalink

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.  

Permalink

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

Permalink

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.      

Permalink

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.

Permalink

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.

 

Norton Owners Club Website by White-Hot Design

Privacy Policy