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Tappet Adjusting Screws Snapped

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#1 handrews123


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Posted 21 July 2020 - 05:24 PM



I've recently had the cylinder head off my 1976 1098 Clubman to replace head gasket and studs. 


I have come to adjusting the valve clearances and have found nearly all tappet adjusting screws to be heavily seized and have snapped the screw head whilst trying the undo. 


Obviously I now need to replace those broken and any more that break when adjusting. 


Does anyone have any bright ideas to help to remove/loosen the remaining screws without breaking them? 


To replace these adjusting screws, I assume I need to remove the rocker shaft as the ball won't come through. What will happen where I have torqued the head down? Will I need to replace head gasket/studs? 


Any help or ideas would be much appreciated!

#2 nicklouse


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Posted 21 July 2020 - 06:32 PM

Depends on where they have broken.


as you say you were adjusting them I would guess the ear of the adjuster screw has sheered off.


remove nut and unscrew.


as they are normally covered in oil they should come out fairly easily.  The damage8 have seen is through too much force being applied to the lock nut.


if they will not un screw then the whole lot needs to come off.


if head is dry. Not been filled with oil or water you should be fine leaving as is.

Edited by nicklouse, 21 July 2020 - 06:32 PM.

#3 Moke Spider

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Posted 21 July 2020 - 06:55 PM

As Nick says, you can try get them out the bottom of the Rockers while fitted. If you turn the engine over as you get to those that are on the Cam Lobe it will give you some more clearance.


As you don't yet know how extensive the damage is here to the Rockers, (they may have damaged threads), I'd probably be more inclined to find another set of rockers as there does seem to be plenty about. You could recondition them (replace the Shaft and have the Tips re-faced) before fitting.


You can often get away with Removing the Rockers and not damaging the Gasket, however, to avoid the Gasket becoming over crushed at the front, back all cylinder head nuts off (not all the way, leave some tension on the fronts) this should help.

#4 handrews123


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Posted 21 July 2020 - 08:26 PM

Thank you for replies.


Nick is right in that the ear of the adjusting screw has snapped after applying, probably, too much force. 


Will see if I can remove and replace the screws in situ like suggested but as long as I'm okay to keep head gasket and studs, taking it off isn't too much hassle. 


Am I right in thinking part number AEG167, is the correct replacement as there are various options in Mini Spares.  https://www.minispar...px|Back to shop

#5 croc7


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Posted 22 July 2020 - 04:58 AM

Which begs the question, what is the correct torque value on the valve adjustment nuts? Just “nip” them up ain’t exactly precise. I don’t want to over torque them nor do I want them loose enough to lose the setting.

Edited by croc7, 22 July 2020 - 06:52 PM.

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