Cylinder head/barrel stud pulling out of block

[Steve Boar]

Hi, need help and or advice
The bottom right (forward) head/barrel stud is pulling out of the block. The other three will accept a torque for adjusting the valve gaps (tappets), but this stud will not torque up and has visibly extended away from the block.
Are the studs simply tapped into the block, or were they helicoiled at the factory?
And any advice on how to get the stud out of the block?
regards
Steve Boar

 

[KMD]

Hi Steve, there are a number of people on here who will have that knowledge, but you (they) may benefit from knowing the bike’s make, model, age, mileage etc and any modifications such as an 800 engine modded to 1’000 and such like.

 

[DrFarkoff]

Hi, need help and or advice
The bottom right (forward) head/barrel stud is pulling out of the block. The other three will accept a torque for adjusting the valve gaps (tappets), but this stud will not torque up and has visibly extended away from the block.
Are the studs simply tapped into the block, or were they helicoiled at the factory?
And any advice on how to get the stud out of the block?
regards
Steve Boar

Drilled and threaded into the block at the factory

There is a jig set up that you can buy from Cycle worx USA or Hire from BMW club (I think)

the usual is to drill and rethread Some people use timeserts and clearance the oil feed (top Bolts have a hole to feed oil pressure to the rockers which drains back down the Pushrod tubes)

but I just make sure that I have drilled square and deep and that the stud is threaded in a decent amount so that I only have about 3 mm left outside of the rocker pillar nut when fitted

Also Note forcing the stud deeper is a "no-no"!! If you want a depth measurement I have a spare block I can take that for you

 

[mikeyboy]

I just drill out and helicoil,
Ideally you need a x2 insert(20mm)
The stud once inserted should not protrude into the crank case(flush on inside)
In the case of an 80 or 100 the stud should protrude 254mm.
HTH
Obviously with the upper studs a bit more care/ work is needed to ensure the rocker oil feed galleries are not blocked

 

[mikeyboy]

In regard to getting the stud out of the crankcase,if the thread has already failed,just keep winding the nut on till it pulls out completely.
Add some washers if necessary

 

[Steve Boar]

Hi Steve, there are a number of people on here who will have that knowledge, but you (they) may benefit from knowing the bike’s make, model, age, mileage etc and any modifications such as an 800 engine modded to 1’000 and such like.

Thanks for the info. I have a 1991 R100RS Mono, with no engine mods.

 

[Steve Boar]

Drilled and threaded into the block at the factory

There is a jig set up that you can buy from Cycle worx USA or Hire from BMW club (I think)

the usual is to drill and rethread Some people use timeserts and clearance the oil feed (top Bolts have a hole to feed oil pressure to the rockers which drains back down the Pushrod tubes)

but I just make sure that I have drilled square and deep and that the stud is threaded in a decent amount so that I only have about 3 mm left outside of the rocker pillar nut when fitted

Also Note forcing the stud deeper is a "no-no"!! If you want a depth measurement I have a spare block I can take that for you

Hi, thanks for the info. I am in the UK, so US tools are going to be difficult. But I will take all of your advice onboard. I have heard Timeserts are good. Thanks again
1991 R100RS Mono

 

[Steve Boar]

In regard to getting the stud out of the crankcase,if the thread has already failed,just keep winding the nut on till it pulls out completely.
Add some washers if necessary

Hi, thanks that is the exact info I was after. I was thinking that was the way to go, just wanted reassurance.
1991 R100RS Mono

 

[Steve Boar]

I just drill out and helicoil,
Ideally you need a x2 insert(20mm)
The stud once inserted should not protrude into the crank case(flush on inside)
In the case of an 80 or 100 the stud should protrude 254mm.
HTH
Obviously with the upper studs a bit more care/ work is needed to ensure the rocker oil feed galleries are not blocked

1991 R100RS Mono
Hi thanks for the info. Much appreciated

 

[DrFarkoff]

And any advice on how to get the stud out of the block?

Just put two nuts on it and lock them together and unwind it

 

[mikeyboy]

Just put two nuts on it and lock them together and unwind it

I’d made the assumption it wouldn’t screw out

 

[DrFarkoff]

I’d made the assumption it wouldn’t screw out

Who knows @mikeyboy Sure we both know we never get the full story until we start stripping/fixing them !

#NoFoul

 

[Mad Hatter]

Take a look at this

Cylinder Stud Repair