Merc 3.0 rocker stud lifted - repair advice ?

[Rake722]

Hi all

further to my stuck valve issue we found that the stud for the rocker in pot 5 was torn upwards by 3/8 inch

we applied 40 ft ib to it and it doesn’t hold.
we will need to extract it and find a way to refix it to its hole.

the engineering shop suggested knurling it and loctite back in place. Loctite permanent thread lock.

wouod this be ok or is there a better fix ?

thanks

 

[Scott Danforth]

take the head to a machine shop and have the pressed in studs pinned

 

[Rake722]

take the head to a machine shop and have the pressed in studs pinned

i didn’t think of driving a pin through them - good call I’ll ask if they can do that but I expect I’ll need to take it to another machine show

would knurling not be an option ?

 

[Scott Danforth]

no, knurling will not hold

and if you dont pin it right, that causes other issues.

which is why I stated, bring the head in. the machine shop may chose to swap you over to thread-in studs

 

[Rake722]

no, knurling will not hold

and if you dont pin it right, that causes other issues.

which is why I stated, bring the head in. the machine shop may chose to swap you over to thread-in studs

im in the UK so that isn’t really an option.
i think screw in must be the way to go on this.
would cutting threads in to the existing stud and helicoil in the head be an option ?

 

[Scott Danforth]

Threaded studs have a hex on them to tighten

To convert to threaded studs, you will need to get a set of threaded studs

 

[Rake722]

I think I’ve just managed to buy the only oversize stud in the United Kingdom

 

[Scott Danforth]

good luck

 

[Rake722]

Thanks Scott, I would have gone for ARP screw in but impossible to get them here. I can only get from the USA and my timeline is too short to allow for that so it’s got to be oversize OEM. I went for 0.03 inch