ReThreading studs

[g4pyd]

Hi,
I have pulled a cylinder head stud on my 32 SV engine,The thread has stripped in the block, What would the best way of refixing stud I have made a new stud, the only thing I can think of is the" helicoil system".
I wonder if this will be OK
Colin

[ian judd]

I don't know if these can still be got, but I once used something called a 'stepped stud'. It had a larger thread at the bottom where it went into the block.

Ian

[Ian Grace]

Colin,

You could also have it Helicoiled. The Helicoil process (just Google 'Helicoil') involves threading the hole oversize and inserting a thing looking like a spring that has the oversize thread on the outside, and the stadard thread required on the inside. I have never personally used them, so I'm not absolutely certain it would be strong enough for a head stud. I suspect I'd rather go Ian Judd's way and have a special stepped stud made. I doubt if anyone makes them for the SV engine, but you might call Mike Dowley on 019239/210458 who has OHC Minor/M Type cylinder head studs. He might just offer stepped studs for these engines. They will be much too long for your SV application but could easily be cut down and re-threaded for the head nut. While you have him on the phone, order a set of high tensile head nuts - (remembering that there are more on the SV head than the OHC head!).

[g4pyd]

THANKS IAN's,
I have a lathe and may make stepped studs but would prefare helicoil system if it would hold with locktight,
it would save a lot of time (mabe(

Colin

[Trevor Wilkinson]

Helicoil or other makes of the same idea work perfectly and it doesn't take long to do, you get the "coils" a coil inserter and special tap, just a matter of drilling the block out to size and then tapping the hole and inserting the coil. You need to make sure that it all remains "square", I made up a simple jig. Whole job is done in minutes and is stronger than original.
I used "RECOIL"

[g4pyd]

Thanks Trevor, I will use helicoil as i already have a set, I will let the thread know how well it worked????
if it does not work then it has to be stepped studs..
regards Colin

[g4pyd]

Helicoil works just fine, I replaced two studs and I am sure they are stronger than new,and used new nuts from Ian Harris 5/16 bsf x 7/16 high,fantastic and a big thanks to every one who helped