side water branch stud extraction

[jamesheath]

Hi all,

Moving on to the next "challenge" in our "light" engine overhaul...
As expected, the side water branch studs are heavily corroded. I know that a nity repair plate is (or was?) available to sort this, but on a previous occasion, on a different engine, I got these out, re-tapped the threads to clean them, and fitted stainless studs, which worked perfectly.
On this one, I cannot get them out - I've applied lubricant, heated the surrounding casting etc etc but the stud extractor or mole wrench slips on the remains of the stud - its' just possible tat if I could apply the torque the stud might move..
I have one idea that I'm considering and want to be guided on or talked out of - has anyone ever tried fitting a larger nut flush with the face of the block, then welding the nut to the remnants of the stud?
I suspect that the rest of the stud will then just shear off...
when that fails, has anyone ever had any luck drilling and chipping the remains of the stud out? or drilling then reverse thread tapping the studs to get the remains out?
Or do I stop wasting my time and move on to the repair plate quickly?

Thanks for any guidance or words of caution!

Best,

James

[Nick Lettington]

One thing I keep hoping not to have to try, but still want to have a go at is welding a nut on to the remains of a broken stud...

The heat should help to release the stud.

[Chris KC]

I should have thought a plug weld would work a treat, as long as the sheet/ bar it is welded through will take the torque of untightening.
My worry would be that the flange will break before the 'studlet' comes out. Or that the heat might do a mischief to the cast block.

Can you not simply grind flush and re-drill & tap? If accurately centred (admittedly challenging) you might get lucky and end up with a clean result; failing that drill and tap oversize?

edit: I see I have crossed wires with Robert - looks like we're on the same page though.

[Robert Leigh]

I have tried welding a nut onto the remains, but it didn't work. I have cut the stud short and filed down to be flush with the side of the block, after which it was possible to drill out the remains. Dot punch dead centre and work with gradually increasing size drills until you are up to tapping size. It is a good idea to put a bit of stainless steel behind where you are drilling: it will give you some warning before you drill into the cylinder wall. You may need to finish up at 3/8" thread depending on the state of your block. I use stainless steel studs, loctited in, and make the stud the right length for a dome nut on the outside. Dome nuts (ideally stainless in this situation) with a fibre washer overcome any sealing problems.

[Steve Jones]

I've used M10 stainless bolts (with the legend on the heads turned off!!) for side water branches for many years. I do try to resist any urge to remove them once fitted but on the odd occasion it's proved necessary, I've never found any issues.

Steve

[Zetomagneto]

Steve, why use 10 mm stainless when we can get 3/8 stepped stainless from cherished suppliers?

Robert has best solution, cut off flush, drill and tap, put a hacksaw blade behind the hole to protect the cylinder while drilling. I picked up a  block on one occasion,it had a hole through into the cylinder adjacent to the water stud hole!

[Martin Prior]

I've just done this. I filed the stumps of the studs flush to the block to give a good, flat surface, drilled and re-tapped them and fitted stainless steel studs.

Mark your drill bits for depth - there's not a lot to play with and I have heard of people drilling straight into the cylinder.

Edit: Just realised that I've repeated much of what Robert said above. Sorry!

[Malcolm Parker]

I once had an engine which had a tight spot when turned by hand.  The cylinders were fitted with liners and one of the side water branch studs was pressing into the liner causing the problem.

[Steve Jones]

Steve, why use 10 mm stainless when we can get 3/8 stepped stainless from cherished suppliers?

When I first used 10mm stainless for this job over 30 years ago such things as stepped stainless studs didn't exist. The 10mm worked and given that I'd bought the tap, I've carried on ever since

Steve

[jamesheath]

Thanks all - I think the message is clear - don't waste time welding, get drilling.

Best,

James