Triumph Stag Heads fail Part 2. Does the tool i made work?

[@garysweetland32]

Love your idea for drilling the stud, that should keep it nice and square. When cutting hard materials you need a lot of constant pressure (more pressure than a hand battery drill) and a SLOW STEADY speed. Ideally a pillar or radial arm drill. Stainless will cut with normal HSS drills, but the moment you let it rub, it work hardens. Hence the need for a lot of pressure. We managed to drill the studs out of a V12 Vintage Rolls Royce with a small pillar drill that we bolted to the back of the head. Not an easy option with a Stag, but you might get it under a floor standing pillar (or radial armed) drill.

[@bobfrankish8883]

I feel your pain! I can't think they are stainless. Stainless is notorious for thread galling under torque, so would not really be chosen for a head stud. It is interesting that they are hardened to that degree as you could imagine them being too brittle for their purpose. Personally, I would give an induction heater a try. The problem with applying localised heat via a flame is that it only heats up the very end of the stud. The aluminium head is a perfect heat sink so the lower end of the stud will be stone cold. Because induction heaters work electro-magnetically, I don't know for certain, but I can imagine them heating up much more of the stud. Might be worth a go.

[@YorkshireClassicCarsltd]

Stainless studs are definitely available. These are magnetic, so depending on the stainless used they may have just heat cycled to this hardness, but I'm no metallurgist so I'm just guessing really

[@bobfrankish8883]

@@YorkshireClassicCarsltd Ok. I'm no professional or expert, just because I've never come across them doesn't mean they don't exist. It' funny, I've just recently tried to harden a mild steel bolt by heating and quenching and it didn't make a shite of difference! All I know is, I had some seized bolts on a project, I tried everything at my disposal, bearing in mind the hottest flame I have is a propane torch, no joy. My son borrowed an induction heater from where he works and they came out.

[@WOFFY-qc9te]

Defiantly not stainless it has been years since I battle a Stag head but when I did they were always corroded, same with the Herald which I actually had running with no head bolts. . Speak to a machine tool maker he can knock up a hollow reamer alternatively remove the cams and any other alloy and dump it is some hot caustic for a week and devolve the heads. . The induction heating is a good idea especially if you are heat cycling with some hammer action to shock the stud.

[@KJs581]

@@WOFFY-qc9te Agreed, they are high tensile, not stainless. While there may be stainless that approaches high tensile, I have never seen it used for high tensile applications. That is my limited experience, so not to say it hasn't. But my two recent bike rebuilds, (replacing every nut/bolt or checking every thread) all the "tin ware" held by stainless, wheras all load bearing = high tensile. The Navy (my Navy, RAN) loved stainless, but there is stainless and stainless. For random upper deck fittings - no worries. But for high tensile applications - too brittle. We were constantly resisting them using stainless on heavy items because engineers who should know better kept pushing us to. We used to have a two ton radar aerial, LWO2. Had 9 of them. The carrier got a new aerial, uprated reflector. They used stainless bolts. They went to sea, and second day - it just fell off, straight over the side. Amazing no one hurt. Everyone argued over whether was the SS bolts fault, or not torqued up properly. The old LWO antenna went back on - old high tensile bolts in - never again a problem. Never had problems with 9 aerials with high tensile (and I have had half of them on and off by crane/overseen it), but the one with stainless bolts "fell off", so.................. I am naturally wary. Maybe that's just me.

[@WOFFY-qc9te]

@@KJs581 Definitely not stainless, Stag heads are problematic as were the Herald. Corrosion which is easily prevented on assembly with some copper slip but BL didn't care about that or washing out the casting sand. The best thing you could do before starting your new BL was wash the engine through with kerosene. I found the BL head tightening sequence upset the valve clearance after some experimenting I found that backing off the diagonal bolts a bit then taking them up was best. I the head was being pulled into the centre and this would show up on a dial gauge on the cam journals and was probably why the gaskets failed between centre cylinders. That and the porting out of the bypass water jacket at the rear meant I never had a head cause me problems. Tip clean your bolts to bear steel and drop them in copper sulphate for ten minuets this give them a light plating. Marine corrosion and radar, you are not alone in have some well meaning individual incorrectly securing radar to a Procter mast. Fair winds.

[@Fintoman]

The hole (tube) cutter is worth a try. You might be able to extend the cutter by welding a piece of tube into its body to lengthen it to the desired length you need. Of course, this is all time and money. I wouldn't throw the towel in just yet until you've at least explored the idea. Good luck.

[@KJs581]

Hey mate, I said same above BEFORE I read your post here. I have left my comment above as a bit of extra info. Cheers.

[@aprildangelo7457]

When running our garage we used to do loads of Stags, Sprints heads, had loads with the heads stuck we used thin blades to get a gap between block and head, then with hardwood wedges hit into gap so a hacksaw blade could slip through and slow progress cut the studs, the threaded bit came out of the block easy enough and press studs out of the head, later on we ended up converting Stags to 2.5 straight six motors, they were faster and ultra reliable. good luck.

[@KJs581]

They are high tensile, so they are very hard. If it were me, I would have ground the screwdriver slot off/ground top flat to let the drill have a better time, but even then, drilling them out is a big ask. Some great minds in these comments, many smarter than me. :-) As said below, wooden wedges are often a good tool, as can apply a lot of force without distortion/they will split before damage. As I said in the other thread, my first one I did, most came out, but three took a week of fiddling. I used hypodermic syringes and injected penetrene into the creases around the studs - eventually came out with two nuts locked against each other. After that, mine with socket heads and never seize on the shafts are a breeze to get out. But the stubborn ones, one engine had sat for 15 years, and I used two hydraulic jacks to get them moving, but I mainly wanted the block. After levering those heads off, the last couple I welded some nuts on, then they came undone. Of course, you can also weld nuts onto the studs with heads on, but on a couple I did that - they snapped, so had to lever the block off. What is worth trying (I know this is a bit "suck eggs) is if you can move the engine (is out of the car) so that the face where the stud is horizontal, put penetrene on that face around the stud and leave it for a week (if you have the time). Making a well even better, get some good quality silicone, clean the face, seal the face with a ring/ bead of silicone (I have seen plasticene used, but it leaks) and then fill it with penetrene or Kroil or whatever penetrating stuff you like. If you have to top it up, that's good, as it is seeping in. I have also seen people use hole saws, it is a hassle but an option. I had a go at it on mine and it did work, but those heads were corroded beyond use anyway, so more a "see what if" for me. While a conventional hole saw tooth set/kerf width may cut away too much of the head, there are those cheap "diamond dust" ones all over ebay that are very thin, far thinner than toothed ones. You'll go through a few, but they are cheap. Of course, have to be careful, as could ruin head, but there is a lot of "meat" around those studs, and the stud centres it/keeps it true, and not worried about location, as the lower bolts will do that, and you won't be drilling all of them. That will only get you so far, but you could either weld a tube onto it to go further, or just use the groove you have started as a well for penetrene. Of course, very slow, have to stop every so often/blow out with air to remove dust/swarf. But another option. The diamond fragment ones are designed mainly for masonry, but they will go through ally, just will clog, so have to clear every so often. Not perfect, but just a few more "strings for your bow." I was in the Navy for 40 years, and when our gear broke half a world away from base/stores, we often had to "make everything/imporvise" until we got home or got bits, so often there IS more than one way to skin a cat................ (or behead a Stag). 🙂 I used the lathe on the ships I was on (and in the workshop ashore) more than anyone else on board usually....................... but half that (in the shore WS, admittedly) was during lunch time to make/fix car parts. 🙂

[@WOFFY-qc9te]

Definitely not stainless steel. Get a toolmaker / machinist to use a hollow end mill over the bolt, any good machine shop should have that off. I never had a problem with Stag head once I changed the tightening pattern, After nipping up the vertical bolts slightly back off the diagonal then tighten again and repeat. The reason is the diagonal bolts bend the centre of the head below the cam under tension this is seen on a dial gauge and is why your shims measure differently after assembly ? and is probably why they blow gaskets so easily. Also open up the water bypass passage at the rear. Never had a problem head. Drop clean head bolts into some copper sulphate for a few minutes will give them a thin plating of copper then use some copper slip. I to have had a Radar part company from a Proctor mast due to some incorrect fittings. Fair Winds

[@docjohn5986]

Hmmm, if they are magnetic and very hard they may be 400 series martensitic stainless steel, something like 410; goodness knows why anyone would use them though. But they should still be able to be drilled with a cobalt drill at low speed with cutting fluid... I'm sure that you've thought of everything, my thoughts would be EDM or spark machining the studs out although that could be expensive. If a carbide or cobalt drill won't touch the studs then I can't see a core drill touching the threads, so you'd be into drilling the aluminium. Then, to keep the location you could make insert sleeves for each hole in the head, but you are adding work and cost. For the studs that haven't broken how about welding a big nut on the end and using an impact wrench? I've done that on broken flathead Ford V8 studs as I'm sure you have in other cases. Good luck!

[@Peter-b7t1k]

I remember when these first came out and the heads were off nearly every one we sold, nearly every engine had to be rebuilt after overheating, some heads were a challenge, I remember we had a tool and I’m certain it was a BL factory tool for stud removal. Basically a variation of the 2 nuts locked together. It had an internally threaded inverted top hat shape that screwed down the stud thread till it contacted the head then another long internal threaded nut that went inside the the outer nut and you locked the 2 together then unscrewed the stud on the bottom top hat shaped nut

[@racertwo]

Have both valves closed on the cylinder, make an adaptor to screw into the plug hole that will allow you to pump in oil and hydraulic the head up, once the gasket goes you can use taper wedges to lift further, skim heads after removal.

[@anthonyrawsthorne656]

A bit of Galvanic corrosion? (Reason why Stainless bolt kits aren't sometimes upgrades!) Have you access to a floor pillar drill? Get some kore weight behind it?

[@PaulRobinson-u7h]

I’ve seen a few videos on KZbin where spark erosion is used to remove studs as a last resort. If you search for Bolt removal spark erosion machine, you should find one. Not sure if anyone does this in the uk, or how much it would cost, but it would be a shame to destroy the engine trying other methods. If spark erosion was used, not sure how much of the stud you would need to remove or how you would get the remaining bits out of the block but just wanted to throw this idea out there.

[@TheGranty1739]

Call Greno garage at Grenoside Sheffield they have a spark eroder that will shift them.

[@Paul-dz6fs]

I think what you are dealing with are mild steel studs that have case hardened due to the overheating and possibly a previous overheat, maybe at some stage in the past where the fans have given out. Based on my time as BL trained and then a BL specialist for a good number of years, I would say your main issue isn't so much the studs in effect welded to the head, but more the solidified muck around the studs. I assume you have tried welding the nut to the stud and in effect turning them into a bolt ? .. this is one way we used to get round that stupid slotted stud that chewed out long before any studs would ever shift. The trick was to not try and force the stud out by brute force and ignorance, but by putting an impact socket on the newly made bolt and just keep trying to shock it loose with a hammer, almost like an impact wrench idea. Once the gunk shifted, they would then give (but still bloody tight). If all else fails, then the holesaw idea is probably your best option, with sleeving the new studs on reassembly. This will hopefully save the heads. I hope this helps my friend .. I feel your pain.

[@stevesalvage1089]

I think basically its the quality of the tools these dsys , the tube saw method was old sykes tool kit used in the aircraft industry , the other method was a large hand drill mounted in a adjustable jig bolted to the head , it had a bench lever mechanism to apply pressure, its a fair amount of even pressure like in a lathe. o well. , there are other alternatives. Witch you. Mention i hope you can sort it thanks for the mention ,

[@glennroke9480]

It's generally not a good idea to use aluminum and stainless steel together because they can corrode each other, especially in corrosive environments or when large surface areas are in contact:   Galvanic corrosion: When stainless steel and aluminum are combined in a galvanic cell, the stainless steel can cause the aluminum to corrode and fail quickly.

[@johnmurray3324]

Have you tried boiling them a old guy showed Me a d fellow apprentices how boiling a few times can free studs hot and cold it works

[@neilwharton720]

I wouldn’t think they are stainless you can drill that reasonably easily with cobalt drills must be hardened steel of some sort 👍

[@YorkshireClassicCarsltd]

It depends on what grade of stainless they have used, assuming they are. I once picked up some old catering grade stainless off cuts to make exhaust hangers from, nothing would drill it, and bending it was near impossible!

[@doloresmyatt9737]

SAAB made a tool to take off tr7 heads etc and the stag and tr7 owners club hire them out. other people have made their version which are used on you tube vids

[@YorkshireClassicCarsltd]

I assume that will be the same as my tool you use a jack with, bit it won't entertain these

[@davidstaines5440]

How about fitting a Toyota 1uz 4litre v8. Would be a fantastic upgrade.

[@doloresmyatt9737]

@@YorkshireClassicCarsltd no a jack is not needed and the tool will not damage the engine. if you email the clubs that you the triumph engine in their cars they might let you hire it

[@doloresmyatt9737]

ps this tool uses even pressure to lift the head off the studs

[@WOFFY-qc9te]

@@davidstaines5440 Now your talking I love the 1UZFE my LS moved like a stabbed rat on LPG. However the Stag engine is a great beast when set up properly just don't tighten the heads the way BL say also use the shims for the SAAB as the are in 1 thou.

[@Bristolcentaurus]

you need a carbide drill carbide will cut hard steel like butter but you will need a mill as carbide is brittle and will not bend at all - ie hand held wont work as you will snap the drill - if you are going down that road a carbide bottom cutting end mill will do the job - an EDM will also do the job - your machinist just does not wont to know its a lot of stuffing around