Roger K

Thanks all, I'll keep it simple.

Just popped the back off my diff to drill for a drain plug. Whilst I have it off, is it worth converting to a more sophisticated breather design? Any recommendations? Thanks, Roger

I always used to use the block of wood. Pick a beefy looking part of the block to wedge it in, and use the longest extension bar you can - or you could even risk a bit of scaffolding pole over the end of a big one, but take care - bursting sockets are not unknown. An air impact driver is the best option but I'm going to guess you don't have one. If you do, be doubly certain that you are using it with an impact socket. A burst socket on one of these does much more damage.

Not done any tin bashing on my GT6 yet, but have just finished a full body restoration of the XK140. Most of that was 20ga, which in Jaguar's case was 0.9mm. Not that easy to source but do-able. 1mm is fine, and for heavier-duty stuff 1.5mm is good. If you're doing a lot of butt-welding it's best to get the same gauge, otherwise it's very easy to unintentionally 'add lightness'.

Don't worry, I 've had several cars that use the bobbin arrangement so am quite familiar with them. I chose the Phoenix sport rear box as I feel the standard box is a great lump of metal, with quite restrictive tailpipes given the diameter of the main pipework. It's also very quiet... that said, I'm trying to keep the car looking as stock as reasonably possible apart from some wider wheels. For that reason I've chosen the Phoenix box over the wheelbarrow handles, which I had on my first GT6 back in the day. I was hoping not to have to drill the boot floor, which isn't braced for a bracket anyway - but as the sport transverse box doesn't go near the midline mounting bracket on the rear valance forward face I guess I'll have to do something extra. I doubt the right hand mounting bracket at the tailpipes and the diff mounting alone will keep it hanging straight. The exhaust, that is.

I'd appreciate some advice on fitting a sports exhaust rear box. I've bought this from Rimmers, along with a fitting kit - but there's no diagram or clues of any sort as to how the fitting kit should go. My old standard box (twin exit on the RHS) had two mounting brackets to align with the factory brackets welded to the boot floor and rear valance. The new Phoenix (I think it is) box, which is similar but smaller, has only one mounting bracket on the far right hand side, above the tailpipes. How do I mount the other side? Not sure a clamp on the tube with a rubber strap will reach the factory mounting bracket on the car. Or is this one not used with the sports exhaust? Worried the weight will let it hang at an angle rather than level, if there's only one strap. Also, is the rubber grommet in the kit for the diff mount, or somewhere else? Thanks

Thanks both - hoped that would be the case. Roger

What's the best way? The diff is out of the car, so will be easier to drill, but that means the swarf will land inside on the working parts rather than collect around the hole to be flushed out. Can I pull the output shafts easily, to enable me to remove the rear casing to drill and tap it? Or will that upset any settings/seals etc.? Thanks

Does anyone know if this AJUSA head gasket will fit a late MKIII GT6 2000 engine? I'm planning a head job over the winter and do not wish to risk a Payen. Is there any way of finding out the part number? Don't have FB myself. Or maybe just ask Chris Witor what's best? Edit - that said, just looked at Chris Witor's website and the photo of a 2000 gasket appears to be a Ajusa, going by the packaging next to it.

Perfect, thanks all. That Bullfire link is going to be very useful, thanks Ed!

Thanks Rob, that is what I meant. I've checked, and the curved appearance I mentioned is actually the factory seam sealer, still covered in the original paint.

Thanks, that's helpful. Does the inner sill come down onto the floor vertically, with an inward facing 90˚ flange on top of the floor?

I'd be very grateful if someone could post a through the floor and sills of a GT6 MkIII. I'm trying to work out how the various panels attach. On the inside of the car, the floor wells seem to curve upwards into the inner sill - is this right? Or does the floor flange turn down to meet the inner sill and outer sill in a triple layer? Thanks Roger

Ha - when my only daughter was born in ‘90, I visited again the next day and came out of the Rosie (Cambridge) to find my GT6 had been broken into. They got a few cassettes (yes, that long ago), but nothing else. The real pain was that they’d smashed a rear quarterlight thinking they could reach the lock and, when they couldn’t, smashed the side window as well. Took me ages to find the Sundym glass for both.

I wish - oh well, back to a cold workshop and scraping old underseal off the underside, lovely

Pretty sure that's the one I have, I think. DRO are good, I buy a lot from them. M&W used to be a top-notch British maker, but I doubt they're made here any more. There's a lot of good quality older kit on ebay, but any kind of mic, even the top quality ones, would need a calibration check if they're getting long in the tooth.

Depending on what size your mic is, you can measure the crank journals and compare with the factory figure, assuming it's not had a regrind. You can't measure bore with it. As Iain has said, you need an at least half-decent bore mic for that, so if you're only doing the one engine it's hard to justify the expense. If you're taking it to a machine shop, you would rely on their measurements anyway so there's not much point in buying your own.

Perfectly valid response. As I have said, my suggestions reflect my own personal approach only, although I might take issue with 'little regard to cost'! I cost these things out very carefully.

Depends how far you want to go. How old is the timing gear? What condition is it in? Flywheel - does it need a skim? Ring gear OK (they usually are)? Valve train (rockers, shaft etc.) - I doubt this will come with the reconditioned head? Oil pump drive (if it's not part of the pump)? It's years since I worked on a Triumph six-pot (correction - decades), but I do recall lots of warning lights around the crankshaft thrust washers. Before you spend any money on anything, I would take the old crank bearings with you to the machine shop, if you take that route, and ask them to check the crank end float. You'll need all the bearings so they can assemble the crank to take the measurement. Given what you know about the engine it shouldn't be a problem, but it's a simple check. If the thrust bearings have worn excessively the block might be damaged and that will cost.

Over the years, I have learnt the hard way (but not on Triumphs) that renewing or upgrading one element of an engine will often pass a little extra strain on to something else down the line. On a worn engine, even doing a decent head job can increase the strain on the bottom end, leading to increased wear. The phrase 'parts that wear together, play together' comes to mind.

I would just say that my post is what I would consider best practice. As others have said, it's always possible that you can just clean up and carefully reassemble and it'll go for years - it all depends on what you want to end up with, how much you're prepared to pay and how much risk you are prepared to take! Nothing wrong with screw micrometers - that's what mine are. The old Moore & Wright ones with the ratchet screw are nice and reliable so long as they're calibrated. You could try measuring the crank main and big end journals and see what you come up with. Measure each one at least twice at 90°. And yes, as Clive has said - putting it together will be what comes next! At the very least you'll need a piston ring compressor, and if you've never fitted rings before you might consider buying some extra rings, shouldn't cost much. Piston ring pliers are nice and make the job a bit easier, but the sky's the limt when it comes to buying tools. That's why I never let my wife see me getting into the Snapon van...

It helps if you can get recommendations from locals for a decent machine shop. I measure the bores myself with a bore mic, the crank journals with a mic and (before disassembly) the crank end-float with a dial gauge, but would still take the block, crank and pistons/rods along to the shop and ask them to assess it and advise on the best course of action. They will recommend either a rebore to the first oversize if the bores are showing wear but no damage, or a larger oversize if there is damage that can be fixed by a more aggressive rebore. You might, just might get only a hone recommended, but it would have to be pretty good for that as most machine shops won't want to risk their reputations, or a warranty claim, if the engine proves to be smoky etc. If they advise a rebore, they will tell you what size it needs (+0.010", +0.020", 0.030" (most common first rebore size for US V8s, not sure about the Triumph six), 0.040" and 0.060"), and will either offer to supply pistons or leave it to you to buy the appropriate oversize piston. Any rebore cannot be done until the shop has the pistons, as different designs/makes will require different clearances in the machining. The rebore finished size is dictated by the actual set of pistons to be used, in other words. If I'm having the block and crank done and a chemiclean of the coolant passages, I'll usually go the whole hog and have the rotating assembly balanced. Obviously this will cost more, and they will need block, crank, rods, pistons, flywheel, clutch cover and crank damper. If they balance these they should mark the clutch cover and flywheel for you so you can assemble correctly when you come to put the engine together. Ideally the clutch will be zero balanced so you can fit a new one at a later date without upsetting the balance. Hope that helps. You can always measure bores, journals etc. yourself and make your own call. Looking at your crank photos, I would expect that to need at least a polish, and I would want the bores measured for wear and ovality, if you don't have the kit yourself and don't know the history of the motor. I stress - this is only my opinion.

Not much left for the batteries then, I'd guess....

OK, that's good! There are so many variables - if you know the engine's history, have driven it before the strip-down etc. it is possible to make these calls. Fifteen years ago I ran a big end bearing in my Mustang's 393 on the Estoril race track during a touring run, so it came home on a trailer. I dropped the sump and removed the relevant cap, to find the shell down to the copper but no marks on the crank. The engine was a new Ford Motorsport crate motor, which had only done 3,000 miles since installation. It turns out Detroit had told me the wrong sump capacity (crate motors have to be shipped empty, and come on a pallet with a new, unmarked dipstick taped to the pallet. Sump was an aftermarket Canton unit - suffice to say Ford tech said it was a 7 litre sump, when it was actually a 10-litre, which I found out the hard way....). As I knew the history, I measured the journals with a micrometer and polished the crank in situ, fitted a new set of big-end shells (mains not possible with the engine in), and 45,000 miles later all is still fine. Most of this is down to luck, I'd say.

Sorry, may have missed this - how many miles has it done? Something to consider is that it is possible for the bores in a block that look good to be worn oval. On the power stroke, as the piston is pushed down it exerts sideways pressure on the block, at right angles to the crank axis. Speaking entirely personally, I would either measure the bores or get a machine shop to do it. I'd have a chemiclean done too - I'm always amazed at the difference between a home scraper job and what the machine shop can get out. That's very much a personal opinion and I appreciate that you may be wanting to spend no more than is absolutely necessary - I'd rather button it all up knowing that I shouldn't have to touch it again for years. There is a school of thought that suggests that if you're not going for machining work, it might be better just to clean and reassemble as the parts will have worn together over the years. Depends really on what the compression figures were, what the oil pressure was and whether or not it routinely ran hot.