Nick Jones

Agree that the crank pilot bush can be part of the problem, as can a distorted engine backplate. Main problem is the tip bearing size is too damn small for forces involved and lube is marginal, even when oil levels are correct. Nick

Pic of the plug in my son's Spit I have also seen people use a standard core plug (freeze plug in US). Nick

The original extends downwards 20 - 25mm and has a machined ring to act as an “up-stop”. Tolerance set as Pete describes above. With the flat plate there is nothing to stop the gear climbing out. I take the point that the direction of gear cut pulls the gear down in the normal direction of rotation, but given that both cam and oil pump are oscillating loads, some gear chatter is likely. Also, should the engine get turned backwards for any reason (not very common I know.... but...) the gear will tend to climb out of mesh and disengage from the oil pump drive. It won’t necessarily re-engage when engine turns the correct way again. Bad things will happen. So, though clearly a low probability event (Ian has run for 10 years like this), it would be a high consequence event. I wouldn’t do it like that, I’d leave the pedestal undisturbed and simply plug the hole leaving the engine mechanically unchanged. Nick

Agree. Was recently doing this on my Vit CV. More packing under the rear side-rigger body mounts or less under the boot riggers/shock towers will open the top up. This will only open up the top and not close up the bottom so looks like once parallel, the gap might be a bit big. It is possible to change this by shuffling the rear tub forward relative to the bulkhead (I had to do the opposite on mine), but gets considerably more involved. suggest slackening the rear roof bolts before doing anything. Nick

I’m quite surprised you haven’t had problems with that Ian. The distributor pedestal should be left in place as it holds the oil pump drive gear down. Just don’t turn you engine backwards. On sons Spitty EFI I turned a stepped bung with an o-ring groove and it just pushes into the hole left by the distributor. Nick

Yes. Done it recently. May need to take the air filter box off on a standard car. Nick

I think that might be long enough ago for them to be “proper” ones. Those sold now (or at least the pair I own) have a different shape to the bottom of the seal groove compared to original ones. I’ve tried seals from various sources including genuine Girling ones and none have produced an acceptable result. Best result was from some well-used Girling ones, but pedal was still too long. New Girling seals bound them up solid. Gave up and bought an old pair to refurbish. They work fine. The others are living in a box and free to collect. Nick

My experience of new type 16 calipers (GT6/Vitesse) is entirely negative. I don’t know anyone who’s tried them who was happy with them, but I do know / know of several that weren’t. They don’t self adjust properly so you end up with an unacceptably long pedal. Spitfires use the smaller type 14 calipers, which I have not tried. They are generally straightforward to overhaul. Parts are easily available. I usually get kits from Bigg Red who also do stainless steel pistons. They will do the refurb for you too if you prefer Nick

I thought about using one of the oil hole bearings. I didn’t because a). My input shaft had the angled hole and re-drilling it straight would be hard. b). The centrifugal force thing again. The machinist used a cobalt drill. Nick

Yep, lubrication is key. Rollers don't need alot of lube, but they do need some. Seems like they ought to get lots, but they are in the eye of the storm, as it were. The oil gets centrifuged away when the engine is running. Originals with 1/2" tip had the oil hole drilled from here....... .....at an angle, to here. No real reason for it to go where it is needed - gets centrifuged away. Later ones start at the same place but go straight..... Coming out mid-roller. Some chance of this working, but centrifugal forces are still against you. This is a single rail Dolly 1850 part. Someone (I forget who now) told me that the late Sprint and Stag boxes had the oil hole drilled in the gear so oil was reliably forced into the bearing and it improved their life considerably. Thought it worth a punt. Left field alternative (not sure I'd try it behind a six though) slightly damaged mainshaft tip turned down to be parallel again, Fitted with an oilite bush - interference fit on the tip (fit after synchro hub!!), running fit inside the input shaft. Was possible because the mainshaft tip was only lightly damaged and the input shaft bore was ok. You could also (maybe should) use a PB bush with a spiral oil groove on the OD - would be stronger. So far this has lasted 6,700 miles behind an injected 1300 in my sons Spitfire, which is already 6k more than many were predicting. Was cheap and easy. Nick

No secret. I worked it out for myself but later discovered that Mike Papworth does the same thing. It's a NK1820 18id x 26od x 20 long roller bearing, which has a hardened outer sleeve of 26mm OD. It has no inner sleeve and is intended to run directly on the 18mm shaft tip. Note that you can also get inner sleeves so could potentially tidy up an existing mainshaft tip and fit one if it wasn't too horrible (mine was!). This is what my tip looked like and the input shaft - I think it had been run low on oil and maybe towed a long way - loads of sparkle..... Which washed out looked like this. Knackered. Machined out to this (it is hard, or at least surface hard, but the machinist managed it with a suitable insert tool and didn't even damage the insert - he's good though). Note the oil hole at the bottom, the original is obscured by the new bearing sleeve (and IMO is in the wrong place anyway). I forget the exact details, but IIRC I think it was a light interference fit for the 26mm sleeve and 21mm deep. OIl hole other end in tooth root where meshing will give a pumping action. New bearing fitted. You can just see part of the original oil hole at the top of the bearing (later versions such as 1850 dolly and TR7 had this lower down, feeding the middle of the bearing) and my new hole at the bottom. Hope this is useful. Nick

Have plastic fans knocking around from various Triumph sixes - will see if they have numbers on. Nick

Good chance of that I reckon. Must sort similar for my Vitesse. Nick

Beer, in Devon today. Shakedown cruise of about 60 miles in all with a very nice cliff-top walk too. Even managed an ice cream! Petrol under £1/l (just) but traffic pretty much normal - moderately crap. Car behaved perfectly - even self-built diff seems quiet. Can’t hear it with top down anyway, whereas I could hear the old one. Nick

Replacing is just a matter of unscrewing (good luck!) and screwing in new ones. However..... after sitting around for 15 years I’d be be fitting new wheel cylinders (or new seals at the very least). I’d also be renewing the seals in the calipers (possibly pistons as well if rusty/loosing chrome) as well as refurbishing/renewing the master cylinder and renewing all the flexi-hoses. When everything is working as it should, Spitfire brakes are pretty good, though if you mostly drive over-servoed moderns you’ll find pedal pressures higher. What does not help with this is that many of the pad materials sold for the Spit are too hard and only marginally suitable. Strongly advise buying Mintex M1144 compound pads which have great bite from cold. Nick

On my Vitesse the tyres are on 100+ cross-spoke alloys, 6J On the GT6 they are on steel wheels but the 5” version (late Spit 1500?) Nick

They will compress until the bump-stop (in the damper) is reached. Whether this causes tyre/arch contact depends on wheel and tyre combinations and how wide the arch lip is. To be sure/scientific about it you could fit the damper without a spring and jack up under that corner until the bump stop is reached and see where that places the tyre. Significant effort though. I can tell you that on my Vitesse, 175/70 tyres on 6J wheels, ET13 do make occasional contact, even with slightly rolled arches, but nothing I can't live with. Fffset/ET is important. What wheel/tyre combination are you wanting? Nick

I think the problem is that the locking washer is thinner than the originals so the nut (39) screws on further. You could lap the back of the cup as you say or the front of 34. Or perhaps re-use the original cup (though might still be tight due to the lock washer) - I've not encountered a cup beyond use to date. Nick

+1. Great wet/damp grip and reasonably priced. Have them on my Vitesse and GT6. Nick

If the mainshaft is knackered (they usually are) and the bore in the input shaft also, it is possible to buy new mainshafts with larger tips (18mm vs 1/2") and machine out the bore of input shaft to take a needle roller with outer sleeve. I did this on my GT6 gearbox last year. I also had a hole drilled through the tooth root so that the meshing gears would force-feed oil to the bearing, as lubrication is a problem with these. http://sideways-technologies.co.uk/forums/index.php?/topic/7535-nick-chriss-gt6-mk-3/page/7/#comments Only done 500 miles so far, but so far so good..... Nick

Found a post I did on Sideways a while back relating to crankcase breather experimenting on my (now departed) 2.5PI. For background, the thing slobbered and chuffed like an old steam train and "sweated" vigorously if driven moderately hard. It also burned lots of oil. However, as it produced excellent results on compression tests (probably because every test was effectively a wet one!), this fed my denial that the engine was actually completely knackered. I therefore expended alot of effort treating the symptoms before taking the engine apart and discovering that the bores were badly rust-pitted, and well worn. http://sideways-technologies.co.uk/forums/index.php?/topic/5682-crankcase-breather-mod/&tab=comments#comment-75002 That said, the revised system with PCV worked really well at containing the slobber and I left it on after the engine rebuild. Nick

Pete, I’ve cooked a couple of failed NGKs with a blow lamp and failed to revive them. Never had that fail before. They were virtually new with just minutes of run time in my PI. Not even particularly fouled visually. I also killed a complete set in our Nissan Primera GT by forgetting to plug in the coil pack after doing some other work so they got flooded. That really had me going as it had been running earlier that day and I’d only unplugged the coil pack to improve aces to a non-engine related part. Then no spark anywhere. I went to three different shops to avoid buying NGK to replace them! Nick

Some NGKs stop working for ever if they ever get significantly fuel wetted. Especially when newish. This makes them worthless for PI. Champion..... yeah. I wouldn’t even use them in garden equipment. Just had one fail in my lawnmower (internal resistor failed - went to 26k) and take the magneto with it. Then a week later the same failure in my strimmer, though thankfully the magneto survived. As Nigel says, Bosch 3 or 4 prong for the win. Triumph engines love them. W7DTC (non-resistive, very hard to find now), WR7DTC (resistive, also getting hard to find) or FR78X which seem to be the easily available modern ones with 4 prongs. Just fitted a set to the Spit. Nick

I got one bored out for the GT6 last year to go with one of Mr Papworth’s large tip mainshafts. The bore was knackered anyway. Put a sleeve and a roller bearing in it. Also got a hole drilled through the root of the gear to the back of the bearing so the meshing gears will force feed oil through. Bit on the gearbox rebuild here. http://sideways-technologies.co.uk/forums/index.php?/topic/7535-nick-chriss-gt6-mk-3/page/7/#comments One of the boxes I took apart looking for usable parts had a loose slug as a mainshaft tip. It hadn’t failed..... but I don’t think it had had much use. Nick

It’s normal for the hub to be a bit tight and it’s not because of the spline. Usually they’ll go on by hand until you can just get the nut started - unless there is a spline problem or the threads are damaged (common). The shaft has a land inboard of the splines which is intended to be an interference fit inside the inner spigot of the hub where the inner bearing fits. Whether the degree of interference was intended to be enough to expand the spigot and hold the bearing, I’m not sure, but this does frequently seem to be the effect. This is what makes the last 10 - 12 mm tight. The other side-effect is that the splined shaft becomes unusable when the first couple of threads on the end of it get pulled off when using the nut to try to draw everything together. You can get around that by putting the whole assembly in a press, though that is hardly convenient. It’s an unnecessarily complex design that brings more difficulties than benefits IMO. Nick