JohnD
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Posts posted by JohnD
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+ one for ahebron's advice! And especially rear light clusters. You need a earth wire that will rake the current from ALL the lights at once!
After all, you could be at night, lights on, indicating AND then brakes on!
Joh
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Bridge Auctions have a unique (?) business model - they sell cars by lottery. You buy a ticket and wait for the draw. This time they ae selling a Spitfire, so this is an opportunity for someone to become an owner, perhaps for the first time, for £6!
See: Here is your chance to win our 1979 Triumph Spitfire 1500 : Bridge Classic Cars Competitions
I know nothing of the car and have no connection with Bridge Auctions. Just seems to me a good way to find a new Triumphero!
John
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Johno,
You're "getting different bore dimensions from different locations" . Is this cylinder bores? How are you measuring them? The 'proper' instrument is a bore-micrometer, a very expensive item! Another way is to put a naked piston ring in the bore, push it down with an upside-down piston to level it, and measure the gap. This won't tell you the absolute bore diameter, but allows you to compare different bores and by positioning the ring at different heights in the same bore, to tell if there is wear in the bore wall. Rebores, and the pistons to fit in them come in +10thou increments.
The crank journal diameters on the main and big ends can be measured with a Vernier caliper (very cheap!) to a tenth of a millimeter (4 thou), but best is to buy a micrometer, 1-2" range which will measure to less than a thousandth of an inch. Lots for sale on eBay for less than a tenner. Since even a precision instrument may go off, look for a gauge block in the same range. Micrometers may be adjusted but its probably easier to know that yours is +5%, or whatever.
But even a Vernier will let you compare journals. Then, regrinds and the oversized bearing shells to fit them, also come in +10 thou increments. Another way (I like 'other ways'!) is to use "Plastigauge", strips of soft plastic that to assemble into the bearing, then take it apart to measure how wide the plastic has been spread. It's a surprisingly accurate way to measure clearance!
John
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I don't doubt Colin, but I use an oil-filled gun, that I keep between uses in an little old oven tray, as the oil seeps out. Very Triumph!
There should be a blanking plug in the bottom of the upright, that you take out and replace with a grease nipple as required.
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2 hours ago, Ian Foster said:
John
Aluminium honeycomb is the most efficient way of producing sandwich construction and is probably best suited to reasonably flat panels. It can suffer from delamination if in high performance yachts where they experience severe slamming. The marine industry typically use end grain balsa in deck mouldings and foam in sandwich construction hulls.
Ian
Ah! That's why I used paper honeycomb! A LOT cheaper than aluminium. 'Slamming' isn't something seen in cars even competition ones, until disaster happens:
Gel-coat + single layer matt outer coat, honeycomb attached with expanding polyurethane foam, inner coat single layer of glass tissue/resin.
Result:
That roof was stiff and solid at 124mph on the 'Ring, but when the roof hits the road:
Hey,ho that's motor racing.
John
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Quick wipe with thinners and carry on with the next, next can!
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Micmac,
Glad to help! Even when unasked. Please ask questions if needed, the only stupid question is the one you don't ask!
Ian, thanks for the link! When I built my Silverback, as well as the hatch back door, I built GRP roof and doors,both incorporating honeycomb contributing to enormous stiffness and lightness. EG doors 5kgs with handles and hinges.
John
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Thank you, Ian! "Blue rigid foam"? Can you be more specific, please? Is that Extruded Polystyrene (XPS) or "Blue Board" to the construction industry? That would not absorb resin as it it 'closed cell'.
And what 'glue' did you use? I ask that because I used polyurethane foam, because I knew, from experience, that polystyrenes DISSOLVE in the resins used with glass fibre! Does carbon fibre use a different class of resin?
On taking a mould from your model, and making it 'non-stick', covering it in body filler would work but you would risk making the mould fractionally bigger than the model. Paint, polish and PVA?
Or, and this seems to be little known, ordinary brown parcel tape does not stick to GRP resin! Covering your model with tape will not significantly alter its dimensions. A coat of release agent does no harm.
I've found this very useful when taking a mould from rusted car panels, which would otherwise need to be virtually restored with filler. Just bridge the gap with tape!
John
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I had to replace mine after a ding at Thruxton. I found it was useful to make up a 'jig' from a pallet to support the 'new' part, and hold it at the right height and alignment while I welded it on.
Use the dimensions quoted in the WSM to ensure it's on straight!
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Ian Foster,
Yes, I like that latest, latest box design even better! I made a rear hatchback door for my Silverback, race Vitesse, by taking a mould off the original outer skin, but as I couldn't be bothered to copy the inner surface, I just glued polyurethane foam inside it and covered that with GRP, rather like, I suspect, your rudder. But I found that the foam soaks up resin! As a result, it turned out much heavier than I hoped. (the roof, in GRP and honeycomb, weighed a third of the steel original) Did you find that with your rudder?
Do you have a heater in your car? You can use the airbox under the intake for that, below the windscreen, as a useful source of fresh air. I did that on Silverback, for different reasons:
Johnny,
Our engines don't have "swirl", they have "squish"! The combustion chamber doesn't cover the whole of the bore, and that flat area away from the plug is designed to almost close completely at TDC, thus 'squishing' the mixture on that side towards the plug, causing a turbulent mixing of the charge.
But this is designed to just mix the charge, like stirring coffee with a spoon. "Swirl" is a later and more sophisticated idea, to produce a stratified charge, with a small, rich area in the middle for easy ignition, and the rest of the charge lean for economy and emissions. It relies not only on the shape of the inlet duct and the chamber, but how the injector squirts, usually directly into the chamber. Can't do that on our old lumps!
John
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Ian Foster,
What a great design method! You're modelling the box in foam and shaping it with filler? How will you construct the final part - cast it in GRP? More detail of your method, please!
You make it very clear how you can't make the box have more volume by being thicker - can you make it wider? The double disk shape was originally to contain two cylindrical filters, but you plan to use a remote conical filter, so your box may be any shape. The bigger the better, as the bigger the slower the air and the higher the dynamic pressure. I'd also look at the transition between the cylindrical duct and the flat sided box - flow easily becomes turbulent in such a transition so make it widen as quickly as possible to slow the air and keep it laminar.
Lastly, I see you already have a conical filter that attaches to a 2"(?) duct. Much better than Triumph's narrow hoses! But 3" filters are available (see my post page 1) and resistance to flow along a 3" duct will be a fifth of that along a 2" one! (1/2^4 vs 1/3^4 = 1/16 vs 1/81)
John
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On 26/03/2024 at 15:25, johny said:
I know its a very involved subject and this is Wikipedia's take on it:
'Turbulence in the intake helps to break up fuel droplets, improving the degree of atomization. Better atomization allows for a more complete burn of all the fuel and helps reduce engine knock by enlarging the flame front. To achieve this turbulence it is a common practice to leave the surfaces of the intake and intake ports in the cylinder head rough and unpolished'
johnny,
It's important to remember that the Wiki is not an encyclopaedia, researched and written by acknowledged experts, nor are its articles peer reviewed by other experts before publication, as are papers in academic journals . In effect it is a message board, just like this one where anyone may post. Some who post may have the authority and expertise to teach you, others are winging it, a few are out to mislead you. This disadvantage of the Wiki is balanced by it being open to correction, but its managers cannot monitor every entry and every line. The Wiki is a useful source but cannot ever be a reference!
You quote the Wiki article on the Inlet Manifold: Inlet manifold - Wikipedia and the paragraph there on "Turbulence". It refers to breaking up pools and drops of fuel on the duct walls where a rough surface is desirable to promote turbulence. I absolutely agree, but this refers to the 'boundary layer', the air is slowed down and made, yes, turbulent!, by contact with the duct wall. The thinner a boundary layer the more laminar flow will there be in the duct, which is most desirable, as turbulent flow is chaotic and offers more resistance, so normally a smooth wall is best. But in these circumstances, a rougher wall and a thicker boundary layer gives a better compromise.
If you find this subject interesting, may I offer you another online article, this time from NASA who really do do know their aero! Boundary Layer (nasa.gov)
John
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Yes they do but not to induce turbulence. A matt surface will tend to discourage 'pooling' of excess fuel, and promte consistent mixtures.
John
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Yes to Graham. A corrugated hose makes the functional diameter for laminar flow about a tenth smaller, less on a larger tube, more for high flows. What's a high flow - a Triumph engine! A 1500 at 4K pumps 3000 litres of air a minute! Imagine that through a pair of one inch tubes! That's over 60mph, just in the tubes!!
Mjit, yes. Triumph penny pinching could easily have been the reason. The production cost of a deeper box and wider tubes would be in pennies per car. But dear man, you're in London! It's "maths"! Physics really, aerodynamics, but maths.
Johnny, Less turbulence, more "swirl"! Modern engines with very lean combustion use a stratified charge, richer at the ignition point, achieved by some very clever swirl and "tumble" in the induction, where turbulence which is essentially random wouldn't do.
JOhn
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It's a further mystery why Triumph provided TWO air inlets to the small chassis cars' air boxes. It's a well known factor and must have been to their designers, that the resistance to flow along a tube varies as the fourth power of the radius. That's RxRxRxR. Halve the radius and the resistance rises SIXTEEN times! (2 to the power of 4, 2^4) Instead of the two, a single intake duct with double the radius would have sixteen times more flow under the same conditions!
Then, they seem to have designed the smallest possible airbox, that fitted tightly around a reasonably sized air filter. Another well known principle is Bernouille's. Air pressure falls as its velocity rises - that's why an aircraft's wing gets lift. Air flowing though a small box will have a lower pressure than in a large box, where it will slow down and raise its dynamic pressure. So as large an airbox as possible is desirable.
Triumph, possibly persuaded by Lucas, must have learnt the lesson when they fitted Pi to their cars. A large airbox around the air filter and a three inch duct to the plenum tube, which is only three inches in diameter. So on my Pi-powered Vitesse I built a six-inch plenum/airbox, and mounted the air filter directly to the front of that. Given the cramped engine bay on the Vitesse, this puts the filter in the cold airflow alongside the radiator, and enlarges the plenum by four times! See below, OE plenum fitted, six incher ready to go.
John
PS The junction between filter and plenum is still three inches across, but that's an 'orifice' where the Bernouille rules don't apply, because of turbulence.
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The chemistry of rust removal is that any acid will convert iron oxide into iron 'acidate', in this case iron citrate. A 'strong' acid, like sulphuric or hydrochloric will attack the native iron as much as the oxide, so 'weak' acids are used,usually organic acids like citrate.
The point about phosphoric acid is that iron phosphate is almost insoluble in water, so it remains on the part, while other acid's products will wash away. So for heavy rust, as in the example above, use citrate/acetic etc first ( or electrolysis).
Once all the old rust is removed wash in clean water. Flash rust will occur! But a second treatment with phosphoric will convert that to a layer of phosphate which will not rust any further and is an excellent surface to cover with primer and paint.
John
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"Appears to be a good deal on NOS, NGK BP5E plugs on Ebay. £6.70 for 6 (inc postage)"
Spark plugs for £1.10 each? If it looks to good to be true, ......
NGK are a favourite makes to be faked.
John
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Delete "safety glasses". If you wear prescription glasses, the 'safety glasses won't fit over them, and will steam.up. Far better is a Visor, worn like a welding helmet.
And if you're as old as I am, overalls with knee pads!
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Wow! I hope you bought a lottery ticket that day, AND a diamond tiara for with the prize you must have won, because she's worth it!
More seriously, lorry workers will use a crib, a stack of timbers that lock together, under the vehicle. An old pallet can be a useful source.
John
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Yes, mobile, in your breast pocket. If your car falls on your leg, you can call for help. If it falls on your chest, you won't need to.
John
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DVD,
Someone who makes Spitfire looms might add the wiring you want for upgrades, if you specify where the new wiring must go and the position of the components it supplies, to make you a bespoke loom.
I can't suggest who you should ask, but you are clearly good at research!
John
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Direct drive compressors, I was warned, are much noisier than belt driven. I didn't listen, and after I bought one, I couldn't hear!
I built an enclosure for it, to sound "proof" ( shouting helps) and then had to fit an extractor fan to stop it overheating!
John
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Who said "don't left foot"? Before Euan?
Yes, it is a thoroughly competition-related technique, NOT recommended for road use! For a reasonable guide (I don't say 'definitive'!) see: The Definitive Guide to Left Foot Braking - Driver61
John
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Rather than merely a case of not the best pads, I fear that "gradual loss of brake performance" over a trip of 200 miles (?), with the symptoms described, indicates a loss of mechanical efficiency in the brake system. Thorough inspection needed, starting with the state of the fluid, movement of the master cylinder, state of the flexy hoses and movement of the cylinders. I'll stick out my neck and say the last - are they both moving, in both calipers, no seizure?
Sorry, but just changing your pads in this situation is unlikely to improve matters.
John
The Last Racing Vitesse, UDF 772H, AKA SofS
in My car's history
Posted · Edited by JohnD
This is SofS. I'm trying to find out more of its history.
I first met the car in the late '90s, when I raced Old Blue Vitesse against John "Trioomph" Sadler:
After Old Blue went to the Great Garage in the Sky, I built Silverback, but then that was downed on the Nurburgring by someone who thought he was Manfred von Richthofen in a Gp2 Porsche.
Two weeks after that, this car was on eBay after twelve years in a barn and I had to have it! Needed a lot of work to get it back on track and inherited aa lot of parts from Silverback, so it's the son of Silverback, or "SofS"
It's now the only Vitesse racing in the UK, and one of only five that I know of in the world (the Candy Box in the US, in Malta, France and New Zealand). Before John Sadler, I think it was owned and raced by one "Barney Rubble" Barnes, who I remember racing a Spitfire and beating me. He must have been a TSSC member, but I've not heard of him in years. I'd love to be able to ask him how he became the owner of this car and what he did with it, to add to its history. If anyone knows or knows of Barney, please ask him to contact me? If you do, contact me by PM, please, and I'll send my email for Barney to use.
Thanks!
John