john.r.davies
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Posts posted by john.r.davies
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All, esp. Bryan,
I recently tested a new temperature sender, using a water bath gradually heated from room to boiling temperature. I measured the resistance with a multimeter and the actual temperature of the sender with a remote infrared thermometer.
The resistance of the sender varied from 1 Ohm at 40 degrees C to 0.1 Ohm at 100 degrees C. There was a little 'sag' in the straight line between these two points. I couldn't heat the sender any more, to working temp. without seriously modifying a pressure cooker, and she wouldn't let me.
An old sender had a smaller range, with a higher resistance when cold and almost the same when hot.
Hope that helps!
John
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All,
There has been a considerable correspondence about this problem with GT6s and Spitfires in the more torrid conditions of US Southern States, on the Totally Triumph Net ( http://www.totallytriumph.net/cgi-bin/dcforum/dcboard.cgi ). Sorry, I can't remember the exact reference, but there is a good search facility on the site.
One idea that caught my imagination was to fit a length of ducting from behind the radiator grill to the arch of the bulkhead, directing cooling air into the gearbox cover, at least when in motion. It would not be beyond wit to add a fan in the intake to the duct. The thread(s) contain several other suggestions for insulation methods.
Good luck
John
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My thanks to all for your advice. Since my first post, I have replaced all the ignition components, and changed from electronic (Newtronic) to C/B. No better. Doing all this, I haven't tried the choke trick yet.
New plugs? Okay, seems like a good idea - I'm desperate now. John
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Richard,
Yes, M/u timing double checked
Jonlar,
It was changing friom Newtronic (ex-Pirhana?) to good old points that cured the high revs misfire. Thank you, I'll chang the condensor - any idea what the curent Halfords part number is? One of them looks about the right size, but no Microfarads quoted.
Andy, Thank you, I'll try that. What should I do if it cures the problem? The plugs are already very sooty indeed.
John
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All,
I'd be grateful for ideas, please, from the Pi experts. I've installed Lucas Pi in a Triumph 6 cylinder engine from a saloon, that was originally on carbs. TR camshaft, flowed head, raised compression(10.5), 6-3-1 exhaust. The fuel pump is a Bosch, the Meter Unit is reconditioned and all the pipework and injectors are new.
Failure to rev to the limit was traced to an ignition problem, after prolonged search for a fuelling fault, but now there is a distinct lack of response. Slow acceleration is fine, but it will bog down if the accelerator is snapped open. If it were still on carbs, I would look to the needles or the dashpots.
Fuel pressure 110psi. Vacuum at M/u instantly falls to zero. The engine runs well with an open vacuum control, but ridiculously rich. The butterflies are synchronised. Ignition 11 BTDC, centrifugals work correctly (+13)
Where else should I look? Is it still the ignition, Stupid?
John
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Andy,
No argument with Ron, but I found it easier to keep the rear engine plate on the block, and bolt the arms to that. This means that you can't install the rear crankshaft seal housing , so now I have a old rear plate, with a hole cut out for access to the housing. I also can send you pictures!
The alternative is to leave the housing until the rest of the engine is finished, Rest the engine on bench or floor, remove the plate, install housing and replace plate.
John
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Terry,
This style of gauge is a "Bourdon" gauge - there is a coil of slightly flattened tube inside, one end fixed, the other linked by a gear train to the needle. As the pressure rises the coil, er, uncoils, and moves the needle accordingly.
If you have oil in the gauge, then it is leaking from the Bourdon coil, or else at the connection at the back and into the body of the gauge. The first is terminal, I suppose, the second might be fixable by gentle tightening.
I don't think oil will "spray" oil into your car - the connecting tube is very fine, so resistance is high and flow will be low, but it will certainly drip, drip and make a mess.
John
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Richard,
This won't help getting them out, but will help puting them back in and will ease future manipulation.
All modern cars have looms that connect to the electrical units by multiway connectors. I've rewired my dash - indeed the whole car - with this in mind. Now, once a gauge is loosened from the dash, it can be drawn through the hole, the multiway disconnected and the gauge removed. In best Halfords tradition, "Reinstallation is the same procedure in reverse".
I bought a whole set of multiways from Vehicle Wiring Products ( www.vehicleproducts.co.uk ), that included enough for the whole car. Cut the wires, crimp on the multiway connectors (solder if you are obsessive like me) and insert into the M/way. No need ever to grovel on your back, in the dark, trying to insert spade connectors into the back of an invisible gauge.
John
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Ron,
Valve guides letting oil into the chamber are not the only cause of smoke on the overrun. The other is poorly sealing piston rings.
You have "the same setup" on your B with no problem. Did the TR work include new piston rings? And if so were the bores deglazed/honed? And if so, did you run in the new bores?
If they are letting oil up, they may let gas down - have a look through the oil filler - is there an out-draught of gas, or just a breeze?
John
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Tony,
I'm in the middle of converting to Pi, and the Lucas pump I bought as NOS (Original box, original seals on connectors) is not up to it. Don't know why but after a few miles, or warming up, the pressure falls and the PRV starts to oscillate. So I'm going for a Bosch.
On supplier, I haven't talked to Revington, but Malcolm Jones at Prestige is most knowledgable and helpful. We are in the middle of an email/'phone discussion on how to achieve what I want. Talk to him and to Revington and consider your own verdict, M'lud!
John
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John,
That post date IS the 11th, not 1st?
If you're serious, have a look at the Stack Dash Display system. Does everything you want and then some - if you want to spend nearly £1.5K. Spend twice as much and you can have it all on the steering wheel, just like Herr Schumacher OR on your in-car videoscreen.
See the Demon Tweeks catalogue for instance.
John
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I won't poll this, but hope that all you who took part will agree to thank Mike Hughes for the organisation of the Track Day. For racers, an excellent shake down with the opportunity to get advice, ideas and craic from fellow Triumphists, for non-racers an introduction to really using their Triumph and a thoroughly good shop window to Triumphs for the Real World from the publicity - lookout for 'Retro' about June, the 'gentlemen of the Press' were in attendence.
John
Thank you, Nigel.
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Andy,
The metering unit has two pressure connections - the top one for manifold pressure, the lower for atmospheric. In effect the meter compares these two.
If you connected the 'atmospheric' to the downstream side of the fan, well upstream of the manifold, then that would be the standard for comparision with the manifold pressure. Wouldn't that allow the metering unit to do its job?
Jemgee,
O-level physics spot on, but you would need a fast flow of air around the outside of the plenum to drive the venturi. A pipe connection to a point on the car where lift is generated would work just the same, and by Sr.Venturi's effect as well! But, as I understand it, the air starvation at the rear cylinders is due to the flow from the front being robbed by the front cylinders. A further extraction of air from the rear of the plenum is going to make matters worse!
John
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Jonlar,
Worth a try, however someone was offering "electric turbo" - a fan - on a US website last year and got thoroughly rubbished. But don't knock it, etc etc.
John
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Bob,
There's always a compromise, between the ideal and what can be done. The ideal is a carefully crafted intake up in undisturbed flow, with a matched plenum right underneath - see F1. With your larger plenum, I doubt if you will blast your rivals into the weeds (!), but it is likely to make a difference.
None of us here (I suspect) is in the position of making microchanges to our engines or cars, testing the result on dyno or windtunnel and then reiterating the process, so we must do what seems right, by eye or seat of pants.
Try a bigger duct as your next iteration, perhaps junking the filter box and sticking one of K&Ns wide range of filters out in front of the radiator?
John
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All,
If I may offer my comments:
Advantage No.1 of a plenum is, as Bob says, cool air. No amount of directed air from a filter is going to cool intake from the engine compartment without a tin box around it.
Advantage 2 is raised pressure. Air passing through ducts of any sort has a velocity, and as Bernouille says, pressure is inverse to velocity. A plenum allows the air to slow down as it enters from the ducts, so that it has a higher pressure for ease of induction.
So make the plenum as large as possible.
The standard TR plenum is a tube, whose resistance to flow is inversely related to the fourth power of the radius, so double the radius, the resistance falls to one sixteenth. And you get a nice big plenum.
Ram-air is a bit of a myth at less than 100mph, and the intake size/expansion geometry has to be carefully matched to gain an advantage. NACA ducts are great for enclosing nice smooth laminar flow - I'm not confident of that on a TR's bonnet.
Roger's racing friend is right about pulses from the inlet valve, and the standing wave in the inlet manifold. This can be used to tune the inlet, just like an organ pipe, to raise the pressure at the inlet valve, while reducing it at the inlet. This needs longer than usual inlet ducts, and again, there is an inverse relationship. To resonate, the inlet length required is inversely proprotional to the input frequency, or in this case, revs (look at organ pipes - the higher the shorter). Revs 4-6K happen to need pipes 600-400mm long!
On the affect on mixture to the back cylinders, I can only report work in progress. I have turned the plenum around, to accept air from the high pressure pocket in front of the windscreen, to minimise air flow into the engine compartment. So No.6 cylinder is first in line for air. I'll report back.
John
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Taffy,
No argument with the other John ©, but I've built engines on the floor and I've built them on a stand. Trust me, a stand is better!
I would buy one with a C-shaped base, rather than a T-base for more stability. Less than £50, and hire charges would be half that for a week.
Mounting on the engine back plate is easier, and possibly safer than directly to the block. If you have/can find an old plate, enlarge the hole in the middle to access the rear crankshaft oil seal housing, to strip the block completely on the stand, and rebuild it too.
John
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All,
Of aall the UK Triumph performance specialists, Moss(TriumphTune) would be the last I would choose. They have the heritage of Terry Hurrell. but none of the experience, as he is no longer associated with the firm and they will farm out the work.
UK specialists with real, current race experience include cambridge Motorsport, others mentioned above, or Jigsaw Racing. The proprietor of the latter. Mark Field, has a long personal experience of Triumph racing, starting in Spitfires and then in TRs. He has a solid reputation for advice and supply of performance related parts - and I'm not related to him!
John
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All,
Are 250 engines so different from later Triumph six cylinders? NR and CRC above write of hammering the pistons out with a timber drift, implying that they were pushing them out downwards. This doesn't work with later engines - the pistons go in/come out from the top.
Educate me, please!
John
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All,
I know about trunnions in Herald based cars, not TRs, but guess they may be the same. The problem is that bronze wear particles remain suspended in grease, leading to accelerated wear. In oil, they fall down into the bottom of the trunnion, off the threads - that's what the vertical slot in the threads is for.
As for oil 'falling out' of the trunnions, the problem there is that unlike the original parts, modern parts have a steel plug, like a core plug, inserted in the base of the cylindrical casting. Some plugs don't seal well, and the oil leaks out. If you have new trunnions, clean and degrease them, then apply some epoxy glue around the edge of the plug, inside the trunnion, as a permanent seal.
Then your oil will stay in!
John
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SUCCESS!!!!!!!
Thanks to Tim, thanks to Richard, thanks to all.
Yes, churning the engine - I used my daily car and a set of heavy duty jumper leads to assist the 'native' battery - eventually does the trick. I had the injectors sitting in a catering sized coffee tin that accumulated about a half a pint of petrol before I had even four injectors working consistently, and it took half an hour of churning, tapping and pulling to get that. Then plugged in the injectors and spark plugs, quick flick of the starter and away she goes!
I thought afterwards: Presumably it's the air that must be got out of the lines and injectors. If the injector pointed upwards, would it purge more quickly than hanging them point down in a tin? A "purging jig", to hold the injectors point up with a deflector to catch the spray and a drip tray to catch the fuel, would be a nice little project. But I have lots else to do to the car first.
Thanks again!
John
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Richard,Tim,
With help and advice like that, my engine won't DARE not to start!
Thank you both - I'll report back (May be going to Cardiff this weekend, so later)
John
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Tim,
Thank you! That makes a lot of sense.
Just one explanatory, please - 'tapping the injector'.
Is that tapping the body, or the spike at the business end?
Best wishes,
John
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All,
I have a similar problem - newly installed Pi engine, won't start, but will fire with QuickStart, so ignition more or less right. No fuel from injector OR from fuel line without injector on turning the engine over on the starter. Full pressure at meter and good back flow from PRV. Meter correctly set (No.6 port just opening at No.1 TDC firing stroke).
Is the problem that the fuel system has not primed? Will try A.Moltu's solution (above), but engine cannot run. What is the priming procedure? Just flog the battery until it does?
All advice will be gratefully received - thanks!
John
GT6 vs TR6
in TR6 Forum
Posted
Manu,
I agree with the above - a GT6 is very much a 2+1/2!
Now, sacrilege time. You have a young and growing family and wish to stay faithful to the Triumph six cylinder engine. How about a Vitesse? 2 litres as standard, convertible with adequate space for the kids, saloon with plenty. There was even an estate version (very rare) to accomodate all their kit. The 2.5 engine will fit, with a Vitesse/GT6 sump hammered out to allow the extra big end throw, and the Rotaflex suspension was a good effort at curing the tuck-under of the swing axle.
And the TSSC is just as friendly as the TRR!
John