ashaughnessy

I think the chucking out oil thing is exacerbated by the standard cast pistons in a supersprint and/or worn bores, the combination allowing more gas to get past the combustion chamber and into the crank case (can any experts confirm this opinion please?). Moving to forged pistons and/or work on the bores and piston rings to improve the seal you would expect to help the situation. I don't know what pistons were used in the 1600GT spec engine - anyone? Q102 - when you rebuilt to 140bhp spec, what pistons were fitted? Anthony

LesG, as Bob Stark says - the new plumbing for the crank case breather results in zero oil loss into the catch tank on my car, even on track days. Works perfectly. Sorry I can't post pictures - I'm in the stone age as regards photo technology. However its very simple in concept - take the existing crank case breather pipe and attach it to a union that has been fixed into the cam cover via a hole you have tapped for the purpose. Then add another breather to the cam cover to vent the pressure from there. The oil spat out from the crankcase goes directly into the cam cover, while the excess pressure is let out of the cam cover but without the oil. Anthony

I had my standard supersprint rebuilt and upgraded by Dave Brookes in Crewe (the newly built engine is great, so I'd recommend him). The new engine was measured (on a rolling road) at delivering about 150bhp, compared to its previous standard spec supposedly giving 135bhp, but after 40,000 miles probably giving more like 120bhp. Anyway, it now feels a lot more powerful and on a track day is at least 20 mph faster on the straight with more to come. The upgrade involved forged pistons, 244 cam, 45 DCOE carburettors (from 40), 4 into 1 exhaust (instead of 4-2-1 rear exit) plus a variety of other internal changes so max revs is now 7200. Total cost of all this (including ALL the costs) is probably five or six thousand. When you add in a pair of new carbs (six hundred or so), new exhaust (five or six hundred), rolling road setup (a couple of hundred), plus the build, plus transporting costs to get the engine there and back, plus a variety of other bits. It all adds up, but I suspect that any price quoted for a zetec conversion would understated as well, so consider ALL the costs before you decide which way to go. Was it worth it? Not sure. Its far better on track and based on the only track day I've done so far it keeps up with R300s. However its perhaps not as good on the road. This might be partly due to it being too fast, or it could be due to it not being so relaxed - perhaps a zetec engine in a lower state of tune would be both more relaxed and more powerful. Considerable oil loss is standard behaviour if your engine breather goes straight to a catch tank. Losing a litre of oil in a hundred miles of hard driving is easy. Re-routing the breather back to the cam cover, with a secondary breather from cam cover to tank cures this. Considerable "breathing" is also standard behaviour with an old standard spec supersprint. When revving you'll see considerable quantities of blue vapour coming out not just of the breather but also the filler cap and possibly the cam cover gasket. You'll see blue vapour coming out of the bonnet louvres when driving along slowly or at a standstill. Anthony

Moving the alternator and rewiring with a new loom shouldn't be necessary - a standard alternator and loom should be fine, unless there is something drastically different about your car. First step is identify where the current drain is and restore to correct operation. Rewiring the whole car just to fix one short circuit sounds like a drastic solution! Anthony

The sealed system conversion replaces the existing filler cap (which is mounted in the thermostat housing) with a blind thermostat housing (or rather, one that doesn't have a big hole on top covered by a cap) and changes the plumbing so that there is a water tank at the "top" of the system, i.e. higher up than everything else, that has a pressurised filler cap. The current system relies on the filler cap letting water out when there is excess pressure, the water being caught in a catch tank, and sucking the water back in when the pressure reduces. However, it doesn't appear to work well in practice and the net result is constant water loss. The sealed system simply pushes the water upwards to the sealed header tank. This is only half full, so when the pressure rises, it is air that escapes from the pressurised filler cap instead of water. When the pressure reduces, it doesn't really matter what happens - either air is sucked back in or the system pressure is reduced, but no water is lost - the water level simply rises and falls instead of being spat out and failing to be sucked back in again. This has two very distinct advantages - one, you don't lose water and two, the fan switch is always covered by water. In the old system, the water level would easily drop below the level of the fan switch, which means the electric fan stops working. The new system doesn't allow this as the sealed header tank is above the fan switch level so the water level doesn't drop this low even if (somehow) a good amount of water is lost. You can buy kits to do the conversion and they're not hard to fit. I bought mine from Roger King but I think he's retired so I don't know if he still does them. A blatchat search should show a number of old posts relating to this. You still need to check the water level regularly, but you should find that you need very little topping up. Anthony

There might be a simple explanation, but 4.87 amps sounds like the right order of magnitude to drain a battery overnight (someone confirm please?). It might simply be that you didn't have a good solid connection and that as you jiggled the bunch of wires around you sometimes got a good connection (and a 4.87 reading) and sometimes a bad connection (and the 0.06 reading). If you can get a sustained 4.87 reading, this would be the source of your problem but you still need to track down the culprit. I've been thinking about this over lunch and here's my systematic way to confirm the root of your problem, based on o-level physics and ancient car electrical designs. All this does is confirm you have a current drain and uses the fact that you didn't see the ignition light come on when you turned the ignition on with a good battery. One - ensure you have a battery that is known to be reliable. Either double and triple check your new battery, or temporarily disconnect it and replace with a known reliable battery (it doesn't need to be fitted in the car, as we'll just use it for static testing). We'll assume the battery is OK, but if we don't find any other causes of your problem we can revisit this assumption. Two - disconnect the battery entirely and measure the voltage across the terminals. It should be about 12 volts. I don't know by how much it can be less than 12 volts and still be considered functioning, but I don't think its very much. Three - connect the battery up but don't turn the ignition on. A spark while connecting would (to me) suggest a current drain to be worried about - can someone confirm this? Anyway, check the voltage across the battery again once connected up. It should be unchanged. If the voltage has dropped this indicates two things to my naive mind - one, the battery is knacked. A good battery should hold its voltage when a load is applied (I'm pretty sure) and two - there is a current drain. However, a good battery shouldn't drop its voltage even if current is being taken, so assuming the voltage stays the same, go to step 4. Four - turn on the ignition but don't start the engine. Check the battery voltage again, it should still be 12 volts. Then check the voltage on the positive side of the ignition light - I think it should be 12 volts, but you could check this against the wiring diagram - any resistances in series in front of the ignition light would reduce this. Assuming my assumption is correct and the ignition light should see a full 12 volts, then you should see 12 volts when you connect your voltmeter between ignition light positive and earth. Five - still with the ignition on and the engine not running, connect the voltmeter to the ignition light negative (i.e. between ignition light negative and earth). I think you should see zero volts (but can be checked against the wiring diagram to see if there are resistances in series after the ignition light). If I'm correct and you see more than zero volts, it suggests to me that there is a load that is drawing current in series with the ignition light between the light and earth. This would be your short circuit that needs to be traced. Note that if there is a full twelve volts across the ignition light (connect voltmeter between ignition light positive and negative connections) then the ignition light should be shining brightly. We know for a fact (I think) that there is a current drain somewhere, as you have said that your full battery drained overnight while the ignition was turned off and you didn't leave the headlights on. I think its also a fact that with a battery delivering twelve volts you didn't see the ignition light shining when you turned the ignition on without starting the engine, which suggests a resistance in series with the ignition light that is draining current. I wonder if there is a short circuit in the alternator wiring somewhere? The other thing to do is to turn the ignition off and go round the car connecting your voltmeter to various wires in turn and earth to see where there is a voltage that shouldn't be. We know the immobiliser will draw current but you'd expect this to be tiny - you'd have to connect your meter (in current mode) in series between immobiliser and battery to check what current it is drawing. Anthony

OK, thanks madman, I think that's a bit clearer now. The fact that a new battery drained to completely flat overnight while the car was idle says you have a drain or short somewhere. I'm not an electrician, but it seems to me you'd have to draw quite a current to discharge a full battery in one night (are you sure it was full? When I've bought new batteries in the past I've had to fill them myself and then charge them - was your new battery absolutely full of electrolyte?) So assuming the new battery had a good charge, is it possible to attach a current meter to see what current is being drawn while the car is switched off? You'll need to attach another full battery to check this. I'd suggest you'd need something of the order of the current drawn by the headlamps to drain a full battery overnight. So I'd say the alternator and ignition light have nothing to do with this, unless they are the source of the short circuit. Certainly its nothing to do with whether the alternator is charging the battery while driving, as the battery drained while the car was idle. Again, I'm no electrician, but I suspect the ignition light should see a full 12v with the engine not running - if that's correct then there's a current drain somewhere that is using up the other 4 volts. You could work out the size of current drain using ohms law and the wattage of the ignition light, but someone will need to confirm that the ignition light should indeed be seeing 12 volts as I've suggested. I think I'd also confirm, after measuring 4 volts on the ignition light, that the battery shows 12 volts across its terminals. A short circuit that is draining the battery would also explain why the original battery was flat when you bought the car. The behaviour you describe with the original battery would be explained if it had been severely damaged by excessive flattening. It wouldn't reliably hold a charge after that. This may sound like a very silly question - have you left your headlights on??? That would certainly drain a battery overnight. Anthony

I'm still very confused - if your battery is totally flat then of course the ignition light won't come on. What's the alternator got to do with it? You say you got a new battery - is this new battery in the car? Is it the new battery that is now flat? If a brand new battery has flattened in that short space of time, what have you done in that time? Have you driven the car or left it idle? When you installed the new battery, did the ignition light come on with the engine stopped when the battery was fresh? If not, light or alternator is at fault. otherwise light and battery are OK but alternator unproven. If the battery has flattened during driving, alternator is probably at fault (though may be simply the connections that are loose). If the battery has flattened while the car is idle, then alternator is a red herring and you must look for a drain or short somewhere (which may include the alternator or may not). I think I'd like to hear your story again from the start, told in a more systematic fashion, as I'm totally confused about the sequence of events you've gone through. Anthony

There was a video (which I probably found from a blatchat link) of an Ariel Atom with an electric motor absolutely destroying a variety of supercars on a dragstrip. Extremely impressive acceleration. I'm not sure if there is any difference in the car's inertia at rest to its inertia at speed - its the same inertia. An applied torque is the same regardless. I would think the characteristics of application would be the important factor, plus the gearing. But I'm not an engineer. Anthony

That's the theory but I'm not sure it works very well in practice with a crossflow caterham. That's why I converted to a pressurised header tank system, which has been far more reliable for me. Anthony Edited by - ashaughnessy on 9 Sep 2008 14:49:30

I presume you don't have a sealed system with pressurised header tank? Jacking the car up to a great height at each end in turn is a big help in dislodging recalcitrant bubbles, especially in conjunction with giving the hoses a good squeeze at the same time. It would be useful to do this while the engine is fully hot (thermostat open) but this means you won't be able to take off the filler cap, so it might be useful to do the jacking up and squeezing several times with both hot and cold engines, topping up when cold. Anthony

If you want a precise answer you'll need to be more precise with the question. What type of 7 with what specification? Live axle or de-dion? Ital or Ford axle? Windscreen vs. aeros? Seats and trim? Wheels and tyres? etc. If you don't need a precise answer, then 400 to 450Kg. Might be easier to ask how much a particular engine and gearbox weigh and then subtract that from your particular 7. Anthony

I second Phil's advice. Where the cable attaches to the pedal, it must be allowed to rotate. On my car (1987 vintage) the cable has an eye at the pedal end. You slip the eye onto a bolt, and keep it secure with a nyloc on the bolt. You must not tighten the nyloc, but allow the eye to float on the bolt. If you tighten the nyloc, the cable will be highly stressed by being bent and it will fail within a short time by snapping at the eye. Anthony

Am I not correct in thinking that the banner battery is a wet one that needs its electrolyte levels checking? If so, have you checked them? Sounds like your original battery was in bad condition. The ignition light not coming on when the engine isn't started sounds likely to be caused by the totally flat battery. Cause of said battery flatness still needs to be determined. If the electrolyte levels were severly diminished then this would be a likely explanation of all your symptoms but you might still want to check that you don't have a short to earth somewhere that is draining it while stopped. I've no idea how much current the immobiliser will draw. If it has flattened your battery then it has indeed done what it says on the tin :-) Anthony

I have a mechanical fuel pump so can't comment directly, but the words "facet" and "failure" do seem to occur together with remarkable regularity on blatchat, together with the words "stranded while waiting for a replacement". Anthony

I've had a clutch stick (on my crossflow) at least twice, possibly thrice, after prolonged abandonment over winter. It required scary use of the starter and the brakes to free it up. Anthony

If the carburettors aren't full of fuel then I can't see how pumping the throttle will help, as I can't see that pumping the throttle will drag any fuel through the system. Surely pumping the throttle will simply take fuel out of the float chamber, opening the valve, but you need the fuel pump to be turning in order to replenish the float chamber. I think that difficult starting after prolonged lack of use is caused by lack of fuel in the carb, which can only be cured by a) fitting an electric fuel pump or b) cranking the engine to run the mechanical fuel pump until it has refilled the carburettor (or perhaps c - somehow preventing the fuel from evaporating in the first place). You can verify my theory by comparing how easy it is to start your car from cold when it has a) been just a couple of hours since it last ran (should start instantly) and b) when it has been idle for a week (should take a few turns before starting) and c) it has been idle for a month (will need continuous cranking to start). In the latter case, a booster battery will help as it will get the pump turning faster and will avoid draining the car battery. Cars with electric fuel pumps wouldn't suffer this problem, neither would cars with fuel injection (I suspect). Anthony PS: I routinely use a booster battery when starting, as I don't use my car much and it usually needs considerable cranking before it starts to catch. PPS: This is all a theory, based on observation. I'm not an engineer. Edited by - ashaughnessy on 3 Sep 2008 17:05:27

Is this idea of giving springs (clutch or suspension) a "rest" based on sound engineering principles or just old wives' tales? I can't see why a spring would need a rest from being held statically compressed or extended, though I'm not an engineer. Anthony

I presume you have weber carburettors and a mechanical fuel pump? If so, you will find it takes longer to start it if you leave it longer between runs. E.g. leave it a day and it will be fine, leave it a week and it will be harder. I've always assumed this to be caused by a linear relationship between how long it takes the mechanical pump to replenish the carburettor float chamber with fuel. I got new carburettors a while ago and found this problem considerably reduced and I put this down to more effective seals stopping the fuel evaporating, but now I've had them for a while the problem is going back towards how it used to be. This is all theory though, I can't confirm my diagnosis. Also, I'd expect a car with an electric fuel pump not to suffer in this way if my theory is correct. By the way, I don't start by using several tries of the starter - I turn the switch and keep cranking until it starts. If I know its likely to take a long time (such as when I haven't driven it for a month) I'll use a booster battery to help the situation. Once out on the road though, restarting is always instantaneous. Anthony

Possibly worth checking the bolts connecting propeller shaft to differential??? I once had a similar clunk that went away when I tightened said bolts on my live axle car (some of them weren't as tight as they should have been). Anthony

Thanks Oily. On a related topic, what would be your golden rule for use of copper grease on threads? I hope I'm not hijacking this topic too much, but this question does seem relevant and on-topic. Anthony

> Does this not cover it? No it doesn't, unless preventing oil escaping from oil filled areas is the only principle involved in the use of loctite on threads. Anthony

Oily - what's the general principle behind your advice? It would be good to know how to apply this guidance to other situations. Anthony

Neil, I've sent you an email but don't get your hopes up. Anthony

What's wrong with felt seals?