|
Unless its a V12, why not just replace the plugs?
|
Unless its a V12, why not just replace the plugs?
Its isn't a V12. Its 0.25 of a V-12, without the V
But OTOH, WHY just replace the plugs?
I don't have any particular reason to believe there is anything wrong with the plugs.
There may not be anything wrong with the ignition system at all, IF the spark gap tester thingy is junk, though its a bit hard to see how it could be.
I've got blue sparks, just not very fat ones.
HT leads are all within spec (or just below it) for resistance.
Coil LT resistance is a bit high and erratic (1.7-2.2 ohms) but the terminal screws have quite a bit of surface rust.
HT resistance is a bit low at 18.13 Kohms (spec is 20.7-25.3).
I dunno if these deviations are big enough to bust it, but I would have thought not.
i gave the points a couple of passes with a nail file, but as far as I could see with the aged unaided optics, they werent much burnt.
Went into town to try and buy another condensor.
The parts shop guy (good name for a band?) seemed to be saying that something (written on) my old one and the one he sold me were the same, which is why he picked it.
This was probably the capacitance (0.25 microfarads) but I understand this exact value isn't critical, and if I had been able to rummage through the box myself I might have picked something else, since THIS one has an extra wire, purpose unknown (to me).
I suppose I'll just tape it up.
|
|
HT lead resistance is around 5k ohms per 12" of lead. (Obviously not for wire leads).
Coil LT resistance for a standard 12v ignition system is around 3.3 ohms
For a ballast resistor system it's 1.2 - 1.5 ohms
And for an electronic ignition system it's less than 1 ohm. It's important that you do have the correct coil for your ignition type. In all cases the resistance of the HT windings is around 7.5k ohms.
All condensers are the same without exception. Its job is to reduce the amount of current across the points. They only differ in appearance and fitting. They all work in exactly the same way, and can only fail open circuit in which case you'd have a big fat spark across the points, or short circuit when you'd have no spark at all.
It's also important you have the correct grade of spark plug. Some are resistive (marked with the letter 'R' in the number) and some are not. Make sure yours are right. Don't just simply replace the old ones like for like. The resistance or absence of it will make a difference to the plug firing voltage, as will everything else I've mentioned.
Edited by Railroad. on 06/03/2023 at 13:49
|
All condensers are the same without exception. Its job is to reduce the amount of current across the points.
All condensers are DEFINITELY NOT THE SAME! The main purpose of the condenser is to control the CR time of the decay of the electric current in the coil and hence the value of the HT voltage. This also means the spark at the contacts is reduced. If the value of the condensor is too high, the CR time will also be long, reducing the HT voltage.
|
All condensers are the same without exception. Its job is to reduce the amount of current across the points.
All condensers are DEFINITELY NOT THE SAME! The main purpose of the condenser is to control the CR time of the decay of the electric current in the coil and hence the value of the HT voltage. This also means the spark at the contacts is reduced. If the value of the condensor is too high, the CR time will also be long, reducing the HT voltage.
From the point of view from a technician they most definitely are all the same. No training course I've ever sat, and there's been many over the years, has ever said otherwise. Even if they did differ it would be by such a tiny amount it wouldn't ever be noticeable. The biggest factor to determine coil on/off rime is the dwell angle, which as we all know remains constant in a conventional ignition system. Electronic ignition systems have variable dwell which is one of the main advantages of it. Many times I've clipped any old condenser I've had in my van onto coil negative and earth to get someone home because I didn't have the right one, and not once have I ever had the slightest issue.
|
The biggest factor to determine coil on/off rime is the dwell angle
CR time has nothing to do with the dwell angle, they're completely different things. Here's a little light reading for you: tinyurl.com/ymv6db6b
|
|
|
|
It seems to be a general view that "anything that fits will work", though presumably there is an optimum capacitance value, even if it isn't very critical.
I think the guy that sold me this one was concentrating on getting the "right" capacitance, and I might be able to get one that will fit better (without the extra mystery lead) if I go for a close value, like, say 0.22 microfarads.
According to this discussion
www.jalopyjournal.com/forum/threads/points-ignitio...2
it might be possible to "tune" the capacitance value based on the points erosion pattern
"If the mound is on the positive point (moveable contact?), install a condenser of greater capacity; if the mound is on the negative point (stationary contact?), install a condenser of lesser capacity"" if one can find a suitable range of capacitances.
I doubt its the capacitor anyway.
Might be fuel but it doesn't seem helped by butane or petrol down the carb throat.
I hope I don't have to strip the carb again because I don't really have time right now, and no longer have access to suitable premises to do it in
|
It seems to be a general view that "anything that fits will work", though presumably there is an optimum capacitance value, even if it isn't very critical.
I think the guy that sold me this one was concentrating on getting the "right" capacitance, and I might be able to get one that will fit better (without the extra mystery lead) if I go for a close value, like, say 0.22 microfarads.
Its possible that the extra lead is for earthing the condenser i.e. it's not earthed through the body like most are.
|
It seems to be a general view that "anything that fits will work", though presumably there is an optimum capacitance value, even if it isn't very critical.
I think the guy that sold me this one was concentrating on getting the "right" capacitance, and I might be able to get one that will fit better (without the extra mystery lead) if I go for a close value, like, say 0.22 microfarads.
Its possible that the extra lead is for earthing the condenser i.e. it's not earthed through the body like most are.
Thanks for the suggestion, though the body is metal with a very similar mounting tab.
I did find a mention of such a lead being used for a seat-actuated safety cut-off switch on a fork-lift truck, about as obscure as you can get.
I might try hooking that lead to earth if I fit it again, (it made no apparent difference to starting) but, since I have no reason to suspect my original cap, and I spent over an hour looking for a wee dropped nut last time, I might not bother.
On the original cap I've got a reasonable-looking spark to earth from the centre HT lead when flicking the points, but still nothing from the spark-gap testing gizmo, which I have reluctantly to conclude is junk.
400NT down't drain.
Think I'll run a fuel line from a roof-top tank (its sat for 4 months with an unlockable fuel cap, and while vandalism/sabotage is a lot less likely here than in the UK, its not impossible) and maybe change the plugs.
After that it'll probably mean another dive into the carb. Don't really like the AISIN carb on this. IIRC it has a sintered metal thing in it which looks emminently cloggable, though they used them on Toyota Landcruisers.
Come back SU, All Is Forgiven
Edited by edlithgow on 08/03/2023 at 01:15
|
|
Or the old fuel could just have "gone off"
Fuel on the roof, however, didn't make any difference, though stupidly I forgot to plug the fuel return line and didn't get many goes at starting before the roof can drained back into the main tank.
Could try again but I doubt its worth it.
Looking like a carb rebuild.
|
|
|
|
|
The specs I was quoting are those given by Daihatsu for the CB23 engine. They seem to be different to yours.
in particular, Daihatsu's stated HT resistance of 20.7 - 25.3 k ohms seems hard to reconcile with
"In all cases the resistance of the HT windings is around 7.5k ohms."
Hella quote a range of 8-19K ohms for the secondary windings (which I take to be synonymous with HT) here
www.hella.com/techworld/uk/Technical/Car-electroni...#
though those aren't points systems
Re NOT simply replacing the plugs like for like, I've no immediate plans to replace the plugs at all, because I doubt they've "suddenly" failed, and I'm certain they havn't "suddenly" become the wrong type.
Re "All condensers are the same without exception" the one I just bought isn't (Century Ignition Parts # CND-209), because it has 2 leads. I gather that the capacitance of the ones in the box must have varied too.
The only other specific example of a 2-lead cap I could find was here
www.baritaliaclassics.com/catalog/product_info.php...8
"Premium quality stator ignition condenser/condensor - two-wire version. Fits most Vespa models that call for a single-wire condenser." , which I suppose would be reassuring if it made any b***** sense at all.
Italians. Whaddyagonnado?
I think I'll take them back.
Edited by edlithgow on 06/03/2023 at 14:55
|
|
|
|
|
Unless its a V12, why not just replace the plugs?
Its isn't a V12. Its 0.25 of a V-12, without the V
But OTOH, WHY just replace the plugs?
I don't have any particular reason to believe there is anything wrong with the plugs.
There may not be anything wrong with the ignition system at all, IF the spark gap tester thingy is junk, though its a bit hard to see how it could be.
I've got blue sparks at the plugs, (just not very fat ones) but nothing on the gizmo.
HT leads are all within spec (or just below it) for resistance.
Coil LT resistance is a bit high and erratic (1.7-2.2 ohms) but the terminal screws have quite a bit of surface rust.
HT resistance is a bit low at 18.13 Kohms (spec is 20.7-25.3).
I dunno if these deviations are big enough to bust it, but I would have thought not.
i gave the points a couple of passes with a nail file, but as far as I could see with the aged unaided optics, they werent much burnt.
Went into town to try and buy another condensor.
The parts shop guy (good name for a band?) seemed to be saying that something (written on) my old one and the one he sold me were the same, which is why he picked it.
This was probably the capacitance (0.25 microfarads) but I understand this exact value isn't critical, and if I had been able to rummage through the box myself I might have picked something else, since THIS one has an extra wire, purpose unknown (to me).
I suppose I'll just tape it up.
|
But OTOH, WHY just replace the plugs?
I don't have any particular reason to believe there is anything wrong with the plugs.
Just after the end of the first lockdown when I started using the Caterham again it has a small missfire-hesitency after coasting and getting back on the throttle. When I got home I checked the plugs and all 4 were exactly the same colour and in perfect condition. So I guessed it was probably the petrol since it had stood for 8 months with a couple of gallons in it (normally never stands longer than 4 months). So put half a tank of Tesco 99 in it and after using the whole lot it was still the same. Next step was to attach the laptop and add a little extra "transient fuelling" does the same as an old fashioned pump jet on a carburettor i.e. when you open the throttle you get a bit more fuel to overcome any lean mixture, made no difference.
Checked plugs again, all fine and coil pack and leads as new (the whole lot had done under 20,000 miles).
Then added a bottle of the miracle fuel system cleaner, after using 1/2 a tank no difference.
So off to the factors for a set of plugs, from experience only Motorcraft and Denso fit correctly (strangely the others I have tried - NGK and Bosch - are 1/4" too long). Could not get Platinum or Iridium locally thus had to get standard Denso ones. Fitted them and instantly the car was perfect.
So whilst they looked perfect and were well within the expected life there was an issue somewhere.
It was fine for the remainder of 2020 and all of 2021 and 2022. Since they are standard plugs they may need changing more often but at £12 for 4 (instead of about £60 for the Iridium ones) I think I can afford to do it.
|
from experience only Motorcraft and Denso fit correctly (strangely the others I have tried - NGK and Bosch - are 1/4" too long).
Good grief, that's a helluva difference and I would suspect cause considerable problems.
Since having plug problems years ago, I always put a multimeter between the top and bottom of the centre electrode of new ones and have rejected plugs that show any anomaly.
|
from experience only Motorcraft and Denso fit correctly (strangely the others I have tried - NGK and Bosch - are 1/4" too long).
Good grief, that's a helluva difference and I would suspect cause considerable problems.
Since having plug problems years ago, I always put a multimeter between the top and bottom of the centre electrode of new ones and have rejected plugs that show any anomaly.
Low voltage continuity is not required for a spark plug. Typical ignition system HT voltage will spark across a gap of at least 25mm in air at ambient pressure. Some spark plugs were manufactured with a gap of 5mm or more in the electrode assembly within the ceramic insulator and will therefore show zero continuity when measured with a multimeter. These are designated as "auxiliary gap" or "booster gap" spark plugs and they increase the spark intensity at the firing end. The performance of modern ignition systems can make such a feature unnecessary but they were commonly used with single coil and mechanical distributor ignition systems in some older applications.
|
|
|
|
But OTOH, WHY just replace the plugs?
I don't have any particular reason to believe there is anything wrong with the plugs.
Just after the end of the first lockdown when I started using the Caterham again it has a small missfire-hesitency after coasting and getting back on the throttle. When I got home I checked the plugs and all 4 were exactly the same colour and in perfect condition. So I guessed it was probably the petrol since it had stood for 8 months with a couple of gallons in it (normally never stands longer than 4 months). So put half a tank of Tesco 99 in it and after using the whole lot it was still the same. Next step was to attach the laptop and add a little extra "transient fuelling" does the same as an old fashioned pump jet on a carburettor i.e. when you open the throttle you get a bit more fuel to overcome any lean mixture, made no difference.
Checked plugs again, all fine and coil pack and leads as new (the whole lot had done under 20,000 miles).
Then added a bottle of the miracle fuel system cleaner, after using 1/2 a tank no difference.
So off to the factors for a set of plugs, from experience only Motorcraft and Denso fit correctly (strangely the others I have tried - NGK and Bosch - are 1/4" too long). Could not get Platinum or Iridium locally thus had to get standard Denso ones. Fitted them and instantly the car was perfect.
So whilst they looked perfect and were well within the expected life there was an issue somewhere.
It was fine for the remainder of 2020 and all of 2021 and 2022. Since they are standard plugs they may need changing more often but at £12 for 4 (instead of about £60 for the Iridium ones) I think I can afford to do it.
OK, plug subtleties are possible then.
OTOH I don't have "a small missfire-hesitency after coasting and getting back on the throttle", and might not be aware of it if I had, not being at one with my highly tuned racing machine.
I have a large hesitancy on pressing the starter, as in it won't start.
Its got NGK BP5ES in it. These are apparently discontinued, and have been replaced by a resistive plug, so one might assume they were resistive too, but they don't have the R code.
Since I have no electronics, and have never got around to fixing my radio, I doubt I need a resistive plug.
These plugs aren't listed for the CB20 engine in a Charade G10 (BPR5EA-L for Europe, BP5EA-L for The World, suggesting resistance was a European thing, then) or the CB23 engine in a Charade G100 (same or I think BP5EY, manual scan is hard to read) so its possible these were a "close enough" fitment (very possible in Taiwan).
However, this is a CB22 engine in a (more or less) Charade G11, so I dunno.
I have 3 "lightly used" Champion N9YC which are listed as cross-compatible with NGK BP5ES on some (but not all) websites, so I might use these for a quick static test, but without more info I wouldn't be comfortable extended running on them. At first glance, they are likely a cooler plug, so might foul more quickly, but that shouldn't cause any actual damage.
Edited by edlithgow on 08/03/2023 at 05:28
|
from experience only Motorcraft and Denso fit correctly (strangely the others I have tried - NGK and Bosch - are 1/4" too long).
Good grief, that's a helluva difference and I would suspect cause considerable problems.
Just to clarify the 1/4" was not at the threaded end (which could result in a potentially catastrophic collision between piston and plug) but at the insulator end. The plug leads on the Ford Zetec engine have end caps that seal into the cam cover to prevent the ingress of water, the extra 1/4" would mean they did not seal. If water accumulated over time round the base of the plugs it could lead to a missfire but in reality with the caps not sealing the heat form the engine would probably evaporate any water away.
But its better not the allow any water in.
OTOH I don't have "a small missfire-hesitency after coasting and getting back on the throttle", and might not be aware of it if I had, not being at one with my highly tuned racing machine.
You would be aware of the hesitancy I had, whilst small and short lasting it was obvious especially when you consider it had not been there since fitting the engine in 2008, 12 years previously.
The Caterham engine is not a highly tuned racing machine. Internally its 100% Ford standard off the production line (I bought it in a yellow crate) with certain not required external parts removed and certain Caterham specific parts added. This results in an increase from about 135 bhp to 175 bhp but unlike a highly tuned engine it will still perform strongly from 1500 rpm to 7000 rpm. It even pulls from 1500 rpm in 5th, granny could drive it.
Very different from the cross flows I had in the car previously.
|
|
|
|
|
|
|
|
