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Post by Penguin45 on Jan 28, 2013 1:30:11 GMT
Given that Indy's Long Trip thread is going way off topic, I thought I'd better start a proper thread on the subject. Ady and I are currently investigating the 59D electronic one fitted to MG Metros with a view to putting it on the car. Might be interesting once we find out what the advance curve is. Chris. Chris I guess you have seen this site www.aseriesspares.co.uk/ignition/a-sd-electronic-distributors/4-cylinder-standard-road-electronic-distributors/59d-a-series-electronic-distributor-mg-metro-/-mini-a-block-standard-road/prod_859.htmlAs they suggest a rolling road session can help you set up the ignition does this mean the units are externally re-programmable I wonder? I don't think so, but maybe you could ask them. I assume you have access to a s/h MG Metro distributor with a dog drive? Note this unit requires a coil with a resistance of <1.5 ohms. Here is a link to some advance curves from early A series engines. www.teglerizer.com/mgstuff/advance_curves.htm - no idea how accurate it is but I know it's very difficult to get this data. There used to be a tuning guide in England , I can't remember the name, that listed the advance curves for all the popular cars maybe someone knows or has a copy. No doubt the 59D from the later A+ engines will be somewhat different to suit the emissions regs of the time and I imagine have less advance as the head flow was improved. I recall ignition timing isn't your favourite subject - just be careful, too much advance = disaster, too little = very hot engine. There are quite a few threads about the difficulties of setting up the equivalent of the mechanical weights and advance and vacuum correctly. The standard distributors were set up quite conservatively to avoid engine damage, erring on the side of too much retard. However, if you can access the program it opens the door to getting improved performance and fuel economy as long as you don't try and push it to the limit. Not sure if the MG Metro used a knock sensor to retard the ignition if necessary - I don't know if a knock sensor would actually work with all the A / B series clatter as the piezo knock sensors work like tuned microphones. Sorry if I have asked before, I'm getting old.  Your car has twin 1.5" SUs I believe. Do you have the standard 1800 cam or the MGB or 1800S version fitted and which distributor 1800Mk1, Mk11, Mk111 or "S"? It could be that if you have a mix that your car could benefit quite a lot from a programmable distributor unit to optimise the power and economy as well as compensating for the changes in fuel since the cars were designed. Regards David. Now then, to explain; I have got through three of the little red Hall Effect based ignition units which you can buy for under £30, as well as a rather expensive Petronix one since the car went back on the road. I don't like timing and have little natural aptitude for it, so I seek a reliable solution. This is not a search for some huge performance upgrade. The aftermarket units are a quick fit and easy solution, but I would suggest that they are just not reliable. It makes a great deal of sense to look for a manufacturers solution. They will, after all, have spent considerable time and money to develop a reliable system for their mass manufacturing requirements. There is a remarkable degree of cross-over and compatibility between the manufacturers because of the need to use out-sourced components - in this case, distributors. Now the logic goes like this: An A+ engine can still use a 25D dizzy, OR a 45D OR a 59D one with the electronic pack. Therefore, as the 25D and the 45D are both used on the "B" (our) engine; a 59D will physically fit and in theory, sorting the wiring should give us a runner. The link David gives to the Teglerizer site makes for a fascinating read. All Lucas dizzys fall into a very similar band as far as advance goes; and despite quite a bit of waffle, the results should be broadly acceptable. Ady is working along the lines of the Rootes/Talbot/Sunbeam distributors. These were apparently the very first electronic ignition units in mass production and are therefore massively over-engineered. There is a Bosch distributor which will apparently interchange with the Ford AC Delco and the Lucas one; therefore, changing the drive dog should allow it to fit a "B" engine. It's all very up in the air at the moment - research is continuing apace. It'll be interesting to see where we end up - I will keep you all informed. Chris. |
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Post by dave1800 on Jan 28, 2013 2:58:43 GMT
Chris Here are my thoughts: The design of the cheap < £30 devices (and some others) are IMHO fundamentally flawed for the following reasons. I have examined a trigger ring from one of these and the width of each actuating magnet extends for approximately 20 cam degrees (40 crank degrees). These magnets trigger a hall effect switch when the magnetic flux reaches a defined level which is effected by setting the gap between the ring and the sensor. Now if there is play in the distributor bearing this will vary the gap between the sensor and the ring which will result in timing jitter as the ring magnet will actuate the sensor at a different point. This jitter, I believe will be far worse than with points because the latter exert a sideways thrust on the distributor shaft which will dampen the sideways movement somewhat. The next issue is that the sensitivity of the hall switches varies with temperature. Unless these circuits are very carefully designed to compensate for this then the timing will change with temperature. This compensation adds to the complexity and cost. Another source of failure of these units I would hazard a guess is the switching transistor, typically an IGBT. They are protected against voltages known as back EMF from the coil which can reach as high as 400 volts. However, if a plug lead, king lead or any part of the HT side becomes open circuit then this back EMF can spike much higher and damage the IGBT. (So Kels spark tester is a no no and no pulling off spark plug leads!). Good units will no doubt have some additional protection but it remains a real risk with any electronic ignition unit . Finally the cost of high temperature (auto) spec components can be considerable more than the standard parts and I do question how they can be retailed at such low prices while still using the proper components. Typically the auto use components should operate up to 150C, the next grade down being 105/ 85C which I think are extremely marginal in a distributor. I would guess that many of the failures are due to thermal cycling and running cheaper components above their specified temperature levels. Now if you look at the reliable arrangements used by Bosch in the hall effect distributors used on VWs and Saabs and some other vehicles for example in the 90s. First these did not use a ring with magnets passing by a sensor. They used what is known as a hall effect vane switch. The sensor was a hall effect switch with an offset magnet permanently biasing it on (or off). The component typically used was a Siemens HZK101 150C rating. The switching was effected by 4 vanes (on a 4 cylinder car) fixed to the distributor shaft that passed between the magnet and the hall switch. This arrangement was not affected by distributor bearing play as the switching was related only to the rotation of the vane and not sideways movement that would vary a gap. The vane is also accepted as probably the most accurate means of ensuring an accurate repeatable switching point not affected by temperature. These distributors incorporated only the hall switch and vane. The coil power switching being caried out in a small external box that had its own cooling arrangements to ensure long life. Not so neat but.. Another generally reliable solution adopted by manufacturers were reluctance triggers but these are difficult to use as they are usually matched to electronics that control the dwell for a particular car and rely on an induced waveform rather than being digital. I ran my Mk1 car on a home made ignition unit. This retained the points which carried a 100ma non inductive currrent to keep them clean and fed an external switching transistor. Only about 6 components in all. Once the heel of the cam on the points had bedded in I don't think I had to make any ignition adjustments over the next 40K miles or so; the beauty of this arrangement was that I could convert back to conventional ignition at the throw of a switch. The small current through the points meant they didn't pit at all and still looked brand new. Anyone who can solder could knock one up nowadays for around £10 - there are many more sources of high voltage power transistors / IGBTs around now at a fraction of the price in real terms. Maybe I would opt for this unsophisticated but reliable and cheap solution again. Hope this is helpful and everyone hasn't fallen asleep! Regards David Given that Indy's Long Trip thread is going way off topic, I thought I'd better start a proper thread on the subject. Ady and I are currently investigating the 59D electronic one fitted to MG Metros with a view to putting it on the car. Might be interesting once we find out what the advance curve is. Chris. Chris I guess you have seen this site www.aseriesspares.co.uk/ignition/a-sd-electronic-distributors/4-cylinder-standard-road-electronic-distributors/59d-a-series-electronic-distributor-mg-metro-/-mini-a-block-standard-road/prod_859.htmlAs they suggest a rolling road session can help you set up the ignition does this mean the units are externally re-programmable I wonder? I don't think so, but maybe you could ask them. I assume you have access to a s/h MG Metro distributor with a dog drive? Note this unit requires a coil with a resistance of <1.5 ohms. Here is a link to some advance curves from early A series engines. www.teglerizer.com/mgstuff/advance_curves.htm - no idea how accurate it is but I know it's very difficult to get this data. There used to be a tuning guide in England , I can't remember the name, that listed the advance curves for all the popular cars maybe someone knows or has a copy. No doubt the 59D from the later A+ engines will be somewhat different to suit the emissions regs of the time and I imagine have less advance as the head flow was improved. I recall ignition timing isn't your favourite subject - just be careful, too much advance = disaster, too little = very hot engine. There are quite a few threads about the difficulties of setting up the equivalent of the mechanical weights and advance and vacuum correctly. The standard distributors were set up quite conservatively to avoid engine damage, erring on the side of too much retard. However, if you can access the program it opens the door to getting improved performance and fuel economy as long as you don't try and push it to the limit. Not sure if the MG Metro used a knock sensor to retard the ignition if necessary - I don't know if a knock sensor would actually work with all the A / B series clatter as the piezo knock sensors work like tuned microphones. Sorry if I have asked before, I'm getting old. Your car has twin 1.5" SUs I believe. Do you have the standard 1800 cam or the MGB or 1800S version fitted and which distributor 1800Mk1, Mk11, Mk111 or "S"? It could be that if you have a mix that your car could benefit quite a lot from a programmable distributor unit to optimise the power and economy as well as compensating for the changes in fuel since the cars were designed. Regards David. Now then, to explain; I have got through three of the little red Hall Effect based ignition units which you can buy for under £30, as well as a rather expensive Petronix one since the car went back on the road. I don't like timing and have little natural aptitude for it, so I seek a reliable solution. This is not a search for some huge performance upgrade. The aftermarket units are a quick fit and easy solution, but I would suggest that they are just not reliable. It makes a great deal of sense to look for a manufacturers solution. They will, after all, have spent considerable time and money to develop a reliable system for their mass manufacturing requirements. There is a remarkable degree of cross-over and compatibility between the manufacturers because of the need to use out-sourced components - in this case, distributors. Now the logic goes like this: An A+ engine can still use a 25D dizzy, OR a 45D OR a 59D one with the electronic pack. Therefore, as the 25D and the 45D are both used on the "B" (our) engine; a 59D will physically fit and in theory, sorting the wiring should give us a runner. The link David gives to the Teglerizer site makes for a fascinating read. All Lucas dizzys fall into a very similar band as far as advance goes; and despite quite a bit of waffle, the results should be broadly acceptable. Ady is working along the lines of the Rootes/Talbot/Sunbeam distributors. These were apparently the very first electronic ignition units in mass production and are therefore massively over-engineered. There is a Bosch distributor which will apparently interchange with the Ford AC Delco and the Lucas one; therefore, changing the drive dog should allow it to fit a "B" engine. It's all very up in the air at the moment - research is continuing apace. It'll be interesting to see where we end up - I will keep you all informed. Chris. |
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Post by dave1800 on Jan 29, 2013 2:13:37 GMT
Chris John Twist on one of his University Motors videos covers some aspects of ignition timing and he made a very simple statement that I believe cuts through all the complexities and can ensure you don't damage your engine. I'm having difficult locating it but it goes something along these lines with my bits added (he is far more succinct): The most important criteria for ignition timing is to ensure that when you are travelling fast with a heavily loaded car climbing a steep hill with your foot well down on the throttle that the total ignition timing does not exceed the maximum mechanical advance specified by the manufacturer (including the static setting). Vacuum advance will be zero under these conditions so can be ignored. Those are the conditions when the engine is at its hottest and too much advance will burn holes in pistons and worse. No one ever damaged an engine by setting the wrong ignition at idle. So, you start at the rpm where the mechanical advance is at its max and work backwards not the other way round which may be tempting. Easy - well the data available isn't that comprehensive but looking at the manuals the figures I have found are: Mk1 14 static + 20 degrees (weights) = 34 @ 3,800rpm Mk11 12 static + 26 degrees (weights) = 38 @ 4,400rpm "S" 9 static + 22 degrees (weights) = 31 @ 4,400rpm Mk111 12 static + 26 degrees (weights) = 38 @ 4,400rpm I believe the max advance for the MGB is usually quoted as 32 crankshaft degrees at 4,000rpm which ties in closely with the 1800S figure above. The other part of the equation is the vacuum advance mechanism. you will see in the manuals that they have played around with them over the years to meet emission criteria - some provide more advance and the sensitivity ie degrees v vacuum vary considerably. . However as far as I am aware all of the UK 1800s used ported vacuum, ie the take off was on the air cleaner side of the throttle which means at idle there is no advance and it starts as the throttle opens and unblocks the vacuum take off hole. The possible danger I can see wth modifying the ignition timing by taking the unit from a MG Metro is to get a mismatch betwen the electronic advance and the vacuum unit specs. In theory you could end up with too much advance at high engine speeds under moderate load if the vacuum unit still is actuating the mechanism if it is more sensitive than the original or more sensitive than required - so again I think err on the side of caution. It's very difficult to hear knock at higher RPM on these engines. 1800 vacuum units can add between 12 - 20 degrees to the advance under light load / cruising. The Mk11/111 cars start the vacuum advance as lowas 1" mercury whereas the "S" unit doesn't advance below 4" mercury, so this may be the one to use if you can find it. This sensitive vacuum unit probably accounts for a high proportion of the Mk11/111 cars quite considerable fuel consumption advantage over the "S" when driven with a light foot (sorry Alexander  . Did you know that ignition timing has a much greater impact on fuel consumption than air:fuel mixture - time for you to add timing to your wide range of skills Hope this helps you sleep Regards David |
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Post by Penguin45 on Jan 29, 2013 22:24:04 GMT
Cheers David. That's a really excellent in-depth analysis of the workings and problems associated with electronic ignitions. One thing that I have discovered in my own investigations was the sensitivity of these things to electrical noise and "spiking" on dynamo systems. A snubber (Contact suppressor) apparently solves this. HERE. It looks like things are coming together on the Rootes/Chrysler option. 45DM distributor with vacuum advance located, 1800 45D with vac located, so will be able to build the 45DM with the correct advance curve for the 1800. Matching electronic module has been found. Ady reckons he's got suitable plugs and connectors stashed in the garage from his Sunbeam/Lotus days. Just decent cap, rotor arm and ballast resistor to find, then the soldering iron can come out. Chris. |
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Post by Penguin45 on Jan 30, 2013 0:44:37 GMT
Just to add, the 1800 dizzy is a 41415 - spot on for the MkIII and Princess 1800 engine according to the STARCHAK LIST. Frustratingly, the 41716, which is the Rootes 45DM has no details on the chart - it may be quite close to the 41415. Still, one out of two is the plan. Chris. |
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Post by dave1800 on Jan 30, 2013 2:04:21 GMT
Assuming the 41716 is from a Chrysler (Hillman) Avenger or similar. First question - does it rotate the same direction (CCW); if not does it matter for the triggering? In favour of the advance curve being similar are - not a cross flow engine so maybe not too different gas flow which determines fuel burning speed and hence advance. Against - I think the bore: stroke ratio is undersquare so different characteristics. I can't recall whether it used a constant depression carb (SU/Stromberg) - if not then you are likely not to have enough advance. Note these are generalisations, each car engine has its own specific ignition requirements - note the differences on th 1800s for example. Why not speak to Martin Jay at Distributor Doctor for advice; I'm sure he can give you the best informed advice before you take the plunge. Of course if you are feeling wealthy you could go for a 123 Tune ignition and get Peter Burgess to fit it for you and set it up on the dyno. www.mgcars.org.uk/peterburgess/index.html. Note the 1800 on his MG homepage! You may also like to download the 123 ignition installation download (on their website) that gives a few examples and a description of what the ignition timing needs to do to ensure good driveability, performance and economy. Regards David Just to add, the 1800 dizzy is a 41415 - spot on for the MkIII and Princess 1800 engine according to the STARCHAK LIST. Frustratingly, the 41716, which is the Rootes 45DM has no details on the chart - it may be quite close to the 41415. Still, one out of two is the plan. Chris. |
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Post by Penguin45 on Feb 2, 2013 0:58:02 GMT
Dizzies have turned up, as have a new cap and red rotor arm. I have found that the 41716 is a CCW rotation, so will be able to re-use the action plate. The basic plan is to strip both down and fit the weights, springs and vacuum unit from the 41415 into the 41716, which should give the correct advance pattern for a MkIII/1800 Princess. The electronics appear to simply sit on top in place of the points, with a plastic shroud. I am 99.99% certain that the Gold Seal engine is a Princess unit, so it should all work out.
As I said earlier, this is not about performance, it's about reliability. The engine doesn't care where the spark is coming from, so long as it arrives on time.
I would love to play with the 123 system (Chris the painter has one on his MGB and likes it.), however, as usual, there are budgetary constraints. The twins are now 17, so one more year at home and then three years at university and I might just have some cash to spend! Providing they don't want a gap year.
Anyway, ballast resistor is en route, as is a Lucas DBL110 coil and the ignition unit itself, so perhaps some proper fun can start in a week or so. I will, of course, photograph everything. Ady's job is to go and find the connector plug.
Chris.
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Post by dave1800 on Feb 2, 2013 9:20:16 GMT
Chris
I guess new distributor weight springs would be an excellent investment to ensure the timing remains on spec and shouldn't stretch the budget.
Look forward to the photos
regards
David
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Post by Penguin45 on Feb 2, 2013 9:25:53 GMT
I guess new distributor weight springs would be an excellent investment to ensure the timing remains on spec Good point - I think Moss do them. Will investigate. and shouldn't stretch the budget. Bababa boom tish! Chris. |
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Post by dave1800 on Feb 2, 2013 11:27:11 GMT
If not, as they seem to specialise in sports car parts MGB etc, Distributor Doctor looks like a good place to try. There is some advice about fitting new springs to old distributors on this page www.distributordoctor.com/distributor_advance_springs.htmlregards David I guess new distributor weight springs would be an excellent investment to ensure the timing remains on spec Good point - I think Moss do them. Will investigate. Chris. |
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Post by Penguin45 on Feb 3, 2013 1:16:15 GMT
I forgot about Martin.......  Moss supplied a set of 5 springs for under £10. These are supposed to cover the various 25D and 45D dizzies as used by the MGB, so hopefully the right ones are in there. Looks good at a glance. Will find out properly soon. Chris. |
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Post by dave1800 on Feb 3, 2013 13:15:38 GMT
You may wish to read this - posted before but the original link no longer working. It describes the relationship between the rate of advance (eg degrees per 1000rpm) and the springs. Now all you need to know is what your engine / carb set up actually needs! www.jcna.com/library/tech/tech0015.htmlSounds like fun Regards David I forgot about Martin....... Moss supplied a set of 5 springs for under £10. These are supposed to cover the various 25D and 45D dizzies as used by the MGB, so hopefully the right ones are in there. Looks good at a glance. Will find out properly soon. Chris. |
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Post by dave1800 on Feb 8, 2013 7:38:19 GMT
I have found another alternative unit made by Aldon who have for many years supplied the "igniter" modules that fit in the distributor. This is a programmable unit that sits outside the distributor and can be triggered by a range of triggers including, if you wish, the points. You can switch between two maps so it should be good for those running dual fuels. At present there is an introductory offer which makes it look like good value. As far as reliability goes the electronics are not subjected to as much heat as inside the distributor if the box is properly positioned so that is one issue resolved. www.aldonauto.co.uk/shop/product.asp?P_ID=800David |
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Post by threelitre on Feb 8, 2013 11:19:28 GMT
That is interesting including an interesting price! My Maestro has one of the late and very good electronic Lukas distributors, but as it it running LPG there is no way to properly adjust the thing to give ideal advance at low and high rpm. Such a unit looks like the solution. Also: Using acceleration measurements and a good ear you can try to find out good (possibly close to ideal) correction values for your existing distributor with out the use of a test bed. Modern gadgets like mobile phones and GPS units come in handy here, as well as a stretch of flat, straight road with low traffic. Alexander |
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Post by Penguin45 on Feb 20, 2013 1:26:26 GMT
Alexander, you'll have the 59D dizzy on your car. There's no reason that you can't stick some petrol in for testing purposes.......... The missing ballast resistor has made it as far as Stanstead Airport, according to Fed-ex tracking. Another day or so and we'll be in business. Chris. |
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Ady and I are currently investigating the 59D electronic one fitted to MG Metros with a view to putting it on the car. Might be interesting once we find out what the advance curve is.
Chris
Your car has twin 1.5" SUs I believe. Do you have the standard 1800 cam or the MGB or 1800S version fitted and which distributor 1800Mk1, Mk11, Mk111 or "S"? It could be that if you have a mix that your car could benefit quite a lot from a programmable distributor unit to optimise the power and economy as well as compensating for the changes in fuel since the cars were designed.
. 
