Electric fuel pump

[ian thomson]

Interesting thread on SU pumps. I agree with Norman, and others, when he says: The SU electric pump is very reliable if maintained. The points

>need cleaning and adjusting every couple of years, just as the points

>in a distributor do. It’s lack of this maintenance that cause failure.

The distinction between electric and electronic is a useful one here.  I am sure all will agree that simpler is better as in most instances the fewer parts there are to go wrong the more reliable something is likely to be. Thus an electric device, like the original SU pumps, is liable to be more reliable as it has fewer parts.  The addition of electronic components to improve the switching arrangements is likely then to add to the unreliability.  This is true up to a point.  Taking the load off the points is always likely to be a good thing.  The problem with the points, however, lies not so much with their ability to handle the operating current as the much higher back EMF generated when they open.  This can be more or less sorted by the use of a Transil or similar device which modern technology has gifted us.  Indeed SU went part way down this route on later pumps when, using existing technology, they installed a capacitor under the top cover.  Modern electronic components are very reliable if properly engineered into a device.  Unfortunately when they do fail they fail suddenly, unlike more agricultural parts like points.  All the tapping in the world will not revive them.  So I will stick with the original ( with the addition of a Transil) and thus have a chance of getting home without the embarrassment which is often wished upon us by modern technology.  While on the subject of points I notice that Mike Sherrill in his later book recommends sticking with single points.  I am still mulling this one over.  Regards Ian Notts. UK.

[jeffrey townsend]

Hi Ian, I agree - this thread is helpful. For those of us without the knowledge could someone explain what a transil does and how and where best to instal one. I m pretty sure this has been covered before so apologies for asking again.  I m currently running a Burlen replacement pump with the brass base on my TB. It has been fine for 10 years. I have several old pumps and would like to rebuild one as a spare. Could someone list what needs checking/replacing during a rebuild or point me to where I can find out. Thanks and Regards  Jeff TA1957. TB0489. Cambs UK Sent from my iPhone

On 19 Jun 2018, at 12:04, ian thomson i.thomson@talk21.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote:

  Interesting thread on SU pumps. I agree with Norman, and others, when he says: The SU electric pump is very reliable if maintained. The points >need cleaning and adjusting every couple of years, just as the points >in a distributor do. It s lack of this maintenance that cause failure. The distinction between electric and electronic is a useful one here.  I am sure all will agree that simpler is better as in most instances the fewer parts there are to go wrong the more reliable something is likely to be. Thus an electric device, like the original SU pumps, is liable to be more reliable as it has fewer parts.  The addition of electronic components to improve the switching arrangements is likely then to add to the unreliability.  This is true up to a point.  Taking the load off the points is always likely to be a good thing.  The problem with the points, however, lies not so much with their ability to handle the operating current as the much higher back EMF generated when they open.  This can be more or less sorted by the use of a Transil or similar device which modern technology has gifted us.  Indeed SU went part way down this route on later pumps when, using existing technology, they installed a capacitor under the top cover.  Modern electronic components are very reliable if properly engineered into a device.  Unfortunately when they do fail they fail suddenly, unlike more agricultural parts like points.  All the tapping in the world will not revive them.  So I will stick with the original ( with the addition of a Transil) and thus have a chance of getting home without the embarrassment which is often wished upon us by modern technology.  While on the subject of points I notice that Mike Sherrill in his later book recommends sticking with single points.  I am still mulling this one over.  Regards Ian Notts. UK.

[Peter Cole]

Ian, I think Mike speaks of this from his experience in a former life as a telecoms engineer. He mentions spending ages attempting to adjust twin contact relays to close at the same instant to share the load. It's almost impossible, so you might as well stick with single contacts. Single or double contacts the important things, as you say, is to fit a Transil to prevent the contacts from arcing as they open due to the energy stored in the coil. I first introduced these for this application in the 1980s as Mike acknowledges in his latest book. I offered the solution to Burlen Fuel Systems at that time but they refused to accept the benefits. I see now they have copied the idea and are supplying Transils with their latest pump repair kits. Unfortunately the type they have selected is too large to fit easily under the pump cap! The correct Transil is available from the MG Octagon Car Club, their part number SSU 048A. RegardsPeter

On Tue, 19 Jun 2018 at 11:50, ian thomson i.thomson@talk21.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: [u][/u]

Interesting thread on SU pumps. I agree with Norman, and others, when he says: The SU electric pump is very reliable if maintained. The points >need cleaning and adjusting every couple of years, just as the points >in a distributor do. It s lack of this maintenance that cause failure. The distinction between electric and electronic is a useful one here. I am sure all will agree that simpler is better as in most instances the fewer parts there are to go wrong the more reliable something is likely to be. Thus an electric device, like the original SU pumps, is liable to be more reliable as it has fewer parts. The addition of electronic components to improve the switching arrangements is likely then to add to the unreliability. This is true up to a point. Taking the load off the points is always likely to be a good thing. The problem with the points, however, lies not so much with their ability to handle the operating current as the much higher back EMF generated when they open. This can be more or less sorted by the use of a Transil or similar device which modern technology has gifted us. Indeed SU went part way down this route on later pumps when, using existing technology, they installed a capacitor under the top cover. Modern electronic components are very reliable if properly engineered into a device. Unfortunately when they do fail they fail suddenly, unlike more agricultural parts like points. All the tapping in the world will not revive them. So I will stick with the original ( with the addition of a Transil) and thus have a chance of getting home without the embarrassment which is often wished upon us by modern technology. While on the subject of points I notice that Mike Sherrill in his later book recommends sticking with single points. I am still mulling this one over. Regards Ian Notts. UK.

[MARK ROBINSON]

Jeffery, I referred to Totally T-type 2 when rebuilding mine: issues 6 and 7. Tells you most of what you need to know. And I fitted a transil as referred to by Peter and obtained via John James. Regards MarkTC4157

On Tue, 19 Jun 2018, 12:21 Peter Cole pcoleuk@gmail.com [mg-tabc], mg-tabc-noreply@yahoogroups.com> wrote: [u][/u]

Ian, I think Mike speaks of this from his experience in a former life as a telecoms engineer. He mentions spending ages attempting to adjust twin contact relays to close at the same instant to share the load. It's almost impossible, so you might as well stick with single contacts. Single or double contacts the important things, as you say, is to fit a Transil to prevent the contacts from arcing as they open due to the energy stored in the coil. I first introduced these for this application in the 1980s as Mike acknowledges in his latest book. I offered the solution to Burlen Fuel Systems at that time but they refused to accept the benefits. I see now they have copied the idea and are supplying Transils with their latest pump repair kits. Unfortunately the type they have selected is too large to fit easily under the pump cap! The correct Transil is available from the MG Octagon Car Club, their part number SSU 048A. RegardsPeter On Tue, 19 Jun 2018 at 11:50, ian thomson i.thomson@talk21.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: [u][/u]

Interesting thread on SU pumps. I agree with Norman, and others, when he says: The SU electric pump is very reliable if maintained. The points >need cleaning and adjusting every couple of years, just as the points >in a distributor do. It s lack of this maintenance that cause failure. The distinction between electric and electronic is a useful one here. I am sure all will agree that simpler is better as in most instances the fewer parts there are to go wrong the more reliable something is likely to be. Thus an electric device, like the original SU pumps, is liable to be more reliable as it has fewer parts. The addition of electronic components to improve the switching arrangements is likely then to add to the unreliability. This is true up to a point. Taking the load off the points is always likely to be a good thing. The problem with the points, however, lies not so much with their ability to handle the operating current as the much higher back EMF generated when they open. This can be more or less sorted by the use of a Transil or similar device which modern technology has gifted us. Indeed SU went part way down this route on later pumps when, using existing technology, they installed a capacitor under the top cover. Modern electronic components are very reliable if properly engineered into a device. Unfortunately when they do fail they fail suddenly, unlike more agricultural parts like points. All the tapping in the world will not revive them. So I will stick with the original ( with the addition of a Transil) and thus have a chance of getting home without the embarrassment which is often wished upon us by modern technology. While on the subject of points I notice that Mike Sherrill in his later book recommends sticking with single points. I am still mulling this one over. Regards Ian Notts. UK.

[ian thomson]

Mark.  A Transil is like two diodes back to back with a threshold voltage under which they are open circuit and as this is above 12v doesn't interfere with the normal operation of the points.  They go to short circuit very (very, very) quickly when the points open when a much higher voltage is created by the collapse of the magnetic field in the magnetic coil which operates the pump diaghram.  It is the sparking caused by this energy release which burns the points and is diverted through the Transil to save them.  Previous attempts to cope with this were dependent on the state of technology at the time.  Capacitors went part of the way but were relatively slow to respond.  Voltage dependent resistors increased resistance when the voltage increased but as well a being slow could be a little too large to fit under the cap. Diodes could, and have been, be used but must be fitted the correct way round.  Transils can be fitted either way round and with modern technology respond almost instantly to give a near short circuit to divert the spark current. Pete.  I understand the problem of adjusting twin points to adequately share the current but never really believed that they really operated like that.  I expect there must be some degree of sharing but my mind it is little more than marketing hype.  Where they will work, however, is in extending the life of the points as having two allows one to stop working while the pump continues operating on the other.  This in turn gives a knowledgeable owner time to check them before being stranded but in these days of fit and forget will eventually lead to complete failure.  Correctly engineered electronic "points" are better in this regard but with the caveat that when they fail you are calling the roadside assistance company, or fitting a spare pump with all the time, inconvenience and possible danger, depending on where the failure occurs.  It's easier to tap it but it does demand a degree of knowledge which people are ever more reluctant to engage with nowadays. Ian From: Mark Robinson Sent: Tuesday 19 June 12:28 Subject: Re: [mg-tabc] Electric fuel pump To: Peter Cole Cc: ian, MG-TABC List Jeffery, I referred to Totally T-type 2 when rebuilding mine: issues 6 and 7. Tells you most of what you need to know. And I fitted a transil as referred to by Peter and obtained via John James. Regards  Mark TC4157

On Tue, 19 Jun 2018, 12:21 Peter Cole pcoleuk@gmail.com [mg-tabc], mg-tabc-noreply@yahoogroups.com> wrote:   Ian, I think Mike speaks of this from his experience in a former life as a telecoms engineer.  He mentions spending ages attempting to adjust twin contact relays to close at the same instant to share the load.  It's almost impossible, so you might as well stick with single contacts.  Single or double contacts the important things, as you say, is to fit a Transil to prevent the contacts from arcing as they open due to the energy stored in the coil.  I first introduced these for this application in the 1980s as Mike acknowledges in his latest book.  I offered the solution to Burlen Fuel Systems at that time but they refused to accept the benefits.  I see now they have copied the idea and are supplying Transils with their latest pump repair kits.  Unfortunately the type they have selected is too large to fit easily under the pump cap!   The correct Transil is available from the MG Octagon Car Club, their part number SSU 048A. Regards Peter

[Norman Verona]

Peter, Isn't that what the condenser in the distributor does?

On Jun 19, 2018, at 12:21, "Peter Cole pcoleuk@gmail.com [mg-tabc]" mg-tabc-noreply@yahoogroups.com> wrote:   Ian, I think Mike speaks of this from his experience in a former life as a telecoms engineer.  He mentions spending ages attempting to adjust twin contact relays to close at the same instant to share the load.  It's almost impossible, so you might as well stick with single contacts.  Single or double contacts the important things, as you say, is to fit a Transil to prevent the contacts from arcing as they open due to the energy stored in the coil.  I first introduced these for this application in the 1980s as Mike acknowledges in his latest book.  I offered the solution to Burlen Fuel Systems at that time but they refused to accept the benefits.  I see now they have copied the idea and are supplying Transils with their latest pump repair kits.  Unfortunately the type they have selected is too large to fit easily under the pump cap!   The correct Transil is available from the MG Octagon Car Club, their part number SSU 048A. Regards Peter    On Tue, 19 Jun 2018 at 11:50, ian thomson i.thomson@talk21.com [mg-tabc] < mg-tabc-noreply@yahoogroups.com> wrote: [u][/u]   Interesting thread on SU pumps. I agree with Norman, and others, when he says: The SU electric pump is very reliable if maintained. The points >need cleaning and adjusting every couple of years, just as the points >in a distributor do. It s lack of this maintenance that cause failure. The distinction between electric and electronic is a useful one here.  I am sure all will agree that simpler is better as in most instances the fewer parts there are to go wrong the more reliable something is likely to be. Thus an electric device, like the original SU pumps, is liable to be more reliable as it has fewer parts.  The addition of electronic components to improve the switching arrangements is likely then to add to the unreliability.  This is true up to a point.  Taking the load off the points is always likely to be a good thing.  The problem with the points, however, lies not so much with their ability to handle the operating current as the much higher back EMF generated when they open.  This can be more or less sorted by the use of a Transil or similar device which modern technology has gifted us.  Indeed SU went part way down this route on later pumps when, using existing technology, they installed a capacitor under the top cover.  Modern electronic components are very reliable if properly engineered into a device.  Unfortunately when they do fail they fail suddenly, unlike more agricultural parts like points.  All the tapping in the world will not revive them.  So I will stick with the original ( with the addition of a Transil) and thus have a chance of getting home without the embarrassment which is often wished upon us by modern technology.  While on the subject of points I notice that Mike Sherrill in his later book recommends sticking with single points.  I am still mulling this one over.  Regards Ian Notts. UK.

[jeffrey townsend]

Hi,

Thanks to all who replied about transils and pump rebuilds. This list certainly works!

I'll check to see what old pumps I have and then look at getting one rebuilt - with a transil!

Thanks again,

Jeff

[b]From:[/b] mg-tabc@yahoogroups.com mg-tabc@yahoogroups.com> on behalf of Mark Robinson 58eldoradoseville@gmail.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> [b]Sent:[/b] 19 June 2018 12:28 [b]To:[/b] Peter Cole [b]Cc:[/b] ian; MG-TABC List [b]Subject:[/b] Re: [mg-tabc] Electric fuel pump     Jeffery, I referred to Totally T-type 2 when rebuilding mine: issues 6 and 7. Tells you most of what you need to know. And I fitted a transil as referred to by Peter and obtained via John James. Regards  Mark TC4157 On Tue, 19 Jun 2018, 12:21 Peter Cole pcoleuk@gmail.com [mg-tabc], mg-tabc-noreply@yahoogroups.com> wrote:

[u][/u]   Ian, I think Mike speaks of this from his experience in a former life as a telecoms engineer.  He mentions spending ages attempting to adjust twin contact relays to close at the same instant to share the load.  It's almost impossible, so you might as well stick with single contacts.  Single or double contacts the important things, as you say, is to fit a Transil to prevent the contacts from arcing as they open due to the energy stored in the coil.  I first introduced these for this application in the 1980s as Mike acknowledges in his latest book.  I offered the solution to Burlen Fuel Systems at that time but they refused to accept the benefits.  I see now they have copied the idea and are supplying Transils with their latest pump repair kits.  Unfortunately the type they have selected is too large to fit easily under the pump cap!   The correct Transil is available from the MG Octagon Car Club, their part number SSU 048A. Regards Peter    On Tue, 19 Jun 2018 at 11:50, ian thomson i.thomson@talk21.com [mg-tabc] mg-tabc-noreply@yahoogroups.com> wrote: [u][/u]   Interesting thread on SU pumps. I agree with Norman, and others, when he says: The SU electric pump is very reliable if maintained. The points >need cleaning and adjusting every couple of years, just as the points >in a distributor do. It s lack of this maintenance that cause failure. The distinction between electric and electronic is a useful one here.  I am sure all will agree that simpler is better as in most instances the fewer parts there are to go wrong the more reliable something is likely to be. Thus an electric device, like the original SU pumps, is liable to be more reliable as it has fewer parts.  The addition of electronic components to improve the switching arrangements is likely then to add to the unreliability.  This is true up to a point.  Taking the load off the points is always likely to be a good thing.  The problem with the points, however, lies not so much with their ability to handle the operating current as the much higher back EMF generated when they open.  This can be more or less sorted by the use of a Transil or similar device which modern technology has gifted us.  Indeed SU went part way down this route on later pumps when, using existing technology, they installed a capacitor under the top cover.  Modern electronic components are very reliable if properly engineered into a device.  Unfortunately when they do fail they fail suddenly, unlike more agricultural parts like points.  All the tapping in the world will not revive them.  So I will stick with the original ( with the addition of a Transil) and thus have a chance of getting home without the embarrassment which is often wished upon us by modern technology.  While on the subject of points I notice that Mike Sherrill in his later book recommends sticking with single points.  I am still mulling this one over.  Regards Ian Notts. UK.