| Author | Message | ||
     Jeff Martin Frequent User Username: jeff_r_1 Post Number: 286 Registered: 07-2018 |
This pump is for a Series 3 V12 Jaguar, will it work on my Mark VI Bentley. It's the pressure that I'm concerned about. https://www.ebay.com/itm/393471751326?&ul_noapp=true&autorefresh=true | ||
| Mark Aldridge Frequent User Username: mark_aldridge Post Number: 743 Registered: 10-2008 |
Jeff check that it is overhauled for Ethanol/ Unleaded petrol. 17 years ago I had one of these leak on my XJ12 where it is boot mounted and it emptied 5 gal of petrol into the boot unknown to me Fortunately the courtesy light switch did not spark when I opened the boot . The seals had dissolved, like the one on my Austin Healey ! I now only fit Facet pumps with regulators; although the Facet on my S1 burned out last month . Mark | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 287 Registered: 07-2018 |
I would have to overhaul it with new parts, or use premium fuel with out ethanol. Facet pumps burn out because the fuel isn't clean enough _ apparently. The piston that operates the check valves is very close tolerance, so the slightest bit of dirt may affect it in a bad way. I was just over at the Jag forum discussing Facet and Hardi pumps and their reliability. I find that people that gripe about how unreliable SU pumps are, have not rebuilt or installed them properly. A bad ground or getting human DNA all over the points will cause eventual failure when electrical resistance goes up. Never had an SU pump give me problems or fail, even with the old style foil capacitor in there. I use a Varistor now. | ||
| Mark Aldridge Frequent User Username: mark_aldridge Post Number: 744 Registered: 10-2008 |
Jeff, thanks for the comment re Facet pumps. What is the general feeling about these on the Jag forum. Mark | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2465 Registered: 09-2004 |
Jeff answering your question with the running twin pump on your car. They will cope with flow well as designed but the pressure may well need to be adjusted to the carbs Floats. Have used this type of in line regulator but seem to think the ones I used had pulsation reduction built in. eBay item number:333103829562 | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 288 Registered: 07-2018 |
Thanks Patrick. I should have just went over to Burlen in the first place to look up the specs. They list the same pump for a Jag V12 as the Bentley 4.25 litre, AZX1405 30 gallons per hour. Even if it doesn't work out, I can still use the pressure regulator. 129.00$ US dollars is what I'm paying. | ||
| Ron Lewis New User Username: great48 Post Number: 8 Registered: 01-2009 |
Hi everybody. I recently reconditioned the original dual SU fuel pumps on the Mark VI (thorough clean, new diaphragms, new points assemblies, gaskets, etc.) – all work done in full accord with the Workshop Manual – both pumps worked perfectly at test and on car. However, after having done only 20 kms since the rebuild, I noticed only one pump was ticking when I started up the other day. On checking deeper, the new points set I installed was badly pitted and black (no sign of overheating at all, just excessive arc damage) which leads me to seek the help of the forum with my queries below. 1. What is the acceptable range when testing resistance of each pump’s magnetic windings? I have gone through the Mark VI W/S manual a couple of times and can’t find any specs on that. 2. How do I test the small electronic capacitor wired across the power and earth terminals inside the pump end cap? This is my prime suspect for the points failure. 3. In the event I have to replace the internal capacitor: (i) what rating is it and (ii) which way is it fitted? The previous owner changed the car to negative earth years ago (to work with a later style radio, I suspect). Would greatly appreciate any help you can offer here, please, guys. Ron Lewis | ||
| David Gore Moderator Username: david_gore Post Number: 4011 Registered: 04-2003 |
Christopher Carnley asked me to post the following on his behalf: ""Why bother with worn out old pumps, when there are new ones in Herefordshire"?"   | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 2277 Registered: 05-2012 |
Hi Ron The capacitor on my 74 Shadow that uses the SU dual pump is 0.047 uF 400v. When I reconditioned the pump, Burlen supplied a diode to use in place of the capacitor. I presume they regarded this as a better option.   Geoff | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 289 Registered: 07-2018 |
That looks more like a varistor then a diode, at any rate a diode will work to keep the points from burning, but it is polarity sensitive, depending on what kind of diode they sold you. I diode works because the current flow that causes the points to arc is blocked by the diode. Ron, if the points are burning, change out the capacitor. Make sure you have a good clean ground on the pump _ to both ends. A bad ground will make for poor current flow and cause the solenoid to run hotter then normal, this it turn causes the points to heat up and burn. | ||
| ChristopherCarnley Unregistered guest Posted From: 109.156.245.191 |
The source for the pump in my previous post is Holden Classics: https://www.holden.co.uk/ (Message approved by david_gore) | ||
| Ron Lewis New User Username: great48 Post Number: 9 Registered: 01-2009 |
Thanks very much, gents. The capacitor rating is a great help, Geoff, so will definitely change that - will discuss the varistor, diode and capacitor options with Wilson Carbs (Airport West) - they specialise in these old English fuel systems. The earth may have added to/caused the problem, too, Jeff, as there was only one earth lead attached and that went to the other (operating) pump body. Appreciate the heads-up on the elctronic units, Chris, as that is the simpler and more reliable system by far - I just may need to put that on this year's Santa's list and leave it somewhere for the wife to find easily. Ron Lewis | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 290 Registered: 07-2018 |
Here are some more pointers: If you make up a new ground wire for the other pump, solder your ends if you use those crimp style connectors and use a heat shrink, don't use the cheesy covers that come with them, the heat shrink works so much better keeping the air out. Use a bit of electrical grease when attaching the ground to the pump and the frame with star washers, so the metal bites into itself. Use enough grease so it oozes out to keep out the air. Electrical grease conducts electricity. Use resin core solder and of course make sure the frame is clean of paint and oil, even from your fingers. Clean the points with alcohol, or almost anything from any factory oil and any human DNA/salt/oil. I believe it's small critical steps like these that are overlooked why these pumps fail when people seem to have endless problems with them. I've never had one fail on me and left me stranded. | ||
| Martin Webster New User Username: martin_webster Post Number: 17 Registered: 09-2018 |
Thanks Chris, I think that I will go to Holden’s when I replace my MKVI pump rather than messing about with all this crystal set technology. ATB Martin | ||
| Jim Walters Frequent User Username: jim_walters Post Number: 346 Registered: 01-2014 |
I use Transient Voltage Suppressors (TVS)in the fuel pumps I rebuild. The number you want is 1.5KE24CA which should be available at any local electronics supply store. This is better to use IMO than a regular diode as it is not polarity sensitive. SRH8505 SRC18015 SRE22493 SRK36971 NAC-05370 www.bristolmotors.com | ||
| David Gore Moderator Username: david_gore Post Number: 4014 Registered: 04-2003 |
Martin, you have brought memories of times past for fellow contributor Christopher Carnley! He has asked me to post the following for your interest:- "I remember Uncle John (Dalton), introducing me to the idea of the crystal set with its cats whisker, originally into a galena crystal and then the later germanium one. The crystal and its wire is actually a diode rectifier. During the 60,s to amuse my friends, (who congregated around my sister !), I bought this novelty crystal set. It actually worked, but needed a long detecting aerial, so clipping it onto the plated finger stop of the old Bakelite telephone, gave a good result." This has revived a similar memory for me of getting a crystal set from my parents as a 13th birthday present which served me faithfully especially being able to go to bed at night and listen to music my parents didn't understand let alone enjoy. I later won a high school scholarship when I was 16 and I was allowed to purchase a National Panasonic 10 transistor portable radio that served me faithfully through my University and later early working career until it died after a long and well-used life. | ||
| Martin Webster New User Username: martin_webster Post Number: 18 Registered: 09-2018 |
Slight thread drift and diversion here. Thank you David and particularly Chris for sharing his early memories of crystal set technology. Jagadish Chandra Bose was the Indian physicist who originally pioneered the crystal and microwave techniques for the detection of radio waves in the 1890s. The Bose sound technology company most of us are familiar with today was founded by Amar Bose another Indian scientist who I believe was not related to Jagadish. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2467 Registered: 09-2004 |
Ah the crystal set, built mine in the late fifties early sixties was a devil to tune in so had it set for Radio Luxembourg Seem to remember the adverts one of which was Horace Grimly with the Ever Right watch. | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2468 Registered: 09-2004 |
The memory! It was in fact Horace Bachelor. | ||
| ChristopherCarnley Unregistered guest Posted From: 86.161.5.49 |
Patrick, Horaces,s oft repeated slot (15 minutes of fame)was advertising his "Famous Infra-Draw Method" of pools permutation predictions. Usually when either Dan Dare or the Ronettes were on, and then the signal faded. The D.J,s would say "And the time by my Everite Watch is...." This was the plug by (H) Harriet Samuel for her growing watch and jewellery business. The watches were good value for money,with basic Swiss lever movements, just like the ones in the Rotary models. (Message approved by david_gore) | ||
| Patrick Lockyer. Grand Master Username: pat_lockyer Post Number: 2469 Registered: 09-2004 |
Christopher that brings back memories Keynsham was the place. Ah the aerial I had best results lobbing an old armature over a monkey puzzle tree holding the wire as it unwound. | ||
| Bill Vatter Experienced User Username: bill_vatter Post Number: 144 Registered: 09-2004 |
There's more to be concerned about than arcing and erosion at the points. High voltage generated by the points opening can also result in insulation failure elsewhere. While a condenser as used by the factory will reduce arcing at the points, a condenser may actually increase the peak voltage in the pump's internal circuitry. | ||
| Jeff Martin Frequent User Username: jeff_r_1 Post Number: 293 Registered: 07-2018 |
So will a varistor or a diode that replaces the condenser be a better choice ? It should be, since none of those actually stores any voltage. The way I see it is a condenser has to release it's voltage stored with in it self from controlling the arcing from the points. It does this through the windings in the solenoid, that's where the increase comes from ? | ||
| Jim Walters Frequent User Username: jim_walters Post Number: 347 Registered: 01-2014 |
Jeff, next time you're going by stop in and I'll give you a couple diodes or TVS's, your choice. Don't use a condensor. SRH8505 SRC18015 SRE22493 NAC-05370 www.bristolmotors.com | ||
| ChristopherCarnley Unregistered guest Posted From: 86.161.5.32 |
(Message approved by david_gore) | ||
| Bill Vatter Experienced User Username: bill_vatter Post Number: 145 Registered: 09-2004 |
The voltage spike is generated by the electro magnetic solenoid. It's a coil of wire around an iron core. By its nature it has a high inductance, symbol L. When current, symbol i, is interrupted, a high voltage is generated by the colapsing magnetic field of the coil according to the formula, V= L di/dt. The quicker the current is interrupted, the higher the voltage spike. The high voltage spike causes an arc at the points, and that arc conducts electricity, which results in the current not stopping as quickly as it would if there were no arc. The condenser will absorb electrical charge, and with a condenser in the circuit it will allow current to continue to flow for a few micro seconds when the points open. That delays the stopping of current. When the condenser is fully charged, the current stops, The voltage spike then occurs, but by that time, the points have opened far enough to prevent an arc from being drawn there. So here's the reason a condenser is not the best choice: The condenser actually stops the current quicker than current would stop without it, even though the current interruption is delayed. That's because there is little or no arc at the points. As a result, the voltage spike is higher, even though the arc is supressed. THAT is why you need a condenser in the ignition system. But in the fuel pump, except for protecting the points, it makes the situation worse. A diode does it better. A diode will prevent the high voltage spike, not just protect the points when the higb voltage spike occurs. A varistor is better than a condenser, but not as good as a diode. | ||
| ChristopherCarnley Unregistered guest Posted From: 86.182.76.81 |
That depends upon whether the diode is a forward biased type or a reverse biased one. (Message approved by david_gore) | ||
| Martin.Taylor Unregistered guest Posted From: 222.152.254.62 |
Bill, I have to disagree but will explain why. When using a varistor it will only conduct above it’s set voltage where as the diode will continue to conduct the reverse until the voltage is zero (or 0.6 if you want to be precise), why is this a problem? Because it slows the collapsing of the magnetic field and will reduce the pump speed at full load. This is why elevator brake control circuits and fast counting relays are not suppressed with diodes as it can add seconds to them dropping out. (Message approved by david_gore) |
