Richard Crawley Posted May 17, 2004 Report Share Posted May 17, 2004 Newly rebuilt (after a very long time!), the 6 has been running perfectly on the old Lucas pump & after a few short trips around the locality, it was time to stretch the boundaries a bit further afield. Sunday’s trip of around 50 miles went fine, country lanes, scenery etc. etc. – perfect & she didn’t miss a beat. Today’s trip started off very well but then, after about 40 minutes, she suddenly cut out briefly a few times on overrun but kept on going with a few judicious prods of the throttle. At first, I thought it was an electrical problem but then I remembered all the stuff I have read over the years about problems with pump cavitation & carrying packets of frozen peas or ice bags on summer trips & it got me thinking! Anyway, she finally disgraced herself completely & died just 2 miles from home on a very busy multi-roundabout thingy & being around 4PM, the evening traffic was just building up; lots of toots & rude gestures (this is Essex!). I pushed it onto the grass verge, opened the boot, & heard the pump screaming like some mad banshee! I put my hand on it & almost took the skin off! After 15 minutes or so, it all cooled down &, after a few coughs, she started again & we got home OK. This has never ever, happened to me before. I’ve read all about the “phenomenon” of Lucas pump cavitation but did not pay too much attention, as I had never, personally, experienced such problems; but that was a long time ago. I’ve always been a big fan of the Lucas pump (never had reason to shun it!) but today has destroyed my confidence in the reliability of the car. It was very much hotter than yesterday (here anyway) so, I guess, that’s what caused the problem. So, is it modern fuel that causes it? Is this the fate of my good old, but in very good nick, Lucas pump? Is it time to go Bosch! but which one? Quote Link to post Share on other sites
tim_trinda Posted May 18, 2004 Report Share Posted May 18, 2004 Richard Are you using a cooling coil around the pump motor? I have never suffered this cavitation problem even when I did a 200 mile journey on that very hot August Saturday last year, so I'm not sure that you can pin it on modern fuels. One mod I have seen to get over this problem is to fit a tube around the motor body with a fan (12V computer type) on top to draw air over the motor body to keep it cool. ======== Tim Quote Link to post Share on other sites
Richard Crawley Posted May 18, 2004 Author Report Share Posted May 18, 2004 Hi Tim, I’m not using a cooling coil or any of the other Lucas pump tricks that have been suggested over the years. In the mid 70’s through mid 80’s 3 of us ran a combination of 5’s & 6’s & we never had any such problems so never resorted to any of this in the past. My pump has not changed; it’s my very well maintained original which has never let me down in the past, which is why I’m a bit puzzled to be getting these problems now! Quote Link to post Share on other sites
jonlar Posted May 18, 2004 Report Share Posted May 18, 2004 Richard, I believe that Revington market an excellent square section tube coil (I'm sure Roger Williams refer to it in one of his 5/6 books), square gives more contact than round for better conductivity, I'm reverting to Lucas from Bosch, now I've obtained a NOS Lucas pump, and will probably try the Revington coil, don't know how much it is though! Quote Link to post Share on other sites
Andy Moltu Posted May 18, 2004 Report Share Posted May 18, 2004 There is one flaw with the cooling coil theory - The coil cools the outer case which is above the pump itself not the pump which is the bit where heat really matters. It's a bit like blowing on the saucepan lid & not the sauce! Before binning the pump - just check the PRV pressure - if that's set too high even the Bosch won't cope! (Although I did have one that managed 150psi.) Quote Link to post Share on other sites
JohnC Posted May 19, 2004 Report Share Posted May 19, 2004 ...Before binning the pump - just check the PRV pressure - if that's set too high even the Bosch won't cope! (Although I did have one that managed 150psi.) Absolutely. The pump gets most of its cooling from fuel flowing through it. If the PRV is set too high, the flow is greatly reduced. Result, hot pump. Richard - do you know of anyone who can put your pump on a bench? Even the best maintained machinery gets tired, and that may be the case with your pump. It's dead easy to tell though, with the right gear - just watch the flow and current draw as you crank up the PRV on the test rig. The specs are in the Lucas manual. Good luck. John Quote Link to post Share on other sites
tfoss Posted May 19, 2004 Report Share Posted May 19, 2004 Richard, I had the same problem even with a cooling coil fitted and keeping the tank half full. In the end there is only one solution if you want to stop worrying on warm summer days, fit the Bosch conversion. I went to Revington. Problem solved and more time to worry about the next thing to go wrong. Quote Link to post Share on other sites
jonlar Posted May 19, 2004 Report Share Posted May 19, 2004 There is one flaw with the cooling coil theory - The coil cools the outer case which is above the pump itself not the pump which is the bit where heat really matters.It's a bit like blowing on the saucepan lid & not the sauce! Before binning the pump - just check the PRV pressure - if that's set too high even the Bosch won't cope! (Although I did have one that managed 150psi.) No, not a flaw, it's the mainly the heat from the heat wiper motor type innards which generates the heat which is conducted to the fuel through the metal casting, far more than the pump itself. Quote Link to post Share on other sites
Richard Crawley Posted May 19, 2004 Author Report Share Posted May 19, 2004 Thanks for the input, A couple of clues here; the main one being that I may well be running over pressure as I had to tweak the PRV (brand new exchange unit!) to actually get the car to pick up from tick over at all once hot. From previous experience I knew it must be under pressure (around 90 psi) but I adjusted it blind (about + 15 psi) as I am still waiting for my test gauge to arrive. Also intriguing was that the first 100 mile run on a full tank was faultless! I will try filling it up again & backing the PRV off ¼ turn (5 psi) but in all probability, I will take the plunge for a Bosch pump. After 18 years of contemplation, I want the bloody thing reliable for this summer & if that takes another 200 to 300 quid, well OK that’s not really significant when you look at the total cost of the resto! But what’s the best pump & configuration to use & what mods, electrical or otherwise, are required? Quote Link to post Share on other sites
Andy Moltu Posted May 20, 2004 Report Share Posted May 20, 2004 I will take the plunge for a Bosch pump. After 18 years of contemplation, I want the bloody thing reliable for this summer & if that takes another 200 to 300 quid, well OK that’s not really significant when you look at the total cost of the resto! Look here and here If you get the parts yourself make up a bracket and have a couple of high pressure pipes made up you will do it for just over £130 rather than the £2-300. Despite what some say - try the Bosch pump on its own with the Lucas filter first and you may save even more! Quote Link to post Share on other sites
tim_trinda Posted May 20, 2004 Report Share Posted May 20, 2004 Richard Because the Bosch pump takes almost twice as much current as your old Lucas pump you will have to beef up the wiring to the pump and make sure all the connections are in good order. An easy way to achieve this is to drive a relay with the old pump feed and use the relay to connect the Bosch pump to the battery (via a fuse of course). This has the added benefit of reducing the current switched by the ignition switch. At a minimum use wire with a 1sq mm cross sectional area (e.g. 32/0.2) or preferably 1.5sq mm (30/0.25). The relay should be rated at 30A (min). ======== Tim Quote Link to post Share on other sites
ushes Posted May 20, 2004 Report Share Posted May 20, 2004 I have two TR6's, one early one late. The late one I'm using now already has a Bosch pump and initially gave me problems. When I got the car it had a Bosch fuel filter just under the tank, this looks to be a throw away canister type and had push-on ends held with jubilee clips. From the filter the feed went directly into the pump that's located under the wheel arch. The car had been standing for some time resulting in the injectors constantly blocking due to the Bosch filter being full of ****. I changed the filter for an off the shelf item from Halfords that looked similar (I have the part number written down somewhere if anyone's interested). Success ! All is well now, sorted for around £8 I'm trying to sort out a similar system for the early car (currently under restoration) and think I can get away with a new pump, high pressure hose and Halfords fuel filter at a cost of less than £120. Does anyone have a part number and a retailer for the high pressure hose from pump to PRV ? Looking at the earlier thread I assume the Bosch pump without filter to be part number 0580 254 909 is this correct ? I have a motor factor locally who is a Bosch agent, who hopefully can supply a pump. Regards Steve Usher TR6 X 2 Quote Link to post Share on other sites
Richard Crawley Posted May 20, 2004 Author Report Share Posted May 20, 2004 Have reduced the fuel pressure around 5psi this morning, car still seems to be running OK & throttle response still seems OK when you floor the throttle. I was unable to take the car for an extended run so don’t know if this has had any effect on the vaporisation problems I experienced on the last outing. Thanks Andy/Tim for the advice & the links, I had a look at the set up & it all looks rather simple & cheaper than I thought, I assume this mod definitely banishes fuel vaporisation in the pump for good! Quote Link to post Share on other sites
tim_trinda Posted May 20, 2004 Report Share Posted May 20, 2004 Steve Looking at the earlier thread I assume the Bosch pump without filter to be part number 0580 254 909 is this correct ? That is the correct part number, German Swedish & French Car Parts (tel: 020 8917 3801) have the pump and suitable filter ( Bosch 0 450 905 021 ) for £69.50 & £7.50 plus £7.95 P&P. They were both in stock 5 minutes ago! Prestige do a dinky little connector between the pump and the filter, click here for a picture. They also do the hose from the filter to the PRV but you might want a smaller one!! ========= Tim Quote Link to post Share on other sites
Richard Crawley Posted May 21, 2004 Author Report Share Posted May 21, 2004 There appears to be two alternatives for sitting a Bosch pump; under the n/side boot floor & inside the spare wheel well where the current PI filter unit is located. I assume the Bosch pump is designed for a harsh, external environment but it’s location, immediately behind the nearside rear wheel, concerns me a little due to the possibility of it being struck by largish objects thrown up from the road. If sited inside the spare wheel well, I assume that the spare will still actually fit alongside! Does anybody have any comments based on experience of either location? One final question, is the Bosch pump as noisy as the old Lucas pump? Quote Link to post Share on other sites
barnaclebill Posted May 21, 2004 Report Share Posted May 21, 2004 Malcolm at Prestige recommends mounting the pump directly under the fuel tank, boot LHS, for the best fuel flow. Mine is there, doesn`t smell and is very quiet. My old Wheel arch mounted, single barrel Bosch pump used to howl, particularly when fuel contents in the tank got Low. Go for Bosch, boot mounted [and fix a relay in the wiring so you can isloate it from a secret switch. No one can nick your car then!!!] Quote Link to post Share on other sites
Tony.C Posted May 21, 2004 Report Share Posted May 21, 2004 Richard, I also (this week) experienced a situation where my fuel pump seemed to supply an inadequate pressure to work the injectors (engine fading out - no misfire). In short I petered to a halt on the M25 (fortunately on the J4 roundabout). Weather quite warm etc, just come up the M20 ca.80 mph cruise so thought might be overheating. I have a Lucas pump with cooling coil, pump body was too hot to hold so I thought it needed to cool. Cutting a long story short I eliminated ignition problems and concluded the pump had given up & got "recovered". At home I dug further, the problem was eventually found in that the insulations had fractured where the wires emerge from the motor body in and just below the moulded plastic grommet. My action was to re-wire and thereby eliminate the partial short curcuit and all is restored.!! Trouble is I now have to replace the spindle seal as it didn't like getting disturbed. Might be worth checking before you dump the old lucas pump ? Best Regards Tony. C Quote Link to post Share on other sites
Richard Crawley Posted May 21, 2004 Author Report Share Posted May 21, 2004 Bill? I assume this is as the Prestige pic? does your spare wheel fit without any probs? I originally had a hidden cut out switch wired into the pump circuit, this got binned when I reconstructed the original loom but I intend to fit another when time allows; but I suppose this should be sooner rather than later! It was very useful &, once, actually prevented the car from being stolen; the 15 year old dumbos were even arrested as they sat there cranking the engine! Tony, thanks for that; I did recondition the pump before it went into store but I did not replace the electrical tails so this might be worth a check. I don't particularly want to dump the Lucas pump, with the additional expense & work this will involve, + it has always served me particularly well in the past. However, I just want to use the car so it’s important it’s reliable. Quote Link to post Share on other sites
badshead Posted May 21, 2004 Report Share Posted May 21, 2004 There appears to be two alternatives for sitting a Bosch pump; under the n/side boot floor & inside the spare wheel well where the current PI filter unit is located. I assume the Bosch pump is designed for a harsh, external environment but it’s location, immediately behind the nearside rear wheel, concerns me a little due to the possibility of it being struck by largish objects thrown up from the road. If sited inside the spare wheel well, I assume that the spare will still actually fit alongside! Does anybody have any comments based on experience of either location? One final question, is the Bosch pump as noisy as the old Lucas pump? Richard My Bosch pump and filter (+ glass thingy for observing nasty stuff filter has collected) are neatly fitted into spare wheel well and there's plenty of room for the spare wheel. Not particulalry quiet, but I've no idea what the Lucas sounds like. Certainly cannot hear it once engine is running. Quote Link to post Share on other sites
Kiwifrog Posted May 21, 2004 Report Share Posted May 21, 2004 I used to run a 6 with the original Lucas pump In New Zealand and the temprature in Summer there regularly used to get in the mid 30s centergrade and I never had a problem with vaporisation on long trips of 4-5 hours at high speeds. I was always on the look out for it having read all the tales of overheating fuel pumps etc. I am with Chris in that I think you should check out your pump condition and fuel pressures before splashing out on conversion kits coils coolers etc. Does your 6 not have a inertia cut out switch fitted for the fuel pump, I always used to use that to immobilise my 6 when parking. Alan Quote Link to post Share on other sites
Guest ron Posted May 21, 2004 Report Share Posted May 21, 2004 Richard Fit a pair of SUs and enjoy stress free reliable motoring. As the Honda advert says: Don't you love it when things just-------------WORK. Ron: :cool: Quote Link to post Share on other sites
jonlar Posted May 22, 2004 Report Share Posted May 22, 2004 RichardFit a pair of SUs and enjoy stress free reliable motoring. What, and be beaten away from the lights by a VW Beetle???? Quote Link to post Share on other sites
jonlar Posted May 22, 2004 Report Share Posted May 22, 2004 I originally had a hidden cut out switch wired into the pump circuit, this got binned when I reconstructed the original loom but I intend to fit another when time allows. Richard, use a good quality relay housed in the boot, supplied by heavy gauge cable (through the Inertia switch and an in-line fuse). Use the original cable to the pump to switch the relay (very little current required for switching) and incorporate a security keyed or hidden switch for anti-theft protection. Quote Link to post Share on other sites
Richard Crawley Posted May 22, 2004 Author Report Share Posted May 22, 2004 Does your 6 not have a inertia cut out switch fitted for the fuel pump, I always used to use that to immobilise my 6 when parking. Alan, Yes it does. It's also good to hear of someone else who’s run a Lucas pump without any probs. & in a hotter climate! How long ago was it? was it “proper” leaded fuel or lead replacement/lead free. Mechanically, my pump is as new & also has new brushes & seals fitted but I am definitely going to check out the electrics & running current + reset the fuel pressure properly when I eventually get my test gauge (should be next week). I still wonder if it has anything to do with modern lead free fuels being more volatile & so vaporise more easily, there has been quite a bit on this in TRaction during the last year. Quote Link to post Share on other sites
Richard Crawley Posted May 22, 2004 Author Report Share Posted May 22, 2004 RichardFit a pair of SUs and enjoy stress free reliable motoring. What, and be beaten away from the lights by a VW Beetle???? Or, god forbid, an MGB! Quote Link to post Share on other sites
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