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Just a quickie on the above, a propos of the immensely helpful input from everyone on the Club Zoom session on Tuesday. Yesterday l had a call from Jim Turnbull of Royal Kustoms (whom l have been bothering on this topic for several months now – l must be the bane of his life!). He informed me that he currently has an Allard in his workshop which has been suffering fuelling problems: he says they resolved this on discovering that the outlet from the bottom of the tank had a bore which was too narrow to allow sufficient volume of fuel through to the pump and carbs. They have fitted a larger diameter outlet junction. So l may be trying this option anon; my current tasks are fitting a relay inline to the pump, and re-checking all wiring connexions for continuity and max. voltage. Tim.
Very interesting… do you know what the bore of your outlet pipe is? My tank is currently empty and very exposed so could easily be checked to see if it’s the same. I also might still have the original outlet pipe (which was so clogged up with gunge a replacement was needed).
Not sure what the internal diameter is, Ben, because l’d already screwed the junction back into the tank – and that’s now back on the car. But l recall it as being under half a cm. I may return to that, depending on what the current road-test programme reveals! Just temporarily l’ve taken off the inline fuel filter (between the pressure regulator and the carbs) as it was looking a bit murky. I’ve for now substituted a short length of copper (yes l know, copper! – but l’m now using 97 octane) fuel pipe and have taken the Special out on a first run: 8 mls covered, and no engine-fade. But this one clear run doesn’t overcome my feelings of scepticism, tho, by any means… 😀
Good morning all. Ben, Tim. I have done a quick calculation basing an average speed of 20 mph, using fuel at 3 mpg, which i reckon would be more than adequate for heavy, prolonged accelaration or 5he equivalent of climbin a long steep hiil. I reckon your fuel pump needs to deliver 2.71 pints per minute to achieve this. There fore if you remove th fuel pipe supplying the carburettors and direct the petrol into a suitable clean empty container, then run the fuel pump for one minute exactly you can measure how much your fuel pump is supplying to the carburettors. Be careful. Fire extinguisher on hand. I once set a series 2 Landrover on fire just by flashing the points of it’s SU fuel pump. Fortuntely i had a good fire extinguisher to hand, therefore no damage.if the supply is adequate either there is something being sucked into yhe fuel tank outlet or the problem lies else where. Try changing the coil as coils overheating can cuse similar problem to fuel starvation
That’s a great idea Dave, and if there’s a blockage or detritus in the tank this would also possibly reveal itself by running a disconnected fuel pump because you’d see the flow stop or slow down.
More feedback on the fuelling problems, folks: I’ve now driven the Special 50 mls since my last mods/adjustments – 25 of those miles this morning. I even risked 8 of those on the very busy A1M – real ‘heart in mouth’ stuff. The result is good! There was no engine hesitation, spit-back or flames from the carb intakes. In theory, it’s still running-in, after the Royal Kustoms rebuild, but l couldn’t resist wellying it a little towards the end of the test. This is reassuring, since l have been more and more convinced that the problem was capacity of supply from the new Facet pump, having been able to rule out low pressure, grot in the tank, pipe bores which were too narrow or partially blocked, and electronic issues linked with the Stromberg e-destributor. What seems to have been causing low volume of fuel supply, appears to have been loose wiring at the pump (my fault!) and the need for a relay, wired between the pump and the ign. switch. The other thing is that l will stick to E5 97 octane, to be on the safe side. So l’ll take it out again for a longer test run soon. Many thanks to everyone who helped with troubleshooting suggestions – both here on the Forum and on the Club Zoom sessions – your advice has been so much appreciated. Tim.
Yes great to hear you have solved the fueling problems Tim. Its always the simple things. Keep the forum updates coming, always enjoyable to read your posts.
<p style=”text-align: center;”>Hello Tim. Before you spend time and money on the fuel tank removal and other various remedies check your fuel line back from the carburettor. If the bore of the pipe is not much less than the carburettor iintake right back to the tank then that should be fine. On both my Allards the fuel pipe comes out at the top of the tank via a special fitting held in with I think 6 set screws holding it in. If you remove this fitting you will find, if original 2 pipes going down into the tank. One pipe should be longer than the other by about an inch. The bore of these pipes is about 1/8th of an inch if my memory serves me correctly. The longer pipe used to be the reserve which was operated by the reserve switch on the dash via a solenoid in the pick up fitting or close to the tank fitting. My P1 had the remains of it present but we took the disintegrated pieces out and connected that line to the electric pusher pump, an ordinary SU pusher pump as found on Healey 3000, and Austin Westminster 3.litre. This was all a long time ago but if I remember correctly the 2 pipes joined into the main fuel line which fed into the mechanical engine operated pump and on into the carburettor. This worked well on my P1 for many years. When Roger and I did the Monte Carlo Classic Rally in 2012 we were plagued by engine misfiring problems all the way there and back, and indeed for 12 months afterwards. We got home from Monte on a various amount of cylinders, rarely 8 and suspecting fuel problems went through the lines and into the tank. We did find that the drop pipe into the fuel tank had a hole on it about 2 inches from the bottom, but couldn’t find anything else. Fortunately the reserve drop pipe was OK so the car would run on the electric pump when the fuel level went below the hole in the other pick up pipe. Anyway, in desperation to cure the car I went the electronic route and took the old points type distributor off the P1 and fitted the electronic distributor and leads from my perfectly running K1 onto the P1. Since that day the P1 has never missed a beat. I bought a new electronic distributor set up for the K1. Both cars have been fine ever since. For the record I run both cars on the Mechanical push rod operated pump all the time on the road and also when doing competion with the K1. It has been around Goodwood in about 3 seconds less than 2 minutes beating Joe Cleggs Jaguar 3.8 engined K2 by more than a second. Joe has since put a Caddillac back into his K2. The only time I have ever needed the electric pusher pump is to overcome fuel vapourisation. For these reasons I am extremely doubtful you are starving of fuel due to insufficient bore size of the fuel line. I think it is possible you may have floating debris in your tank. This gets drawn by suction to the end of the pick up pipe, stops your fuel supply, then the engine. Once the engine stops and you switch off the fuel pump the suction ceases, and the turbulence of fuel in the tank frees the pick up pipe, and off you go again until the next time. My International tractor had this problem. When I drained the tank, the outlet is at the bottom and I had to use a piece of wire to get it to drain, I fitted a tube to my workshop vacuum cleaner and sucked the rubbish out of the tank through the filler. I found the debris causing the problem was a piece of instant gasket, which of course was quite happily floating about in the fuel. Problem solved. If you are 100% sure about the distributor and plugs and points this where I would be looking now. One other simple thing to check. Make sure your carburettor gaskets are sealing. If air can get in anywhere except through the carburettor intake this will cause similar problems to fuel starvation. Easy to investigate, cheap and easy to fit new gaskets if uncertain. Dave. P S The previous owner was the naughty culprit who had sealed the fuel gauge Sender unit with instant gasket instead off cutting out a proper gasket. Mind you it had lasted well over 15 years before I had a problem.</p>
Pleased to read your problem appears cured Tim. For some reason I didn’t read your last post until I had posted my long post sorry everyone, but all good reading and I hope it may save someone else time and money.
Sorry l didn’t catch you at the end of the Zoom tonight, Dave – we were abruptly cut off! Anyway, l just thought l’d say ‘thanks’ for your ‘long post’ above. I appreciate your words of wisdom and it’s all good advice for future eventualities! Always nice to hear your anecdotes, too. Hope you’re feeling OK – you certainly sounded on form, this evening! Tim.
I have no doubt at all that threads like this will save people time and money, this stuff is gold for people like me who are bumbling along and learning as they go – so thank you everyone!
<p style=”text-align: center;”>Good morning all. I am a minimalist. The more one puts onto a car the more potentially difficult problem solving becomes. Regarding fueling an old classic car. The original mechanical pumps fitted by the manufacturers were normally adequate,as were the SU pumps that LandRover and most BMC cars of the fifties/sixties. These days parts for some of the mechanical pumps may be either hard to come by, or not suited to modern fuel. SU however are manufacturing new pumps that are compatible, reasonably priced, and simple to fit. Both my cars can run on either mechanical or the SU pusher pumps I have fitted. I don’t seem to need a pressure regulator for either car.</p>
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