Fuelling, carbs, petrol pump

[MarkieB]

so it looks as though it could simply be that it's a bit cold for the vaporiser, so the engine won't start on Lpg; while the petrol pump is basically a pile of rust.

However my diagnosis that the petrol pump needs replacing is based on the fact that when I disconnected the fuel inlet from the carb, then switched to petrol, turned the key to ignition, listened to the petrol pump clicking, there was no sign of petrol at all from the open fitting.

It looks to me as though there's no overflow tube from the carbs, so would I be right in thinking that the various fittings on the inlet tubes include pressure valves, or would there be a pressure valve linked to what looks as though it's a solenoid valve giving the lpg switch control of petrol input?

Now the fuel pump stopped after maybe 20 sec — although it's gone silent before so I suppose it's not a fuse — it wouldn't know the tube isn't connected to the carb, would it, so as a safety measure it stops pumping? There's no sign of a sensor close to the carb, although what I think is a solenoid could be.

after I had sprayed copious amounts of carb cleaner onto the carbs, then partly reassembled them, it fired up briefly, without the lpg rings attached, makes me think it's fuelling rather than ignition now that I've improved the ignition side.

as an aside, does anybody know whether rtc3186 is the right oil filter for a 1972 V8? I ordered it from craddocks whose page says it is for rr 1970-76, [paddocks seem to agree] although whatever they've sent me looks very similar to a standard filter [i get the impression most of the later filters, for the various engines, are very similar]; it doesn't fit on the spindle of my engine; Mine is longer/ maybe a touch thinner, the filter they've sent looks similar shape to the 12J n/a d oil filter..

[Diff]

Hi Markie,

When switched to petrol, there should be fuel flow at the carbs. However, if the fuel shut off solenoid in the petrol line(stops the petrol when on lpg) is not opening due to a fault, then the petrol will not flow to the carbs. Try checking for petrol flow from the tank/pump by disconecting the petrol line on the tank/pump side of the fuel shut off solenoid. If it flows ok, then the fuel shut off solenoid is at fault.

I don't know what gas system you have got, but most mixer systems will start even in the coldest weather providing you 'prime' the system first. The procedure for most systems in cold weather is to turn on the ignition until the red lights are lit(don't try starting), wait 3 seconds or until you hear a click from under the bonnet(relay shutting). Repeat 2 or 3 more times, THEN start.

What you are doing is priming the intake system with extra lpg(because there is no choke) to make it easier to start when cold.

Hope this helps,

Regards, Diff

[imspanners]

I may be wrong, but if it's the old style fuel pump, it has an internal pressure shut off switch. This works by opening a set of points on top of the pump. Remove the pump, and take off the top cover. You'll see the points, clean with wet&dry and refit.

[02GF74]

as an aside, does anybody know whether rtc3186 is the right oil filter for a 1972 V8? I ordered it from craddocks whose page says it is for rr 1970-76, [paddocks seem to agree] although whatever they've sent me looks very similar to a standard filter [i get the impression most of the later filters, for the various engines, are very similar]; it doesn't fit on the spindle of my engine; Mine is longer/ maybe a touch thinner, the filter they've sent looks similar shape to the 12J n/a d oil filter..

Hello, my name is MarkieB, my engine won't start but I won't tell you what engine I have nor what carbs are fitted etc etc ..

Is it a Range Rover engine? Some of the early RR used P6 engine and these have a different oil filter thread. P6 is 13/16 UNF whereas SD1 and later RR are 3/4 UNF.

you can fit a variety of different sized filters i.e. different diameter/length. I'd recommend you get down to halfodrds and look at their filters; some of them are stamped with the thread size.

Champion oil filters

====================

C105 95 mm dia; 130 long; Range Rover

Halfords oil filters

====================

HOF 206 75 mm dia; 110 long (Audi/Volkswagen) for RR

HOF 249 95 mm dia; ? long (shorter version of C105) for RR

HOF 208 short filter for P6

[MarkieB]

cheers guys,

Hi Diff, I have tried priming the Lpg, I had got worried that I was perhaps overdoing it, it needs a leaner mixture? Although I'll give it another go. As you say, worth checking the solenoid before ordering a new pump.

spanners, cheers for the pointer, I'll try to do that without it dissolving into rust flakes in my hands

02GF, there should hopefully be a clue in my sig, 1972 rangie, as far as I know it's all original, Zenith carbs etcetera; I put the engine number 392889 in the craddocks ordering system although perhaps they didn't check it. I suppose it's possible that they mistakenly ignored that then assumed it was for the other vehicle, although they would have had to have been referring to stored details rather than the specific details that went with the order.

the details <—— should suggest a reason it's a bit of a journey from the French Alps to Halfords, too! Although there's a chance of locating an appropriate alternative at a more local auto store, such as the champion filter; I'll try, though most charts I see here tend not to bother listing 1972 vehicles. The engine spindle is quite a bit narrower than the hole in the filter I was sent, possibly as much as ¼" less diameter, it slides on without touching the sides. The oil filter wrench I've got is good though, lucky I didn't attack it with a screwdriver!

[Diff]

LPG is harder to light in the cylinders than petrol, so unless you have a really good ignition system, you might want to try closing your plug gaps. When it is very cold, your battery will not be able to discharge as much power when starting, and the starter will take a lot more power from the battery when starting in the cold, so it may be that there is not enough spark voltage generated by the coil to jump the spark plug gap in an LPG mix, though it is possible for it to do so under the same conditions with petrol.

If you arent already using NGK plugs, I would recommend them. If you have a standard ignition system. I would gap them at 0.6mm for use with LPG, and see how you go.

Hope you get it sorted,

Regards,

Diff

[MarkieB]

well here she is briefly cleaned up, what a beauty:

I know, the wire should be attached to the pump

On closer inspection it looks as though there's a leak in the fuel pickup, so providing I reconnect that wire, hopefully the pump is good, running dry would be the reason for its noisiness; although the way it stops could be a concern.

As for the plugs, surprisingly it looks as though I'll be needing to upgrade the toolkit to include 21mm — I have just added Magnecor leads, a new Lucas distributor cap, a new Land Rover rotor arm, so I hope it isn't that. worth checking the plugs one day though

Incidentally, is there a technique for dropping a fuel tank? I've unbolted it; it looks as though it's a bit narrow between the chassis members, not that I get much time to struggle with it for the 2½ hrs of sun in the carpark..