• Steve Darnell
    9 January 2018 at 10:05 #52625

    I’ve filled the sump with new, clean oil but I note that the sump is considerably lower than the oil pump. Is it necessary to prime the pump (untouched for 30+ years) before attempting to start the engine and, if so, how does one do it?

    9 January 2018 at 11:06 #52626

    Hi Steve,
    It would be a good idea to prime the pump, although some do self-prime – it’s more a matter of luck if they do!
    Undo the hexagonal brass cap on top of the pump – this will give you access to the pressure relief valve cap which has a slot in it. You can undo this with a screwdriver, counting the number of turns before it pops out (so you can replace it to give the same pressure setting), followed by a longish spring. The relief valve plunger is likely to remain in the oil pump body (although they do sometimes come out with the spring). If it does, one of those telescopic tools with a small magnet on the end will remove it.
    You can then put a small funnel into the pump and gently trickle oil into it (it soon overflows so be careful). Turning the engine on the handle once or twice will assist with distributing the oil. Once you have added about a pint in this way you can put everything back together.
    Before you start the engine it is wise to remove the spark plugs and to spin it over on the starter until you see the pressure start to build on the dashboard gauge. If you don’t get any after trying several times, try priming again, but also check the pipe connections from the sump to the pump. Some pumps are difficult – one of mine is, yet it will work perfectly on a bench test!
    Hope this helps, but call me if you want to discuss further.

    Best wishes,


    Steve Darnell
    12 January 2018 at 08:10 #52631

    Roger, many thanks for that – in fact, I put about half a cup of SAE 80 gear oil in – result: happiness!
    Now to get rid of the wretched water leak from behind the water pump…. ACE jubilee clips are anything but ace! To make things worse, it’s virtually impossible to change the short hose and/or clips without removing the pump! Oh well, at least the motor runs, with NO rattles, and 40 psi warm. Speaking of warm, when’s the wretched weather going to improve? My 70 year-old fingers don’t work very well when icicles are hanging off them!

    Thanks again,


    Colin M34
    17 January 2018 at 16:46 #52635

    Hi Steve,

    if the car has not been run for long time you ought to drop the sump and clear out the sludge from the crankshaft journals. I assume your car is a speed model, in which case these are hollow. Nice clean detergent oil will loosen the deposits which will then get into the big ends and wreck them. Sorry to be depressing!

    You might even find the inspection plates on the bottom of the sum will allow you to do it without dropping the whole sump. This is a known problem with many good quality cars including Rolls 20s.

    We also encourage fitting a full-flow oil filter.

    Colin M34

    Steve Darnell
    18 January 2018 at 08:47 #52636

    Thanks Colin, Had to remove the sump for repair. Looks like it had been in collision with an immoveable object and the front right ‘foot’ had been knocked off. The resultant repair was a mix of weld, solder, filler and zinc! My nephew, who has his own foundry and machine shop, cut off the entire corner, then made and fitted a new one. The journals were spotless, and the bearings were new! Seems the previous owner had completely overhauled the engine shortly before he died…..
    There was no sludge either! Now, where do I get a full-flow filter kit, without the need for a mortgage?

    Tim Wadsworth
    22 January 2018 at 22:43 #52644

    Wessex Workshops do a very good oil filter fitting and it’s got LAGONDA cast in. If I were you I would also fit a non return valve in the oil suction pipe. Helps to get almost instant oil pressure.

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