A10 Oil pump failure: Does the team think?

[RESTORER]

Hi All, Having almost finished restoring my 1954 A10, it runs well enough, but won't tick over as I have not been able to sort out the carb settings (Amal 276GG/1DB). Oil does not return to the tank and the rocker box is quite dry so I have ceased work.  Before I start the strip down, can anyone identify any common faults to look for, or is there a method of priming? I can't find anything that covers this in the service sheets or on this site. I have fitted a new driving spindle and I thought that the pump felt free when I returned it to the engine.  The oil tank is full, and has been that way for a while now, and I cannot find any signs of leaks.  Any suggestions would be gratefully received.  Incidentally, since I fitted a length of shrink tube on my speedo cable, there still has not been any leaks there either, so thanks to all who contributed to that.  Thanks for reading, Restorer.

[Bess]

Hi,

Disconnect the oil pipe connection at the engine, ensure oil flow, reconnect. Fit a tube to the oil tank breather, ensure the oil cap is in place, remove the pressure relief valve complete, blow down the tube to pressurise the oil tank and wait until you see oil dripping out, replace the PRV. Using the kickstart (with plugs removed) to turn the engine over will help.

Pour 1/4 pint of oil in the inlet rocker cover to prime the engine. When the engine starts and oil returns to the oil tank place your finger over the discharge in the tank for a short while to force oil to the rockers (you will find any leaks to the rockers as well).

Best wishes..

[RESTORER]

Thanks Bess, first job for tomorrow. I'll keep you posted.

[JulianS]

It is possible for there to be an airlock in the oil feed pipe.

If priming the sump does not sort it then first loosen the feed pipe so that oil seeps out, tighten and try again.

On the rare occasion it is necessary to remove the timing cover and slacken the pump retaining nuts and wait until oil seeps from the joint surface, tighten, refix cover and try againg.

[berniej]

Worth double checking that you have the feed and return lines from the tank connected the right way round...?

Cheers,
Bernie

[RESTORER]

Hello again, The pipes are the right way, high to high-low to low, the lower one being the engine feed line as I understand them, but as you say berniej worth a re-check, so thanks.  When the engine line is disconnected, the outflow (from a full tank) looks pathetic.  The armoured pipes are new so I think the flow problem, if there is one, will be within the tank area.  Can anyone describe the expected flow at the oil feed point?  I know the filter in the tank is a fine one, but I feel that it should give more than a slow dribble, almost a drip really, so that just leaves the exit pipe inside the filter, my next job after draining before I move on to Julian's pump slackening.  Having tried Bess's PRV test, I did eventually get some drips out of the open hole but it took a lot longer than I expected, maybe due to the slow oil feed.  Thanks all.

[JulianS]

Oil supply from the pump can be reduced by a poor quality gasket.

Be certain you have a good quality gasket fitted.

In the photo the gasket on the left is the excellent SRM product.

Top right is a new old stock BSA  item.

Bottom right is a gastly pattern item with holes far too small for the safety of an engine.

[JulianS]

Also note the too large holes for studs in the bottom right gasket which allows it to be displaced increasing the chance of partially blocking the oilways.

[berniej]

From looking at the parts list I think that the tank filter/connection is the same as my B31 29-7962. If so that runs pretty freely if I disconnect the line (although my gauze may be coarser than yours - I think it's the original).

I have known poorly soldered unions to be blocked by the use of too much solder which runs into the pipe.

Cheers,
Bernie

[DAVE BRADY]

Hi,

Try blowing up the feed pipe back up in to the tank.  It may be a bit of a push but you should be able to cause bubbles in the tank. If not then there could be a blockage in the tank outlet.
Has the tank been completely cleaned out as fine sludge, like the type that gets caught in the crank, can get through the gauze and could accumulate and harden over time.
When fitting the pump ensure that it is not distorted by tightening up too much (use a short spanner to reduce the leverage or 8/10 ft.lbs on a torque wrench) and if not using the SRM gasket be sure to fit the fibre washer under the pump where there is no gasket.  This is to fill the gap and is often left out. To realise the importance of this put the pump on and do the two main studs so that they are just pressing on the gasket.  Measure the gap between the pump and the casing where the other stud goes.  The fibre washer should just slide in so that it takes up the space and ensures the pump does not distort when tightened up.  If the washer seems too thick or too thin find one that fits.

Have you checked to see if the new oil pipe is not blocked?  Pattern parts?

Dave.

[RESTORER]

Thanks for all this lads.  I feel sure that the line as far as the engine connection is clear but I have only blown it one way and will recheck all while I wait for some new gaskets to come - from SRM.  I will also post a pic of the oil filter.  My oil tank is the flat type.

[RESTORER]

As promised, here is the oil filter fitted to my machine.