Bongo Fury

HELP!
I've got a fully fitted V reg van that I've owned for 6 years - last year I was told that the head gasket had gone and the head was warped. I paid for a full engine rebuild and then had to have a fuel pump rebuilt, costing in total nearly £3,000.
I've covered less that 6,000 miles since the rebuild but earlier this year noticed oil leaking from the engine. I took it back to the garage that had rebuilt the engine and they stated that it was the inlet manifold gasket and replaced it. The engine is still leaking oil and is now spewing out big clouds of black smoke.
I've sought a second opinion and they state that the oil is leaking from the fuel injection pump to the timing case gasket. Also oil is leaking from the dipstick seal due to excessive crank case pressure - they state that the most likely cause of this is back pressure due to worn piston rings and cylinder cases. They say that this is causing the smoke and that there are no leaks at the head gasket.
The engine garage have been less than quick in arranging for the van to be looked at. My concern is that this looks like a problem that should have been sorted when the engine was rebuilt - I queried about replacing the engine at the time but was told that the rebuild was a better option.
I cannot keep throwing money at the van and don't know whether to
a) Have the engine looked at again
b) look to source a replacement engine
c) stick the van on ebay as it is and just get rid of it
I'm seriously getting fed up with this van - any suggestions what I should do please
(I should note that I bought the van originally from a dealer in Southampton I later found out that it had been put through the auctions due to a 'mechanical fault' - not sure if this is linked as I've had it so long now)

Think I would be going. Back for a nice friendly chat with the engine rebuild garage
That's not long for a rebuild did they give any time mileage guarantee when done

Do you know what the 'full engine rebuild' entailed? If it was done by a reputable company they would probably be a member of the trade federation who should be able to provide you with further assistance. Either way, they should provide a reasonable warranty.

http://www.federationofengineremanufacturers.co.uk/

There are a number of so-called engine remanufacturers who do little more than very basic servicing to engines salvaged from scrap vehicles and certainly don't go as far as replacing piston rings, bearing shells etc. Try doing some research online for the place you went to and see what other experiences people have had with them.

find a recommended garage and ask them to do a few simple tests, like a full compression test on each cylinder, check the valve stem oil seals etc.
these tests will give a good indication of how the engine is doing and what needs sorting, the cost of these isnt that expensive and may indicate that the possible faults are not too expensive to fix.

if the valves are not seated right or the stem seals leaking this could give pressure into the rocker cover and oily vapour, and oil leaking on to the back of the valves, so when opened it runs into the bores and is burnt off. the crankcase/rockercover gasses are put back into the air inlet manifold via the air filter pipe at the rear of the head then to the turbo, when this is loaded with oil it works its way round to the inlet manifold, it is now at its coolest so may condense to a liquid again and shows as a leak.
to test this look on the passenger side of the rocker cover, there is a 20mm rubber pipe half way along, remove this and look for pressure/oil.

if all else fails, trading standards

Thanks for the replies. I won't mention who the garage were at the moment but they were recommended through the Bongo Fury site - I had a six month warranty but am not really sure what was done as it just says 'engine rebuild'. A bit more research this weekend and a return chat next week I think