Sandstone Heritage Trust - News

HTN 159 - Chris Wilson Reports from Lions River - 20 November 2006 - Marshall MP6 progress

20th November 2006

With the new hitch side plates fitted the existing bracket could be modified & repaired to work with the newly made drawbar, which attaches from the belly of the tractor as did the original. After measurements have been taken holes have to be drilled in the bracket to allow for different positions of the drawbar.

Gearing up for a big step forward, with the re-uniting of engine & chassis. The “bath tub” frame is cleaned, primed & painted prior to the engine being dropped in. Note the front of the gearbox with coupling fitted, and the steering box.



The engine sub assembly suspended and painted from underneath which will make the final painting much easier. Front & rear mounting brackets are in place, and the respective bolt holes have been cleaned and where necessary re-tapped.


The combined weight of the engine & clutch housing is excessive for the average engine crane, so a tractor mounted crane was utilized, which also provided the necessary height, as the engine has to be lifted over & dropped into the frame.

The tractor is a late 60’s JD 1020 which is in good original condition. The hydraulics particularly are working well and allow for precision movements with stability.
The weight however was enough to raise the front of the tractor so that the front wheels barely touched the ground!


With the engine safely in place the assembly can continue. First on is the head, which has previously been overhauled; valves & seats have been cut and the head skimmed.
Then the cam followers, push rods, rocker assembly & case could be assembled, all of which had been laboriously sorted, assessed & repaired from a heap of parts.
Valve clearances have been set.
With the rocker cover and all the side plates, breathers, and filler fitted most of the lube system was closed. The filter assembly was fitted with a new cartridge and the by-pass repaired. A jumper hose has been fitted in place of the oil cooler.
With the engine was received a jumble of different dipsticks, so the best fitting of these was selected. The correct amount of oil, according to the manual is 3 Gallons, so this amount was put into the sump. Naturally the marks on the dipstick did not tally with the level, so it was necessary to make a new mark. However before this could be done it was necessary to crank the engine to get oil into the filter etc, which required a starter motor.


The saga of the starter began a while ago when it was discovered that the original had disappeared.
The original was a CAV which would be very hard to find. However pre-war CAV had worked very closely with Bosch, and although this arrangement came to an abrupt halt in 1939, post-war CAV designs continued to be very similar to Bosch. This meant a good chance existed of matching something up.
Firstly a mounting bracket that fitted the engine adaptor plate was found lying in a jumble of bits at the back of an auto electrical workshop. Secondly a Bosch starter was obtained that matched the bracket. This has a very similar appearance to the original. Next a new pinion with the correct number of teeth was found, the starter overhauled & fitted with a new solenoid.

The fit is close – in fact some grinding had to be done – but it works well.


Now the engine could be turned. With no injectors fitted the cranking speed was probably close to idle, and within a short period of time the test gauge registered pressure.
This was a significant event, as due to the way the engine had been stripped and parts mixed up, despite care being taken there was an element of doubt regarding un-plugged galleries etc.
The reading was +- 400 kpa, which is close to the spec for full revs – but of course the oil was cold.
There is a relief valve which can be adjusted once the engine is running.



Showing the oil filter. The head is a Marshall part as it has provision for an engine oil cooler, which was not standard on the Leyland truck engine.
This cooler sits inside the frame close to the radiator and uses cooled water from the radiator to take heat from the oil. One very similar to the original has been located, and once the go ahead has been given it can be obtained, serviced and fitted with all the associated plumbing.

Note the short hose bridging the 2 ports in the meantime.


The curse of any restoration, broken bolts! On the LHS of the engine are 2 plates that give access to the water jacket. A cylinder casting can be seen inside. Quite why Leyland made provision for this access is not clear – it may be due to a casting technicality. In any case when the engine was stripped several of the retaining bolts which had corroded fast evidently twisted off. These broken studs had to be drilled out & re-tapped – in this case to 5/16th NC – except one that had to go to the next size up.
The overhauled water pump has been tested for fit – this too was missing and it’s a relief that it fits as there can be different pumps for different applications. This one came from a scrap Leyland Comet. The fan was obtained from a Leyland Hippo – bigger engine, but fortunately same fan!
The pump will be removed, sanded & primed before final fitting.


All cooling components fitted, but another setback! The radiator was received loose, but had been cleaned & checked at sometime apparently. A major leak manifested as shown, and unfortunately subsequent pressure tests revealed a myriad of tiny leaks indicating the tubes are wafer thin. This core is of an old pattern typical of the 50’s, so is probably the original. A re-core is vital to continuing the restoration.
A general view of the RHS of the engine. The Engine type & ser number on the tappet cover matches that stamped on the block, so it is original. Marshall fitted a breather and filler on the side of the engine as can be seen, whereas the Leyland truck had a filler on top. For some unknown reason somebody removed & lost whatever was on top of this engine so a spare breather has been fitted for the time being. After research a suitable replacement will be made.

While the original generator was a CAV and the one fitted is Lucas, it very close. It has been overhauled. Fortunately the original large pulley survived. The right belt has to be matched and a tension bracket made.



Typical of the type of small stuff that has gone missing that one only discovers on assembly are the special bushes in the injector pump drive. Fortunately in this case an old block was on hand from which to harvest these and other small bits. Note the exhauster for lorry airbrakes. The Marshall doesn’t have this; there is a spacer in its place.


Now attention is turned to the fuel system. At the heart is the injector pump. The original was well worn, and the cost of the parts would have been excessive, if they could have been located in the first place. Fortunately a re-conditioned unit was located in the UK and imported.
Timing this in-line pump is quite straightforward, using the “spill” method. A convenient flap gives access to a pointer which can be aligned with the “Inj” mark on the flywheel, (no 1 on compression). At this point fuel must just start to spill out of the no 1 port.

Provision is made for fine tuning which will be carried out when the whole fuel system is in place & bled.
At the rear of the pump is the pneumatic governor, which will be connected by 2 pipes to a butterfly on the inlet manifold. This manifold was also missing, and of course differs to that found on engines with a mechanical governor, fortunately one was found and has been repaired.



Naturally all the fuel lines, fittings etc, and one of the filter assemblies were missing. New lines will be made up using the components shown here. Many of these fittings had to be made up specially.


While much mechanical work remains, it is time to look ahead to the body work.
Panels have been sandblasted where necessary, and repaired. The front grille had the remains of a fine mesh which has been replaced by quality stainless steel.

Mudguards & nose cone have been professionally repaired. Whereas I normally abhor the use of body filler, these were badly pitted from acid rain and had to be filled. This tractor stood for many years to the east of Sasol’s oil from coal plant at Secunda, which is notorious for its acidic pollution.
Here the panels are being offloaded after repair, as well as the drawbar bracket.


The fuel tank is part of an assembly comprising dash, steering support, battery holder etc. This has been thoroughly cleaned, and painted prior to fitting.
Shown here is the underside which will obviously be in-accessible once the tank is fitted.


At this stage some of the detailing can be done. Shown here are the 2 fuel filter heads.


This area will largely be concealed by the fuel tank, so it has to be painted beforehand. The drive couplings (referred to as “Layrub” couplings in the parts book) incorporate rubber bushes which are in good shape.
The circular flange in the foreground covers the mounting for a belt pulley, which this tractor never had. Inside the box behind is where the pulley dog clutch & drive gears would have been fitted.


A small job time-wise but a big visual improvement – the fuel tank assembly is craned into place.


Some further work has also been done on the Allis B – while waiting for a new water pump ex USA which was held up by a lack of stock at the supplier, the mower was checked out. Here a broken mounting arm has a new shaft welded onto it.


The mower knife assembly needed re-alignment and some blade replacement. Setting up these sickle bar mowers is frustrating & time consuming.


Eventually the new pump arrived and has been fitted.



This enabled the tinwork, fuel system & cooling system to be assembled.


Note correct position of new temperature gauge. A new neck had to made up to accomodate this.