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

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.

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.