Most recent engine restoration work 2010/2011

Previous work. 2009/2008/2007/2006/2005

Fitting ancilliaries (Carburettors, ducting,magnetos etc)

Fitting and re-assembling cylinders on the crankcase.

Cleaning and painting cylinders.

Treatment of water jackets.

.Repairing no.2 cylinder.

.Restoring valve gear no.4 cylinder.

Construction of moveable engine support.

Removal of the cylinders for restoration

Two photographs showing the almost completed engine.

The image on the left shows a closeup of the inlet manifolds and the small brass devices for admitting a shot of neat fuel as circumstances dictated. The image on the right shows one of the magnetos in position. The complete igntion loom for this side is missing and will have to be manufactured using the existant one on the other side as a pattern.

The carburettors and intake manifolds have been fitted. The float chambers await their caps (newly manufactured) as the originals were missing.

In the image on the right some of the coolant tubes and the air intake to the carbs have been fitted.

Once the cylinder has settled on the crankcase bolts it is tightened down using the various spacers, retainers and circular crankcase bolt nuts shown on the left.

The six photos above show the special ring compressor used in reverse of the normal way, necessary because each cylinder had to be fitted separately into the cylinder.

The first photo above shows one of the hoist supports manufacture to fit into the plug hole and the nylon cord attached. The second photo shows the method of painting the engine number on No 1 cylinder using a mask.

Having ascertained that he cylinders would sit down on the crankcase studs with no need to adjust the pushrods, the process of re-mounting the cylinders could go ahead. A hoist was used to take the weight of the cylinder leaving hands free to manoeuvre the pistons into place.

A trial assembly was done with one of the cylinders to check that the pushrods would allow the cylinder to sit down fully on its mounting studs (as no adjustment of the rocker arm had been made this was necessary as once the cylinder was being mounted, the pushrods were captive and could only be removed by removing the whole cylinder.

The valves, springs and rocker arms were reassembled, the reverse process of their disassembly.

Each cylinder was given several coats was painted wit Semi-gloss black diluted for spraying with 90% paint and 10% ethanol which gave the required matness. The red bands which indicated an overcompressed engine (ubercomprimiert :-hence the "u" in BzIVu were then painted in gloss red of the appropriate hue.

Treatment of water jackets with anti-corrosion product.

Before commencing treatment the inlet and exhaust ports were made water-tight as was the base of the cylinder. The valve guide holes and the rocker arm supports were also blocked. After anti corrosion treatment of the water jacket, the whole cylinder will be bead blasted and then painted. Finally one of the water inlets was stoppered leaving one open for the admission of the product.

The prepared cylinder was then placed in a suitable container and the product added until the water jacket was completely full. The product was left in the jacket for 4 hours and the residual liquid was then drained off. After 48 hours to ensure complete drying, the process was repeated.................................................................................back to top

Repairing no:2 cylinder

One of the ports to the water cooling jacket was deformed and partially corroded. The first step was to heat the area until the metal became workable.

A specially made "former" was then use to obtain a circular profile. This inevitably produced some "pin-holing" in the lip of the port.

The lip was then built up using a suitable welding rod until all the pin holes were filled.

The repair was completed and the correct profile obtained ready for some careful filing to remove any rough edges. ......back to top

Restoring valve gear no:4 cylinder

After nearly 90 years, the accumulated grease and dirt is evident on the rocker arms and valve gear. It was decided not to remove the vertical rocker gear supports as this would then avoid the necessity of large scale adjustment of valve clearances when it came to re-assembly of the components.

Disassembly necessitated the fabrication of certain tools like this "drift" for removing the rocker shaft which is internally supported by two roller bearings.

In order to remove the valves and springs, it was necessary to block the movement of each valve with a piece of wood prior to compressing the spring.

Another specially fabricated tool was used to depress the spring retaining cap and free the collets thus releasing both the spring and the valve.

The photos above show the restored (all parts cleaned, re-greased and where necessary repainted...all 64 pieces for each cylinder!)valve and rocker assemblies. A = auspuff (exhaust side), E = einlass (inlet side). The component parts of the rockers were re-assembled awaiting refitting to the cylinder head.

The cylinder (devoid of its valve gear) is now prepared for rust-proofing treatment of the inner water jacket.This involves blanking off the inlet and exhaust ports, valve guides and finally the base of the cylinder ( a seal was made with some rubber sheet).

The whole is not only ready for anti-corrosion treatment of the water jacket but is also ready for the subsequent bead blasting of the exterior and ultimately repainting.

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Construction of moveable engine support