Sd.Kfz 222 and 223 Ausf A – Horch V8 3.5 litre Cylinder Head - Inside Track | Renault TSF Tank Kent

Locating engines for the Ausf A le.Sp.Wg armoured cars has not been easy. The basic difference between the two V8s – for the Ausf.A has a 3.5 litre engine while the Ausf B has a 3.8 litre engine. There are many external differences between the two engines and we will cover these in due course but the main visual difference is that the Ausf A has a split head configuration - 4 cylinder heads whereas the Ausf B has the conventional 2 cylinder head set up. Why Werk Horch AG elected to use split head engines for the Ausf A Einheitsfahrgestell I is not in question for now. The issue for now is the split heads themselves. We have now located more than enough split head cylinder head covers for a second engine. Some need a little attention given the violent end to their operational life whereas others are too far gone. We considered having patterns made and casting the required split heads anew but have been fortunate to find all we require. A common problem to all is that the machined face of the cylinder head which fits to the block face is pitted. The corrosion pitting varies from one to the other but we are confident they can be machined to provide a good face to the block. If one does provide a larger problem having deeper pitting than initially observed – more of the face will have to be machined off to achieve the desired flush with the block. The angles of the split head do not readily allow for much to machined off as this will affect the angle of the fitting to the block itself. If further machining is required perhaps a slightly thicker gasket can be fitted to remedy this problem by retaining the correct angles between the split cylinder head and the block face. Looking to the split cylinder heads individually we have noticed a few differences. Condition has already been noted but there is one outlier we recently secured that is quite different upon inspection. The condition of newly arrived cylinder head is quite good and it still retains much of the original black paint used on the engine all those years ago but the hollows for the spark plug ports are more substantial than the other examples we have. The hollows are larger in diameter suggesting easier access to the sparkplugs and not a graded slope as in the case of the standard variety. The second large difference is that the ports allow for 14mm sparkplugs and not 18mm as in the standard cylinder head. See attached images to compare this cylinder head against the more common example. The remnants of the spark plugs can be seen in and out of the outlier cylinder head. The lead image is taken from the Ersatzteiliste fuer Einheitsfahrgestell I and includes the gasket in the photo. Machining out the difference to allow for an 18mm sparkplug is a possibility but may expose water gulleys within the casting. The question is which engine is this split cylinder head from? The part number cast into the cylinder head is clear to see. This does not correspond with the 3 different part numbers listed for the split cylinder heads listed for the Horch 3.5 litre V8. Does the 14mm sparkplug diameter suggest an earlier engine? Was there a civilian engine with split cylinder heads that we have not seen? All of these questions will be answered in time but will have to be addressed for this cylinder head to take its place with the 3 other good cylinder heads on the second 3.5 litre V8 Horch engine destined for the 3 Serie Sd.Kfz 223 Ausf A. .

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