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Fitting an XPAW Engine

Not too well known these days is that the Wolseley 4/44, built from 1952 until mid-1956 used a version of the MG YB SC/2 engine. 31,000 were made but few survive today. Just like the Y Type, the 4/44 was purchased cheaply by T-Type owners who were wise to the engine, and used as spares. You could buy a 4/44 in the mid-1970s for a tenner, they had mostly rusted so badly they were uneconomical to repair; but their engines, gearboxes and rear axles were often only half worn. You cannot use the 4/44 gearbox in your Y Type as it is modified for column-change, but the gear clusters can be used. The rear axle is identical to the YB’s, but the wheels only have four studs, not five so you would need to swap over the bearing hubs from your old axle.


The Wolseley 4/44 was one of two brand-new, monocoque saloon cars that Nuffield Motors were about to launch on the market in 1952. The Wolseley was 2” higher than the almost identical MG Magnette ZA; this was done by spring heights and adjusting the front subframe. Originally the 4/44 was to have a single carb 1250cc XPAW engine and the Magnette a twin card version of the 1466cc XPEG. But as Austin had merged with Morris that year, the MG eventually got the new BMC 1489cc ‘B’ series engine, gearbox and rear axle and arrived in 1953. The only bit of an MG ZA that might fit your Y Type is the steering rack; everything else is ‘Austin’ based, brakes included.


XPAW in situ If you can beg, borrow, steal or even buy legally a Wolseley 4/44 engine you will soon see that a few bits will require swapping over from your old Y’s engine. You will need your inlet and exhaust manifold as that on the Wolseley is totally different (but you can use its carburetter). You will need your XPAG sump as that casting is very ‘forward’ on the 4/44 to miss the suspension cross-member. You will need your XPAG cylinder-head rear plate. That on the 4/44 has a heater pipe running from it that is impossible to fit on a Y as there is no room. You will also need the front engine plate because the 4/44 has different engine mountings. A bit of drilling is required to drill out the MG dip-stick position which is on our engine’s left; on the 4/44 it is on the right under the manifolds. This is not a vital mod as you can put up with the 4/44’s position. If you do drill the MG position you need to pull out the 4/44 tube and tap the hole to fit a blank. This tube then needs fitting to the new position. Note you must use your MG Y Type dip-stick with the MG sump, another thing to swap over.


The 4/44 has the later oil filter and a much more modern distributor. You can use your old Y Type distributor or fit the 4/44 one as this takes cheaper and more available ignition points and condenser. It will also take the MGA/MGB electronic ignition kit.


XPAW layout drawing.To swap over the sump is easy but ensure you use XPAW sump gaskets as the 4/44 ones are shorter at the front bearing area. The front plate requires the removing of the fan pulley, the timing chain cover and the camshaft chain and sprockets/chain tensioner. Once you have fitted your MG Y Type front plate, you can put all the other bits back with new gaskets of course, plus a new timing chain. I would suggest you refit your XPAG timing cover that goes with your MG sump as these use the asbestos string seal; later 4/44s used a proper neoprene lip seal and it is a machining job to your MG sump for this modification.


The XPAW already has the stronger later crankshaft and the 8” clutch. If you are fitting the 4/44 engine to a YA or YT you must decide if you are keeping your current 7.25” clutch or going over to the 8” clutch. The easiest way is to swap over the flywheels and keep your old 7.25” clutch. If you do use the later 8” clutch on the YA or YT, you will need a ‘bastard’ clutch plate that is 8” diameter but has a 7/8” centre (the 8” clutch has a 1” centre) The YA/YT has a gearbox with a smaller first-motion-shaft than the later YB has. Ian Wannocott on 01626 891645 can supply suitable clutch plate to suit. The YB already has the bigger clutch so there are no problems at the rear end when fitting.


If you have a lead-free modified head on your Y Type, it will fit easily onto the 4/44 engine because the cylinder blocks and head are identical to our Ys.


Another item the 4/44 does not use is the engine steady bar under the water pump. This little bracket requires swapping over too.


XPAW plate on the right side, the dipstick hole is plugged.So just to recap, you need to swap over the sump, front engine plate, possibly the timing chain cover, the rear head plate, possibly the distributor, the manifolds, and possibly the dip-stick position (though you can live with the 4/44 location). For YA/YT owners there is the clutch problem easily cured if you use your current flywheel, but equally fixable is you use the complete 4/44 8” clutch cover with a ‘bastard’ plate with a smaller 7/8 centre.


There is no ‘MG’ motif under the dynamo on the 4/44 engine, just as there are none on the later YB engines. The photos and diagram will assist identification of bits. The 4/44 engine has the luxury of an oil-pump priming plug.


Neil Cairns.