Chris,
The whole B Range engines are very robust but they do fail very occasionally, if you didn't know the number tells you a lot:
B = RR Gasoline engine (but often not made by RR!)
number = cylinders
0 or 1 = 3.5" or 3.75" bore.
The intention was to have a range of engines with common parts although the B41 and B61 were never made as the MoD requirements were met with the B40, B60, B80 and B81.

You can certainly re-configure any basic engine into another type and mark number, the B81 is the only slightly difficult one as the Mk.7 and onwards have different cams and CR.

The design is very old being based on a 30's Bentley engine with the design started early in WWII, some 8cyl versions were trialled during WWII.

There are a few traps for the unwary which become obvious when reading the RR Wksp Manual TSD 702.

The head gasket requires the sealing cement defined, which flies in the face of accepted practice, and along the exhaust side only to a width of 1" on both faces.

The unwary often over-tighten the heads, 35-40lbs ft is the spec, the nuts along the exhaust side are eclipsed by the casting overhang. RR say to use a box spanner with a tommy bar centrally and 6" long; the inference being as much as you can pull on such a lever!!

Main and big-end nuts have no torque setting but are tightened to a specific bolt stretch; 4 - 7 thou on bigend caps, surprisingly TSD 702 gives no figure for main bearing caps. EMER Power S 524 part 2 however gives 440 - 470 lb in for all 3/8" main cap nuts and 340 - 370 lb in for 5/16" main cap bolts. It also gives 6 - 9 thou stretch for bigend bolts.

There are no camshaft timing marks, it is timed by the classical methods using the gear teeth and the eight timing gearwheel bolts like a vernier coupling - best left alone !

All B Range engines are and must be ignition timed statically, 0deg to 2deg AFTER TDC, yes AFTER. The distributor intentionally begins the advance around idle revs and the timing allows hand cranking without danger.

Except the B40, the distributors are subtle twin point affairs that both fire alternate cylinders on alternate points and also take turns in effecting dwell angle extension for better high speed sparks. You will note the 6 cyl distributors have only 3 cam lobes and the eights only 4!! The phasing between point sets is critical or else half the engine can be mis-timed as the distributor is set to the engine against one set only assuming the other set is correctly phased.

This is easy on a six as the points are 90 deg apart making 180deg firings, you can time No1 and No6 cyls from the flywheel marks. on an eight it is essential to remove the distributor and use a bench jig.

They can of course have cracked blocks or failed liners, especially if a previous owner has not religiously used antifreeze which they should have at all times. The core plugs (or as the Americans have it, freeze-out plugs - which they never do anyway) are all screwed (unified special thread too) and cannot push out under freezing conditions.

R.