External Engine - 848 and 997cc

848 and 997cc Engine Identification

The 848cc A Series engine was the original engine in the Mini when the car was launched in 1959.  It continued in production until the cessation of the Mini Van, the last batches of which made it to commercial fleet operators in early 1984.  Like other Mini engines that continued in production after the 1970s, the 848cc engine received a timing chain tensioner pad  at the end of that decade. 

However it never got the strengthened cylinder block or the other 'A Plus' modifications wrought on the 998, 1098 and 1275cc engines - the 998 (which shared its block with the 1098) and 1275cc engines being scheduled to have much longer production lives in the Austin Metro. 1980s 848cc engines can therefore only be easily identified by a bulge in the timing chain cover, giving away the fact that there is a chain tensioner pad assembly inside.  848cc engines used with automatic gearboxes are different in several respects to those used with manual; 848cc automatics ceased production in 1971.

In fact, the only other BMC/Leyland vehicles to use the 848cc engine were the Mini Moke, a handful of early 1980s Metro Vans and the final batch of Austin A35 Vans built as AA patrol vans in 1968!  The latter was the only non-transverse 848cc A Series engine type ever produced, incidentally, while it would be very unlikely indeed for you to find one of the other two transplanted into your Mini.

The 997cc A Series engine is most closely related to the 848cc unit from which it was directly developed (which is why it is included with the 848cc engine in sections of this catalogue).  It only saw use in one model of Mini, the first incarnation of Mini Cooper, and was produced from 1961 to 1963.  The only other application of note for a 997cc A Series was in John Cooper's 'Formula Junior' racing cars, from which most of the components were borrowed for the Mini Cooper.

Engine serial number prefix codes are important in identifying what you have in your car and establishing which replacement parts to fit to it.  The 848 and 997cc engine number prefixes used on Mini engines are listed here for that reason.  The engine serial number is stamped on a plate affixed to the cylinder head mating face or 'deck' of the cylinder block, at the front of the engine towards the right hand side, as you look at the engine in the car.  Note that the last code letter before the serial number itself always relates to the compression ratio of the engine: H for high compression, L for low compression.

Factory reconditioned engines always lost their serial numbers in favour of an engine number plate stamped with the appropriate part number for the intended application for each engine.  In the absence of an engine serial number on a factory reconditioned unit, this is the only means of identification - but beware!

Factory reconditioned engines were more often than not built up with whatever suitable components were to hand; for example, new parts were usually plucked from the engine production line and were therefore of the latest design.  Reused components came from stocks of parts which would do the same job, but were not necessarily the same design, all lumped together.  In other words, parts used in the rebuild were frequently incorrect in a historic sense for the engine being rebuilt. 

With the advent of 85H/ serial numbers in 1969, the codes became far more complex.  85H/ was followed by a three digit number and either one or two letters. The number referred to the transmission fitted (manual/automatic, type of gearchange, type of drive shaft joints, final drive ratio etc.), the charging system fitted (dynamo or alternator), plus any unusual specifications (Police, Post Office or other utility users, export market specific requirements).  The one or two letters following the three digit number referred to emission controls fitted (type of crankcase ventilation, air intake system, evaporative loss control, etc.).  Unfortunately with regard to the 848cc engine there are too many combinations of codes to list in the space available here, but if you contact Somerford Mini with your full engine number we can 'unpick' the codes to tell you exactly what specification your engine was built to.

There never was a differentiation made between open circuit or closed circuit breathing, nor between dynamo or alternator fitment, on manual transmission reconditioned engines.  The factory instructed that the parts concerned (rocker cover, tappet cover, pulley etc.) should be swapped over from the old engine to the new one as required.  All factory reconditioned 848cc engines were high compression ratio units.

Rebuilt or Repaired 848 and 997cc Engine Assemblies

Somerford Mini Ltd. offers an engine rebuilding and repair service, courtesy of its workshop facility.  We can carry out repairs or rebuilds on late-model engines, but the extent of rebuilding on an early engine is governed by - and sometimes restricted by - parts availability. Please contact us to discuss your Mini engine requirements - it would be helpful if you could supply us not only the details of what's gone wrong with your engine, but also the full engine number (if known) and type (capacity, high or low compression, gearbox, breathing system, etc.).  The more you can provide us with, the better we can ascertain how we might possibly help you.