BL R-series engine
{{Short description|Line of petrol engines for the Austin Maestro car}}
{{Use dmy dates|date=December 2016}}
{{Use British English|date=December 2016}}
The R series is a line of petrol engines introduced by British Leyland in 1983 for the then-new Austin Maestro. It was only produced in one capacity—1.6 litres.
Design
The engine was essentially a lightly modified version of the E-series unit found in the Maxi and Allegro. The main differences over the older engine are to the sump and gearbox mounting flange, which were adapted to accept a traditional "end-on" transmission unit which had been bought from Volkswagen in place of the traditional BMC transmission-in-sump arrangement. It retains the 1.5-liter E-series' bore of {{convert|76.2|mm|in|2|abbr=on}} along with a longer {{convert|87.6|mm|in|2|abbr=on}} stroke. The longer stroke was obtained by a revised crank throw.
Like the E-series, it has a cast iron block and aluminium head.{{cite journal | journal=Le Moniteur de l'Automobile | page= 8 | title=BL passe la 3ème vitesse | trans-title = BL puts it into third | last=Renaux | first=Jean-Jacques | location=Brussels, Belgium | language=French | volume=34 | number=764 | date=1983-03-10 | ref = mon764 | publisher=Editions Auto-Magazine }} As with the E, the cylinders are siamesed, to fit the biggest bore cylinders possible. The combustion chambers were of Weslake's kidney-shaped design. The carburettor for the regular version was a single-venturi one with an automatic electronic choke, while the MG version received two twin Weber 40 DCNF carburetors and none of the fuel-saving electronics. Maximum power is {{convert|81|and|102|hp|kW|0|abbr=on}} at 5,500 and 6,000 rpm respectively.Renaux, p. 11
Problems
The R series was mainly a stop gap, and had a very short production run that lasted barely two years. BL had been working on a more substantially revised version of the E series, but this was not ready for production in time for the Maestro's already badly delayed launch. The company was instead forced into launching the Maestro with the half-developed power unit which cost the company dearly—R-series-equipped Maestros soon gained a reputation for hot starting problems, cylinder head gasket failures (endemic to the E series also), and premature crankshaft failure. Because the E series was turned through 180 degrees in order to accommodate an end-on transmission, the R series was fitted to the Maestro with the carburettor facing the front of the car, which also led to a reputation for carburettor icing in cold weather.
The endemic problem of crankshaft failure was later attributed to flexing of the crankcase – because the E series relied upon the heavy sump/transmission unit to give additional strength to the cylinder block casting, this caused problems when a plain sump{{dn|date=June 2025}} was bolted in its place. The sump in question was an aluminium alloy casting.
The R series was superseded in 1984 by the S series.