After experiencing the meta-physical mystery of Lucas electrics, the indignity of being passed by Hyundais, the joy of trying to identify and wipe up puddles of various liquids from the garage floor, and the embarrassment of never knowing whether a destination was attainable or not, I decided to compromise the originality my LBC with a Japanese drivetrain. If you wince at any parts that don't come in a box emblazoned with the Union Jack, read no further.
The following describes replacing the BMC A-Series engine and gearbox with a later model Toyota four-cylinder engine and either a four- or five-speed gearbox. These procedures may, in fact work on a 1500 model, but I have not personally verified this.
The applicable Toyota engines, from about 1974 through 1981:
|2T-B||1588cc||Hemi-head, pushrod OHV||70bhp||early engine|
|2T-C||1588cc||Hemi-head, pushrod OHV||75bhp||later, with better head, <79 Corolla|
|2T-G||1588cc||DOHC, Dual Mikunis||125bhp||twin cam version, 74-78 Levin/Sprinter/Corolla|
|2T-GE||1588cc||DOHC, Fuel Injection||115bhp||fuel injected, 79-80 Levin/Sprinter/Corolla|
|2T-GEU||1588cc||DOHC, Emission||105bhp||non-Yamaha head with FI, 81-82 Levin/Sprinter/Corolla|
|3T-C||1770cc||Hemi-head, pushrod OHV||75bhp||stroked version of 2TC, 80-82 Corolla|
|3T-GT||1770cc||DOHC, FI-Turbo||180bhp||twin cam, twin plug, turbo, 81-82 Levin/Sprinter/Corolla|
|4T-G(T)||1770cc||DOHC, various||+200bhp||factory racing, rally, very rare, also turbo-versions|
|4A-GE||1587cc||DOHC, Fuel Injection||112-130bhp||85-86SR5 and FX16 Corolla|
All the engines with a 'T' as the second letter have the virtually the same lower block. The 'A' engine also share a common block. These will be referred to later as either a T-block or A-block engines.
The 'TB and 'TC engines are quite easy to find in wrecking yards everywhere. None of the 'TG engines were ever imported to the USA, although they are available overseas or from specialty importers. Many aftermarket suppliers offer high performance products for the T-blocks. With stroked crankshafts and overbore pistons these engines can be brought up to 2L displacements and close to 200hp.
The 4AG is the base engine for the Toyota Atlantic series race engines. Toyota Racing Developments and HKS have a wide range of performance parts for these engines. Because of the decreased bore centers, the maximum displacement possible is around 1700cc. The A-blocks are about 2 inches shorter than the T's.
The recommended transmissions for this swap are either a T40 or T50 aluminum case manual. The gear ratios are very similar, with the T50 having a .82 overdrive fifth gear. Later model T50 have a extended gear selector housing that must be replaced with a earlier short housing in order to obtain proper lever location.
Much of the following is based on the assumption that you have a Haynes Automotive Repair Manual #265, knowledge of Spridgets, a fairly extensive workshop and tool collection, and basic fabrication skills. The work to be carried out is not particularly difficult, but should not be attempted by anyone not fully confident in their mechanical abilities.