>>I have a friend who would like to put an MGB engine
>>and gearbox into his MGA. I understand that the
>>front motormounts are no problem, but the rear
>>mount must be changed/modified.
Don't have any info on the tranny swap ("I don't
need no stinkin' synchro on first gear"), but if he
is looking to swap engines and retain the stock
tranny ... installing a 'B' 3 main engine is easy
a 'B' 5 main engine is a bit more difficult.
To fit the 'B' 3 main engine you swap the 'B' rear plate
for one from an 'A' (so the engine bolts up to the
'A' tranny) and the 'B' flywheel for the one from the 'A'
(so that you can use the 'A' clutch). The tranny input
shafts have the same diameter so the spigot bush
(pilot bearing) isn't an issue. The 'B' 3 main has the
mechanical tach drive so the mechanical tach isn't
an issue. The 'A' exhaust manifold can be used but,
IMO, it is a bit restrictive ... and 'A' tubular header
should be used ... the 'B' exhaust manifold can be
used but will require shiming the engine mount.
(Note: the lighter 'B' 3 main flywheel and superior
'B' clutch can be utilized - see below)
To fit the 'B' 5 main engine is a bit more difficult ...
the adapter plate houses the rear engine seal
and the bolt/pin pattern on the crank prohibits the
use of the 'A' flywheel. The 'A' adapter plate is easily
machined to accept the rear engine seal. The use
of early 5 main flywheel (uses the same ring gear
as the 'A' and 'B' 3 main flywheels) means that the
'B' clutch must be fitted ... the 'B' clutch is thinner
than the 'A' clutch so you swap the front cover (the
plate that the release bearing lever bolts to) on the
'A' tranny for the front cover/release bearing lever
from a 'B' 3 snychro tranny. A special spigot bush,
available from Moss, must be used to compensate
for the small diameter input shaft on the 'A' tranny.
The 5 main block doesn't have a mechanical tach
drive so an elec tach is used ... have heard that
some of the 5 main blocks have the boss for the
mech tach drive and all thats required is machining
to accept the mech tach drive. Exhaust is handled
as outlined above.
>>Has anyone done this job, and if so, what problems
>>will he run into and what are the solutions?
I have not done this yet ... the above is based upon
conversation with several different folks kind enough
to lend and ear, answer my questions, and test various
combinations of bits ... so be *warned* that YMMV!
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