Jethogger@aol.com wrote:
>
> Hello Neil. I have a 73 Austin Marina in my back yard. You say the crank is
> casted.
WARNING, rather long-wynded again........
First...here are the installation differences between the two similar
engines;-
Single Carb Marina 1800 UK MGB
single row timing chain double row timing chain
engine mountings in centre of block engine mountings on front plate
sump has gearbox steady bars normal 'B' series 'aft' sump
Crankshaft flow-cast crankshaft forged
rear engine plate HUGE rear engine plate BMC type
flywheel HUGE Leyland type flywheel .. ..
gearbox 3 rail Triumph type gearbox 3 or 4 syncrho BMC
big platic cooling fan three blade metal or electric
cam timing 5;45;40;10 cam timing 16;56;51;21
single SU HS6 twin SU HS4
Marina 1800TC/ MGB differences;-
As above but using MGB cam and twin SU HS4, using cheaper flow-cast
crank.
The Marina used the 18V engine with the 12H4635 cylinderhead, with the
offset rocker oil feed, ( as did the Sherps Van petrol version.) The
rocker pedestal has a little 'foot' on it to line up with the different
oil drilling, moved to get more water around the exhaust valve seats.
This head was not used on the MGB until 1975. 18V engines have 12H3503
blocks. The central engine mounting of the Marina are on all of them,
bolt holes can break through into the crankcase--cured by fitting a
bolt!!
Whilst the rear plates are different, they are held on by the same bolt
holes and are interchangeable, as is the front plate.
BL biult an engine manufacturing plant specifically for the Marina,
making the 18V 'B' series, virtually identical to the MGB engine; and
the 1275cc 'A' series, similar to the Migdet engine but with an oil
filter ABOVE the starter motor. The Marina engine was much cheaper than
the MGB, the flow-cast crankshaft was a copy of the FORD of America
system. The head was improved, as above, and eventually both MGB and
Marina shared the 18V engine. The Marina was a family saloon, ( sedan)
and sold millions. It used Morris Minor torsion-bar front suspension and
king pins. The clutch housing is HUGE, as is the cast iron gearbox, used
on the Truimph Toledo, Sprint, 1500, TR7 and later Midget 1500. (This
gearbox on the later Midgets means you can fit an overdrive gearbox from
one of these saloon Triumphs, if you can find one.)
> Well tell me about the polit bushing size. It has a tr7 tranny bolted to it.
> (4speed)
> Is the hole smaller than a 5 main B tranny. What does your manual say. Does
> it use a oversize ploit bushing? John Flintstone, ga
I have built a few kit cars using old Marinas, and modified a few Mk4
Magnettes with MGB engines, I seem to remember the gearbox first motion
shaft, ( clutch shaft, pilot bush, ect,) on the MGB was about 1"
diameter, and the Marinas only 7/8" diameter. The early 3 synchro MGB
had a 7/8" shaft as well....( these sizes are from MEMORY, and may be
wrong.)
Just turn up a suitable bush, the hole in the crankshaft is the same
size.
Neil.
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