I think there were some minor casting differences in addition to the
smaller pilot hole in the crankshaft on the Marina engine. When I bought my
71BGT in 1983, I spotted some difference in the engine - enough that I knew
it was not the right engine in the car. It was an 18V engine though, and
I'm still not sure what it was in its appearance that tipped me off. The
head also differed in that it had the small cooling line that was used for
the automatic choke for a ZS carb that was blocked off. A British Leyland
mechanic I knew was able to identify it as a Marina engine by sight.
When I replaced the transmission with an o/d unit, I had to reuse the pilot
shaft part of the old transmission which had been altered so it could fit
into the smaller pilot bushing of the crankshaft (looks like it was turned
at a machine shop). I still have this piece in the garage as I later
replaced the engine with a 72 18V engine a few years later.
The head, which I assumed came with the Marina engine and thus a Marina
head, was used on the replacement engine for another 15 years and has now
been retired during a recent overhaul. I still haven't started the new
rebuild yet but its only weeks away I think.
David Councill
67 BGT
72 B (71BGT reincarnated)
At 10:25 AM 10/21/2002 -0700, Dodd, Kelvin wrote:
>In the US the most likely replacement, non-MGB 5 main block or engine is
>going to be the Marina. (There are a few gold seal factory rebuilt engines
>around, and there are also a few rebuilt units of dubious heritage that came
>from other vendors in the UK.)
>
>The Marina engine was readily available, as the cars were not very well
>received. Many ended up in scrap yards due to lack of spares, or repairs.
>In many cases the only part salvaged was the engine which usually could be
>refurbished with rings and rod bearings. The federal spec Marina engine was
>identical to the 73-74 18V MGB engine except that the crankshaft had a
>smaller id pilot hole. In some cases the crank had the large MGB id pilot
>with a steel bushing fitted. It is my understanding that all 18V cranks
>were pressure cast in the new production facility, but I am open to
>contradiction. (I'm not certain about cam specs, and don't have parts books
>readily to hand. The distributor was different, as the advance curves were
>specific to the carburation and vehicle weight).
>
>I'm not aware of any casting differences between the US supplied 18V blocks.
>Perhaps "Telewest" is thinking about the Marina oil pan, which had an
>extension welded on the bottom which bolted to two bosses on the
>transmission bell housing.
>
>The UK spec 1800cc Marina engines were available in a variety of
>specifications including Low Comp, High Comp and Twin Carb and were a very
>different beast. The 1275cc A series engine was the more popular option in
>the UK, so you can imagine the 1800 B series was classed as a hot rod.
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