Hi Cleve Crews!!
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Date: Mon, 24 Mar 97 03:54:02 UT
From: CLEVE CREWS <JAGUAR_XKE@msn.com>
To: mowogmg@dynanet.com
Subject: MGA - SWAP TO MGB ENGINE OR ENGINE AND TRANS
I'M TRYING TO FIND SOMEONE WHO REALLY KNOWS WHAT IT TAKES TO PUT AN MGB
ENGINE IN AN MGA. I'VE HAD PEOPLE TELL ME THEY HAVE DONE IT THEMSELVES,
BUT THEY CAN'T TELL ME ALL THE DETAILS. I WOULD LIKE TO KNOW ALL THE
DETAILS BEFORE I PURCHASE THE B ENGINE AND OR TRANS. I WOULD LIKE TO DO
AS LITTLE CUTTING, WELDING...ETC. I HAVE NO WELDER. MY CAR IS IN A
LOCATION WHERE IT IS ALMOST IMPOSSIBLE TO MOVE IT UNLESS IT HAS AN
ENGINE. ANY THOUGHTS OR ADVICE?
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The "A" used the 1500/1600/1622 cc blocks, all of which were three
main bearing engines. The "B" first came with 3 main bearing 1800cc
block, then went to a 5 main bearing block until production ceased.
You cannot mate a "B" five main bearing engine to an "A" transmission
unless you are prepared to do custom machining to the flywheel. You
MUST keep the plate that the "A" tranny bellhousing bolts to, because
otherwise you cannot fit the starter to the transmission. You have to
modify that plate to match the "B" 5 main block.
I don't know anything about the "B" three main bearing block, but I
suspect you will find that it will not match up with the "A" tranny
either. BMC changed the pilot shaft tip size, so you have to look
at changing the pilot bearing in the end of the crankshaft as well.
The best bet is to buy the "B" 5 main block WITH a 5 main tranny, and
thrash out the minor body work problems. You will need to enlarge the
transmission hump. The front motor mounts are the same, so no
problems there. You might have a problem matching the rear transmission
mount to the new tranny, but it will be minor. You may have to
"dimple" the firewall to clear the new starter position, because bmc
moved the starter position around a bit.
Before you pull the old engine/tranny combo, measure to the centreline
of the tranny universal yoke, and you can compare that to the new
unit after installation. If you need a different driveshaft length,
it will tell you how much to add, or subtract.
Best of luck, and please keep us posted. My son and I have started
the creation of a hybrid "A", using donor parts from a "B" hulk.
We've finished replacing the "A" drum brakes with the "B" disk brakes,
using the "A" shocks. All we needed was a set of special spacers for
the trunnion to shock arm connections, but they set the caster, so we
had to do it a couple of times to get it right.
We tried to mate the "A" engine (0 time on a rebuild) to the "B" tranny,
because the "A" tranny had grenaded, but NOTHING fit.
TTUL8r, Kirk Cowen
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