Hi Andy:
In addition to the weak link of the early 2nd gear and the bronze
synchro, the other major weak link is the laygear configuration.
• the MGA and the early Mark 1 MGB used a laygear supported on three
(3) needle bearing sets. Two (2) sets forward and a single set at the
rear. The problem is at the rear, the single set takes a tremendous
amount of torgue and flexing. Over time, the layshaft and the needles
will wear significantly. I had a couple worn at least two (2) needle
bearing diameters deep on the layshaft. In this condition, the laygear
can wobble causing all sorts of damage, suchas fretted 2nd gear, damaged
synchro and lossing teeth on the laygear, etc.
If you are planning a 3 synchro rebuild, use the later/competition
laygear (22H1301 or 22H0931) and the 88G0400 layshaft + the correct
bearing circlip and distance tube. The later configuration uses four (4)
caged needle bearings (22H0471) that can take the output torgue. To
install this configuration you must ream the gearbox layshaft holes to a
larger diameter. There is a piloted reamer available for this rework.
The later 67 gearbox from engine # 18GBUH74720 & on has all these
features installed.
Good Luck: Rich
Boris 67B Roadster
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