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To: SPowers2@wow.com
From: VRHS43A
Subject: RE: SOMETHING WRONG WITH MY 74 MGB IGNIT
Date: 10/27/96 12:12 PM
Scott! You have just rebuilt the engine and it fails to run
correctly. You have a 1974 MGB with standard ignition but for some unknown
reason there is a Weber carb fitted. Remember that there are FOUR systems
which need to be correct for the engine to run correctly: ENGINE; EMISSION
CONTROLS; IGNITION; CARBURETION. You have diagnosed the problem as
ignition but you may be premature.
ENGINE: Check the valve timing: Set the #1 inlet valve to 0.055",
not 0.013 (the correct setting)(you noted .15 which is wrong by a factor of
two thousandths, or by a factor of TEN). Then roll the engine around until
that #1 inlet snags the piece of paper you are sliding between the rocker
and valve stem -- in other words, the rocker has made contact with the
valve stem. The timing marks should now sit EXACTLY at TDC. Ensure you
are running Champion RN9YC plugs (no platinum plugs please!) Check your
compression to find about 140 in each cylinder -- but to ensure that they
are all the same plus or minus 10%. These tests will ensure that the
engine is ready to run.
IGNITION: Point gap of 0.015" or dwell of 60 degrees; static timed
at about 10 degrees before TDC (use your 12v test light).
CARBURETION: How old is the gasoline? After six months the
gasoline is not very good -- longer makes it worse. Of course, this
depends upon the area of the country in which you live -- and which gov't
is giving gasoline mixing instructions.
Try these first two items and contact me again -- or call me during
my technical time 1-2pm EST Mon - Thurs 616 682 0800.
Fast Forward! John Twist
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