cooling fan motors
Hesketh-Jones (Harvest Gold 1904) from Cornwall sent in a note concerning
cooling fan motors recently and Peter Beadle (Damask 0503) from
Gloucestershire well known for his comprehensive knowledge of V8
parts, has contributed a few comments. (Dec
mentioned that recently he had been re-reading the September 1982
edition of Safety Fast! and in the V8 Column saw a mention that
the "V8 radiator cooling fan motor is now supplied under
Lucas part number 78586 and has ball bearings instead of sleeve
bearings." Gordon recalled that when he first bought his
MGBGTV8 in 1986, those motors failed quite regularly (at least one
a year), so it was a real problem when the source of supply dried
up because of the Yugoslavia /Bosnia problems in the early 1990s.
Unipart re-sourced the motors and they are now available with sleeve
bearings again. His routine since then has been to take the motors
off once a year and to soak oil carefully down into the bearing
- this has extended the life of the motor, even with his heavy usage,
to seven or eight years which he feels is quite acceptable. Recently
one of the motors failed and he found the latest version (supplied
under part number BHA5256B) as a replacement definitely has
sleeve bearings. However when he came to fit the motor, he found
that it had no part number or country of origin markings stamped
on the body of the motor. When he came to examine the replacement
motor, he also found the outside diameter of the replacement motor
was 2.8 inches instead of 3.0 inches on the existing unit so the
new motor wobbled about in the mounting brackets. Although this
was annoying, Gordon's solution was to Evostick strips of rubber
to Contents listing
took up the slack and presumably gave some insulation from vibration.
The rubber came from an old inner tube so he felt it would be reasonably
tolerant of hot, wet and oily conditions the fan motors experience.
mentioned the current part number for the V8 cooling fans is now BHA5256Z
which has an outside diameter of 3 inches. He also mentions two important
for the motor. As the twin V8 cooling fans are mounted just inside
the front grille, they inevitably getting a battering from water and
road muck, and during the Winter months salt spray too. Some members
have used the bottom section of a plastic bottle as a protective shroud
for the motor thereby extending the life of the unit.
of rubber. Care over the choice of the rubber making up the slack
between the undersize motor and the brackets is needed to ensure the
rubber does not flex too much in their mountings when the fans come
on. Also the choice of rubber material needs to be one which does
not decompose in the hot and wet conditions in front of the radiator.
The concern is that because the fan blades have to be adjusted so
as to be as close to the forward facing radiator matrix as possible
to maximise the cooling effect, the consequences of substantial flexing
of the motors when activated or movement because the rubber mounting
has decomposed, could be damage to an area of the radiator matrix.
Peter feels a suitable alternative mounting material might be cork
because he recalls that the Special Tuning fan kits (part number STN117)
were supplied with brackets with a cork insert.