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271
V8 cooling fan
motors
Gordon
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
02)
Gordon
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.
Lucas
or 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 inside the |
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brackets, which 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.
Peter
Beadle 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 points.
Protection 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.
Choice
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. |
