AC HD11

[Old Doug]

The other day we were riging up a fan on a engine and it got me to thinking. 30 years ago i worked part time as a mechanic for a guy that had 3 HD11s. He was a great guy to work for and every day was like being in school. He had been around Dozers about 50 years. I remember doing something to the fans on them in the spring and fall to change air flow for the operaters benefit. I thought i unbolted the fan and turned it around and bolted it backup but that would not change air flow. They were late 60s models.

[kopite]

Used to turn the fans on Cat machines in the winter. Normally the fan would blow air through the rad away from the machine. When turned the fan would suck the warm air through the rad and blow it along the machine towards the operator. Even when the temp was below freezing it was like a summers day for the operator once the fan was turned.

[Old Doug]

What got me thinking I was helping to put a fan on a engine and it blowed the wrong way so we turned it over and it didnt change. Maybe some fans can be turned and some cant be. On some cats the blades can be turned by hand without unbolting them.

[FOWLER MAN]

Hi,
Some tractors were supplied with optional blower or sucker fans, but they COULDN'T be reversed by turning them.
I had two spare fans for the Challengers for seasonal changes.
If you had a cab on the heat from a sucker fan was unbearable in hot weather, but you needed no heater in the winter.

I helped look after ten Allises in the 60s, five of them HD16s and I later owned an HD21 myself. I dont know what you could have done to reverse the air flow short of changing the fans.
Fred

[nick lamb]

I briefly had a reversed fan on a D8.The cab soon got hot and the windows caught any soot aand dust the fan chucked at them.No good so I swapped it when time allowed.
There is a debate wether a sucker fan is a blower or a blower fan is a sucker???.I reackon women of the short skirt,high heeled variety may have the answer. .I don't.

[tctractors]

The turning around of Fan assemblys is realy a non starter, a blower fan (standard fit) on a D8 is forced onto the carrier hub by the wind it pumps, sucker fans pull towards the radiator its a bit dodgy on D8's?? anyhow just turning the fan 180 makes a blower fan a nothing fan as it does not have the correct shape on the blades to move the air correctly, D8's did have a reversable fan that cost a fortune that was more trouble than any benefit,there was 2 styles both involving rotation of the blades, D8's 68A upwards ran very hot always so engine blown heat over the pilot with all the dust etc would not be much good, D8's are best run with the high output Tropical blade fan, a blower fan (fixed Blade) cannot ever become a sucker fan through 180 rotation, the blade setting (angle) is totaly incorrect, it's a bit of a tale realy, a water cooled engine needs 3 times the air volume blown through the rad than an air cooled engine needs blown through the cylinder fins, I have had plenty of pilots tell me to turn the "fan Mate" also I have found the fan fitted incorrectly on a few engines, all it causes is over-heat.

[LDK]

I am pretty sure that every D8K I have been on had a sprung loaded reversible fan and I always appreciated it and a couple of tarps come winter if I happened to be driving a convertible:-)

[kopite]

tctractors, I have to disagree with your comment that a D8 68a with a fan blowing heat on the operator would not be much good. It was a godsend in the old days on a machine with no cab, it worked great. In the UK it was standard practice for many companies to turn the fans and when I came to Canada operating machine with no cab in -20 temperatures was unbearable without the fan turned. The hard part of the job, once the fan was turned became the wet muck freezing on the side of the box and then the apron wouldn't go down or the ejector wouldn't push the muck out. Had to jackhammer the frozen muck off several times per day. The only time dust blowing on me (a minor problem) was if I went over a bump and the maching dropped down with a bang and all the dust inside the bellypan would blow out for a few seconds. Most machines now have cabs and big heaters so I imagine turning the fans is something that might seem a bit of a tale.

[deltasierra]

Been there, done that, to reverse airflow either reverse rotation or reverse fan blade pitch.
Turning the fan round on a typical curved blade would reduce airflow considerably and the engine would run hotter, not a problem in -20C. On an open tractor any reduction in airflow would be very welcome for the driver
We have used "pusher" fans on pumps and generators with silent enclosures to avoid all that heat inside the box.

Dave

[tctractors]

Kopite, I have to disagree also, D8H/K tractor blower fans do not turn into sucker fans unless they are the Reversable blade items, there was 2 styles 1 using a spring lock action, the other with locking plates that you removed then turned the blade and re locked, the spring ones the blade was pushed down and rotated with some trouble involved, their was a long spanner key to help things also, but I have to stick to my line, a blower aint' a sucker, I work on D8H/Ks near every month for the last near 40 years so I have played about with em' some, I hope I dont sound like my bigest "Fan"

blowing lots of wind tctractors