Praga truck trial

[marcus]

Had some fun recently in deep water, checked the snorkel etc, wading in water 6 feet deep seemed to loose lots of power, looked like when the fan hits the water. Being an air cooled virgin is this going to cause any damage, would slackening the belts help or do I just not worry about it and press harder on the loud pedal ;)

[haymish]

careful with fan-gets traction in the water and tries to move off mounts-can lunch anything in way if it breaks free.standard trick is to loosen fan belt or remove it if playing lots but best answer is fit a viscous fan-like on classic range rover-cos it just stops when water resistance gets too much.

[marcus]

Fans on air cooled engines engines are more like turbine rotors internal of the front engine casing, quite different to a viscous unit

[haymish]

owned a few air cooled beasties over the years and water always a hassle with fans-just be aware of the enormous strain water puts on a fixed fan if belt not slipping.whole fan tries to leap forwards as it gets bite off the water-seen many an off roader with the fan stuck in the radiator when it lets go .owners fitted every deep water goodie known to man and think they got it sorted but forget that water, having so much mass compared to air,really gives a fan a hard time.could always put a big fat snorkel on for the fan

[KarlJ]

You could put a tensioner wheel on the belt that you can engage or disengage from the cab...

[haymish]

or transplant a good electric one into housing with on/off switch in cab.

[marcus]

Have considered hydraulic drive for fan or air tensioner for belts, was just curious as to how these air cooled engine fans reacted with water, the mounts/ bearings on it would probably rip the block out the chassis before letting go Also am gonna pressurise the bellhousing, maybe just 5psi, found the clutch slipped when full of watery sludge, bottom bung doesn't seem to keep all the water out

[marcus]

Our recent jaunt to Avon Dassett


[youtube]http://www.youtube.com/watch?v=N5pSOhhh ... ZJ0Y41l_0w[/youtube]




[youtube]http://www.youtube.com/watch?v=q7wlMNCx ... ZJ0Y41l_0w[/youtube]

[youtube]http://www.youtube.com/watch?v=AIWQdJ0r ... ZJ0Y41l_0w[/youtube]

[youtube]http://www.youtube.com/watch?v=aRlUHWaf ... ZJ0Y41l_0w[/youtube]

[youtube]http://www.youtube.com/watch?v=Kqbl7Ng5 ... ZJ0Y41l_0w[/youtube]



[youtube]http://www.youtube.com/watch?v=XXgqig64 ... ZJ0Y41l_0w[/youtube]

[jamie_grieve]

Nice to see someone out playing in the mud.

[Rob Reznik]

Nice - still looks a bit too much air in those tyres though.

[marcus]

Was good fun, but you're right Rob, way to much air in the tyres. Was too lazy to let them down, and didn't want to embarrass the others!

[duncan]

On the whole fan-and-water thing, ABRS mentioned before that the engine is a Tatra one (dry-sump, which is awesome). I'm not sure about the specific engine in the Praga, but the ones in the Tatra are not belt driven, they have a fluid slipper clutch, and the fans are made of metal. Result: no belt to adjust, nothing breaks