Does anyone know if its possible to adjust the luffing up/down speed. Luffing up is fine but luffing down is very slow. It does speed up if I rev the engine but even then its much slower than luffing up at tickover. Any ideas? Its not a temperature thing as its like this from cold or after an hour. Cheers
In the states, we refer to it as boom up and boom down, but I know what you are asking. Boom up is hydraulic power, boom down is "gravity" down. The crane puts enough hyd. pressure out to overcome the holding valve, and the weight of the boom pushes the oil to return to tank- so essentially without reinventing the wheel- you're stuck with the boom down speed. You "could" redo all the orifices and holding valves and hose sizes to speed it up- but it wouldn't be worth the money you would spend. Every old Krupp I've run seemed pretty slow. Makes it nice if you have all the jib on and are trying to boom down 2". Not so nice if you are running short main boom and in a hurry. They do seem to boom down a little faster with all the stick out and some weight on the hook. More pressure on the "gravity" down that way- and I think they seem slower with no stick out.
ah, didnt realise it was gravity down but it makes sense. I wondered if there was an adjustable bleed valve to speed up or slow down movement. The only slightly weird thing is it defiantly drops slightly faster if I hold high-ish engine revs as opposed to just tickover revs. Incidently I wonder if the main dire drum works in the same way as its much faster up than down but as its rigged as a two part wire its ok. Hate to think how slow it would be if I rigged with a 4 or 6 part hook.
The one's I ran had a two speed button on the floor that would increase winch speed and boom up- but it won't change the boom down.
Does that model Krupp have the pvr and rvr boards in the upper dash??