Greetings friend. The change of the slight tree bearing with the engine placed is something very difficult even for the one who has some experience but quiet, if it is done, I advise you to consult with your experts from an industrial workshop in rectification of engines to see that they advise you, now if you could disarm the parts to take out the tree and then it was the waiting and put the bearings you would be great, if you would not touch you, if you would not touch you, it would be great, if you would not touch you, if you would not touch you. If you plan to do so, try to be persistent with those of the rectifier to do it with the engine installed and so it is cheaper, but if you want to change the oil pump to see how such, nothing is lost, it is just to take out the carter and change it. Be very careful with the barilla that activates the pump that goes from the distributor to the pump and bewill that the filter and the tube where the pump subsides the oil is well uncovered, there can also be the problem ... you have it and tell me.