Re: One oil pump modification now on file

Posted by Ross On 2014/7/1 6:35:52

Per request, here is an easy modification I made to the oil pump in my Packup to prevent wear to its newly rebushed housing, and even it it does wear, to prevent any air from being drawn down the shaft. As discussed long ago here, this influx of air is what causes lifter collapse and bearing failure.

I crossdrilled the housing so that a small amount of oil from the output side is fed into the input shaft bushing.

First photo shows the general trajectory of drilling. The vertical location is approx. in line with the centerline of the relief valve and the object is to hit the output passage just past the relief valve seat area.

First step was to drill a hole from the outside only as far as the input shaft bore and make just a drill point mark on the far side of the bore. I used a 9/32 for this.

Second step was to drill a very small hole, about 5/64 through into the oil output passage. Done

If you like you can plug the entrance hole with a wee screw, but if your shaft fits nicely that will hardly be necessary. Last photo shows the drill bit through.

Attach file:

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