18-12-2018, 03:37 PM
We fitted a second set of oil jets to the new supercharged engine we built, I sized them to match standard jets. We did the pump-paraffin-through-the-system trick by utilising an auxiliary pump which is driven via my big battery drill, one end of the pipe into a bucket of paraffin, the other end stuck onto the oil pump pick-up (it pumped past the vanes). Spin the drill and adjust each jet to have the maximum accuracy as well as duration into the crank pocket - the latter by bending the jets towards the crank axis as per the Mike Forrest double oil jet conversion published in the 750 Bulletins way back when.
If you are using a Phoenix crank it's important to note the the pockets on either side are not exactly in line, so you need to test both sides of the crank. In our case I had opened up the quite small Phoenix crank pockets quite a bit as well as radiussed the oil feed hole into the crank as much as I could to facilitate better flow. I then adjusted the jets to provide even streams of fluid into each pocket.
Paraffin goes everywhere, so we did it outside over a large sheet of plastic with a large catch drum under the motor.
Some pictures of the double oiler mod - with 4 oil jets now fed by a 20% bored out pump we are still getting 2.5lbs at pace. You don't need much pressure to provide a steady stream of oil through those little jets and upping jet pressure to a hefty PSI won't actually get any more oil into the crank, there is a finite amount that can be crammed into that little pocket, the rest will just splash feed everything including the center cam bearing. I'd stick my neck out and say that the splash at a 20% overbore with only 2 jets would be more than the motor needed for oil cooling, never mind lubrication.
More info here --> http://www.austinsevenfriends.co.uk/foru...gle+seater
Aye
Greig
If you are using a Phoenix crank it's important to note the the pockets on either side are not exactly in line, so you need to test both sides of the crank. In our case I had opened up the quite small Phoenix crank pockets quite a bit as well as radiussed the oil feed hole into the crank as much as I could to facilitate better flow. I then adjusted the jets to provide even streams of fluid into each pocket.
Paraffin goes everywhere, so we did it outside over a large sheet of plastic with a large catch drum under the motor.
Some pictures of the double oiler mod - with 4 oil jets now fed by a 20% bored out pump we are still getting 2.5lbs at pace. You don't need much pressure to provide a steady stream of oil through those little jets and upping jet pressure to a hefty PSI won't actually get any more oil into the crank, there is a finite amount that can be crammed into that little pocket, the rest will just splash feed everything including the center cam bearing. I'd stick my neck out and say that the splash at a 20% overbore with only 2 jets would be more than the motor needed for oil cooling, never mind lubrication.
More info here --> http://www.austinsevenfriends.co.uk/foru...gle+seater
Aye
Greig