Hello all,
Happy New Year!
I wonder if anyone can provide some assistance; I am nearing the end of an engine rebuild and will soon be ready to refit the oil pump. I have a couple of questions:
- Does it require packing with petroleum jelly in order for it to lift or this not necessary due to its position?
- Once fitted, does anyone have any tips for a starting point for which to begin the adjustment of the oil pressure?
Thanks in advance for any help.
All the best
Matthew
75 engine oil pump
-
patrick hiron
- Posts: 19
- Joined: Mon Nov 03, 2008 4:30 am
Re: 75 engine oil pump
Hi
I wrote an article on the P3 lube system for Freewheel some time ago . It's a good idea to pack the oil pmp with vaseline . Gear pumps have a nasty habit of not priming , which can lead to a nasty event when you try to start the engine .
Don't forget to replace the ball bearing in the pressure control valve and to re seat it by tapping the ball with a hammer, using a brass drift between the hammer and the ball !!
I found the best bet was to remove the plugs , slacken the oil return line from the filter to the sump , and the feed to the oil presure gauge.Turn the engine over on the starting handle until you see oil leaking from these two points , this ensures the oil pump is primed and delivering oil through the engine . Tighten up these two connections and turn the engine over on the starter and check the oil pressure . You may have to bleed the oil pressure gauge pipe at the back of the gauge to get a reading .
Remember you dont " set the oil pressure " by fiddling with the fine threaded adjuster on the side of the sump . That big nut simply sets the pressure at which the oil pressure relief valve[PRV] lifts . At this point some of the oil is directed back into the sump instead of being circulated to the bearings,The PRV is set to avoid damaging the engine with very high pressure when starting from cold . Under normal operating conditions the PRV should be closed , all the oil should circulate around the engine . The actual oil pressure is then set by the: engine revs , condition of the bearings and the viscosity of the oil .The PRV setting is controlled by a spring and is not affected by temperature
I set the PRV initialy by screwing the adjuster half way in and observing the cold oil pressure . This gave a reading of around 55 psi cold . High enough to circulate the oil without damaging the engine 's internals . The oil pressure fell to 40 psi hot , indicating that the PRV had closed and my rebuilt engine's bearings were in good shape
Don't forget to tighten the lock nut on the PRV set pressure adjustment when you have finished
Cheers
Patrick
I wrote an article on the P3 lube system for Freewheel some time ago . It's a good idea to pack the oil pmp with vaseline . Gear pumps have a nasty habit of not priming , which can lead to a nasty event when you try to start the engine .
Don't forget to replace the ball bearing in the pressure control valve and to re seat it by tapping the ball with a hammer, using a brass drift between the hammer and the ball !!
I found the best bet was to remove the plugs , slacken the oil return line from the filter to the sump , and the feed to the oil presure gauge.Turn the engine over on the starting handle until you see oil leaking from these two points , this ensures the oil pump is primed and delivering oil through the engine . Tighten up these two connections and turn the engine over on the starter and check the oil pressure . You may have to bleed the oil pressure gauge pipe at the back of the gauge to get a reading .
Remember you dont " set the oil pressure " by fiddling with the fine threaded adjuster on the side of the sump . That big nut simply sets the pressure at which the oil pressure relief valve[PRV] lifts . At this point some of the oil is directed back into the sump instead of being circulated to the bearings,The PRV is set to avoid damaging the engine with very high pressure when starting from cold . Under normal operating conditions the PRV should be closed , all the oil should circulate around the engine . The actual oil pressure is then set by the: engine revs , condition of the bearings and the viscosity of the oil .The PRV setting is controlled by a spring and is not affected by temperature
I set the PRV initialy by screwing the adjuster half way in and observing the cold oil pressure . This gave a reading of around 55 psi cold . High enough to circulate the oil without damaging the engine 's internals . The oil pressure fell to 40 psi hot , indicating that the PRV had closed and my rebuilt engine's bearings were in good shape
Don't forget to tighten the lock nut on the PRV set pressure adjustment when you have finished
Cheers
Patrick