There have been occasional oil pump gear & cam gear failures when using a HV oil pump. To prevent this I added an external oil feed directly to the cam gear. I can't take credit for the idea of this modification as it was originally done by another member here. Pressurized oil is taken off the oil pressure sensor fitting (on the XJ) location and fed to restricted orifice fitting in a 1/8" drilled and tapped hole behind the distributor gear. I originally used a copper line with one end formed to a restricted orifice and passed through the block.
I later was concerned that the copper line would eventually fatigue and crack creating an oil leak. I revised it using a high pressure push lock hose with AN fittings on each end and a .010” flow control orifice (McMaster Carr 2822T11).
This is the final version:
This is the 1/8" NPT hole tapped behind the distributor. In the hole is the .010" restricted orifice fitting. Behind that is an NPT to AN adapter, then the AN fitting, and finally the hose.
This flows plenty of oil to the distributor gear.
The sensor you see above where the line picks up is a temp sender for an Arduino based multi-gauge I created. I also moved the stock pressure sensor to the rear of the block as well as added an additional sensor for the multi gauge. I feel that this location gives a better idea of final oil pressure as it is at the end of the oil galley. Some Jeeps use this location for their stock sensor. On the XJ blocks the boss is there but it is not drilled and tapped. I drilled and tapped the hole for a 1/8" NPT fitting.
I then used fittings to install the two sensors at that location.
Also, I was once again afraid of fatigue issues on the brass fittings so I later changed to steel fittings. I think I will later change that to a remove mount with a hose to alleviate any chance of cracking from fatigue as the sensors + fittings do add some weight.
One other thing is that if you are using a HV oil pump do not use a heavy weight oil like 20w-50. 10w-40 or lower.
