Being an oil man I'm probably over cautious about matters lubrication. When we first started my rebuilt 3.8 engine we gave her a good crank over without ignition to build up some oil pressure & distribute oil until I could see some flow in the cambox through the oil filler. We then started the engine & had great oil pressure but I continued to observe oil flow to the cams. I deemed it rather sluggish for my liking and shut down the engine to investigate. My first suspicion was a partially blocked Y pipe from the block to the back of the head (those damn platers) but on comparing the tired engine in my donor car to the newly rebuilt unit I noticed thick copper washers had been used on the oil feed banjo bolts versus thin ones on the old untouched engine. So off came the Y pipe for investigation. No blockage at all however the thick copper washers were substantially restricting the side drillings in the banjo bolts. (original banjo bolts on my engine have their holes somewhat countersunk/chamfered. New ones not so which aggravates this condition.) So I duly ordered the correct thin copper washers with squash band & reinstalled everything. Viola! Proper oil flow to the cams.

Moral of the story. If you want to maintain a quiet valvetrain. Fit the correct copper washers to your cam oil feed banjo bolts.






Wrong thick copper washer



Correct thin copper washer with squash band



New banjo bolts with no chamfer on the drilling (I used my originals)