Hi Guys,
I don't often talk on this forum (maybe less than 5 times). Steve C suggested I reply to this thread. I have had 2 Butler Pro Pumps and had issues with both. After doing a take apart study on the pumps, I found that many of the "modifications" either did not exist OR were counter productive to mitigating cavitation or high flow.
After many discussions with David Butler, he agreed with my synopsis. I sent him a comprehensive write up. Butler has contacted their pump supplier and I believe Butler is in discussions with Mark Luhn to start carrying his pumps due to Mark's higher quality pumps that DO include REAL upgrades.
I have nothing but GREAT things to say about Butler's customer service. If you have an issue or questions, give them a call.
I also have GREAT things to say about Mark Luhn, He's one of the nicest guys I have met in this hobby and knows his stuff.
I am running a Luhn Pump now. My oil pressure is about 100 psi at 6500 rpm. I know that sounds high, because it is. After a couple dozen dyno pulls on my 505 IA2, we pulled four main caps and four rod caps to inspect bearings. They were near perfect and new in appearance. SO, if your oil filter can handle the pressure and you don't mind losing a few HP do to the parasitic loss, and a little more stress on your dizzy gear, high oil pressure is not a bad thing for the bearings.
Back to what others have said about 50 or so PSI at very high RPM, I believe it doesn't take much pressure to float the bearings. Don't forget, measuring pressure at the back of the engine is where the pressure source begins. As oil travels down the oil galleries and bleeds out of the bearings, the pressure at the front of the engine will be less. I have some data I collected on the dyno to show this and by how much with my setup.
Here's my engine on the dyno:
https://www.youtube.com/watch?v=ymWvrHM7Z4o
-Dave