572 BBC Blower Engine - Low Oil Pressure Problems
 

Hello all,

What I have: 572 BBC with 871 blower. Fully built engine, roller cam, valve-train, JE pistons, etc. I was not the original owner, and the work was done by previous owner which I am attempting to get in contact regarding the shop who built/tuned it as well as specs. The boat has two engines, so I have an identical one sitting next to it with no such issues, has all the same parts/oil/new gauges etc. and maintains a great 40-45 PSI of oil pressure all the time.

Port engine starts out great with ~40 PSI of oil pressure. After it gets remotely warm, it drops to about 25-30, if I run it a little bit in the 3000-4000 RPM range, it drops to 20-25 PSI where it stays with minimal response to throttle change, drops even lower when idling to 5-10 I'd say. I know that I shouldn't have but I couldn't help myself; the engine runs like a monster. Makes killer power, sounds awesome, no rattling, knocking, clacking, etc.

If I let the engine sit shutdown for 10-30 minutes, it starts out at 40 again but drops off.

Things I've done:
Oil changed from 15W-40 to AMSOIL 20W-50 Z-Rod with new WIX 51222R Filter. I have not cut into the old filter to check for anything.
New Mechanical Oil Pressure Gauges (All have told the same story)
Checked everything over, can't find anything amiss.

At this point, I'm fearing I'm in for a big money rebuild. Possibilities I'm aware of:
Bearings
Bottom end Clearances
Stuck oil pump, bad spring, improperly torqued, missing screen etc.
Distributor
etc.

Let me know what you think. Currently running 950 HP or so.

I'm working to track down as much information as I can on the engines but please let me know what you guys think. Also, any guesstimates on what I'm looking at spending here for a take down, given it needs bearings/crank polish?

Thank you.

How is the oil temp?

Pretty much perfect. Obviously I haven't been pushing the boat too much for fear of making a window in the block but it gets up to a normal 220 or so and stays there +/- 10, cools down quickly.

40-45 is the most you see?? that is not enough, I would be cutting filters open to check things, general rule is 10PSI per 1000 rpm, I run big clearances and high pressure and volume pumps, I barely drop below 50 at idle on both and see 75-80 under way, if you are below 50 under 2000 rpm things need addressed, I would use a mechanical gauge as you may not even have an issue as electric are not always accurate.

Interesting. Thank you. Both engines have 2 sets of mechanical gauges that all agree. I don't have electric gauges.
Brand new filters installed. Both looked good but I will cut them open and see what's what.

Are you running team filters ?

WIX 51222R's.