Young Performance

Did you make any changes in or possibly leave out the windage tray? It sounds like the crank counterweight may be digging a hole in the oil. I've seen it a few times.
One other thought.....did you change the harmonic balancer or are you running a Fluid Dampner? Myself, along with several other builders had issues with Fluid Dampners causing a loss of oil pressure at higher rpms. I don't use them anymore. This was quite a few years ago, so I don't know if the newer ones still do it. I never did figure out why they caused a loss of pressure, but it was definitely the balancer.
As mentioned, check it with a mechanical to be sure you actually have a problem.

Eddie

doctor_ratz

Eddie,
No mods to the tray, and I am positive it is there. The dip stick is completely below the tray, so I know the oil level at rest is below the tray when it is full.
I am using ATI Super Dampners, not Fluid Dampner

kvogt

drop your oil level 1 qt and see if it helps.

liquidlounge

iTrader: (1)

Your check valve(s) in the filter pad are correct?...it sure sounds like oil heating up to me. Where is your oil temp sending unit?

TEXASRPM

Performance Engines need Performance Oils

straight weight 30 is not adequate in my opinion.

WOT extended periods + 30 W = $$$

This is the best
http://www.amsoil.com/storefront/rd50.aspx

articfriends

iTrader: (1)

I COMPLETELY agree, I ran 30 weight on the dyno but it was too thin at extended intervals on the water, I have a blown 540, 14 qt off shore pan. 20/50 synthetic and appropriate size oil cooler , adapters fittings and lines and my oil pressure is 60-70 psi fully warmed up at 4500-6200 rpm's.
Things to do in your case: what are your rod and main clearances, if they are .0025-.0035 you will NOT be able to run 30 weight, if they are signifigantly closer to stock it may be possible.
oil temp-I do not have oil temp gauge on my boat and I doubt you do or you would be telling us your temp but you can buy a cheap infrared temp gun and shoot temps on your filter immediately after running hard and it will tell you ALOT.
Oil bypass differential valves (if you have them), std ones open way to easy, you need ones that are 30 psi otherwise your oil may not even be going thru the coolers.
fittings-if you run stock merc oil lines and adapters you need to run stock main and rod clearances otherwise they become too small, I have seen guys running "performance " clearances on the crank along with a high volume pump but stock bypass valves and tiny merc adapters, fittings and lines, if it takes 8 gpm to hold oil pressure on your motor at 5000 rpm's but the system is restricted by stock fittings and only flows 5 gpm you will not have good oil pressure, some have holes as small as 3/8" id, the internal bypass on your pump will be open and oil will never get from point a to b.
When I built my first 502 I made all those mistakes, had a stock pan, cooler and lines, oil pressure was barely 30-35 psi hot at wot, luckily I was running synthetic oil or it would have melted down. I changed everything to a size larger (even with the stock pan at the time)and I immediately had 50+ psi hot, higher flowing fittings cannot "make" oil pressure so I know that it simply wasn't flowing enough to keep up, report back with more info-Smitty

MILD THUNDER

iTrader: (3)

I would think if it was do to excessive bearing clearances, oil viscosity, oil brand, oil temps, his pressure would not immediatly shoot up when he eased off the throttles.

My guess its either a windage issue, gauge issue, or like Smitty said, a problem with the size of the stock lines/adapters.

fireboatpilot

Your engine can absolutely run oout of oil at high rpm's if there isn't enough supply in the pan to keep up with demand of the pump. If your trying to run a stock volume pan capacity on a bigger, higher reving engine, demand is up. Running at high rpm for an extended period of time keeps the pump at higher pressure. Drainback to the pan is slower than output and the pan will not be full enough to keep supply. I just went through this and had to pull my new 540's to install higher capacity pans. I was losing pressure at high rpm runs. Bigger pans, no more problem. I'm also installing Masterlube Pre-oilers this winter that will keep 4 quarts of oil on standby under pressure so that if demand at WOT is too much it will open the system and increase supply. When pressure rises again it returns to the Pre-lubers and is kept under pressure again.

stevesxm

i'm sorry but i just don't understand this... you are suggesting that you can effectively put 8 quarts of oil in suspension all inside the motor and the valve covers and not get sufficient drain down ... at 4500 rpm ? on a garden variety nothing special 540 ? sorry... no way i believe that. blue thunder ( and others ) are correct when they suggest a pan or , more likely aeration issue ...

the evidence is clear...

you know its not fittings or plumbing because only one motor did it. if it worked once, it has to work again

you know it isn't viscosity or oil brand because the load damands of a 550 hp 540 at 4500 rpm are absolutely ordinary and any good multi grade will work fine.

you know it isn't temps because the pressure come back immediatly ( as noted)

but there are some other interesting things... not the least of which is that, if i understand this all correctly, these motors have blown up before. that makes me wonder about all manner of things from the build all the way to the rigging. if something happens once and you never found why, then the chances are very good that it will happen again...

my point simply is that this 540 combo in at this level of stress and usage is a common place, no big deal thing. this isn't some 1500 hp 3 superchargers 40 psi of boost crazy thing... a bottom end / oil pressure issue here smacks of something very basic and fundemental being done wrong deep down inside and something like beating the oil into froth could very easily be the answer.

think horses... not unicorns...

fireboatpilot

i'm sorry but i just don't understand this... you are suggesting that you can effectively put 8 quarts of oil in suspension all inside the motor and the valve covers and not get sufficient drain down ... at 4500 rpm ? on a garden variety nothing special 540 ? sorry... no way i believe that. blue thunder ( and others ) are correct when they suggest a pan or , more likely aeration issue ...

I wasn't trying to say that this is his problem at 4500rpm but was simply stating that it is quite possible to run the pan out of oil "IF" the oil doesn't return to the pan quick enough to supply the pump. Yes at 80psi 6000rpm the valve covers and lifter valley can pool oil and not return it quick enough. Agreed he was not running these rpm's or psi but it is possible that there could be a restriction issue that is preventing the return. Garden variety 540? I also believe that the 55psi is quite a low cold pressure to start with. maybe just shimming the pumps up for some more pressure might help?