It sounds to me that you have too much blow by causing too much air blowing out of the breathers NOT too much oil under the valve covers.

That's what I thought originally but after talking to Baxter racing he told me to run it hard and pull it back to an idle and if the pressure drops off then the pan is empty. All 16 cylinders tested exactly the same psi and both run great. The issue only arises over 5500rpm. Theyve done it since day one and he says I don't need the high volume pump. I'm almost thinking the standard pressure standard volume pump along with a 14 quart pan would be the best way to start

R,
Here's a pic of the bulldog pan, just an FYI

a high volume pump will not suck an 8 qt pan dry UNLESS the pickup is too high in the pan or the system is low on oil to begin with.i like a 10 qt pan or more but 8 qt will work.

Well, if the pan is empty the pressure would drop at high RPM also. I don't see what pulling the throttles back would do. Did he install lifter valley screens? If so, pull the intake and ditch them. I have a friend that has the same pressure issue.

What was the oil psi right before you backed off ? ie: end of the 2 min 6000rpm run ?

What was the oil psi right when you backed off to idle ?

What did it go back to after just under a minute at idle ?

Whoa. I'm confused.

So you are getting no pressure after a hard run at idle?

Here's my general advice on this topic, since I know a little about your engines.

HP500's with 420 Megablowers, intercoolers, new pistons during rebuilds to lower compression.

What I would do, and it may not be right, or even needed, but its just my opinion...

Install real oil pans, that have some sort of oil control built into them, with the proper pump pickup installed and distance to bottom of pan. Lose every single remote oil line and fitting, in favor of at least -10 lines and full flow fittings, to and from the coolers, and of course good oil coolers if you don't already have them. I think that once you get into the 800hp 6000RPM territory, the stock stuff becomes somewhat marginal. I dont think simply doing this would solve your problem you are having here, but I think its just a good route to go in general.

As far as the oil blowing out of the breathers, of course that could mean a crappy ring seal. But not sure what kind of breather system you have, or how much oil is actually blowing out, etc. As for the low oil pressure at idle after a hard run, to me that would be one of two things. Either superheated oil temperatures, or, simply too much bearing clearance.

This foam you speak of, are you sure this isnt water in the oil kind of foam??

As Mike said a HV pump should not suck an 8qt pan dry. The HV pump pumps way more oil than the motor can handle so it just by-passes the oil back into the pan. If you did a compression test that is not going to tell you much about the machining of the cylinders or ring seal. Need to do a leak down test. As Mild stated in his post your oil could be getting superheated and loosing oil pressure. If you changed the horsepower of the motor and are still using the hp500 oil cooler I can assure you the oil is getting to hot. I've seen pressure drops on stock 500's after long runs. The cooler/lines are pretty much maxed out. Whatever race engine gurus you have been talking to about your issue don't sound like they have a clue. Most gurus don't when it comes to marine engines.

Yup, bearing clearances, oil temp (huge factor !),a and oil type. ooops, did I just say that ? I'll put on my helmet and go sit in the corner.


Edit in: I agree with every reply in this thread.

Could you please elaborate on oil type so we are all clear what oil we need to run...