I just finished a build of a 460, all new bearings, melling HV oil pump, 10 quart Milodon marine oil pan and pickup K&N oil filter.  Everything is new in this motor but the crank.  All clearances were checked and fine.

The issue is the motor holds 75 PSI of oil pressure till it gets to about 4500 RPM's.  That is where the problem comes in, it then drops to 20 PSI??

I know you guys have experiance with the oil pan so I'm posting this here.   I have a guy telling me the Milodon oil pan is the problem.  He thinks the oil is being sucked up by windage from the crank thus draining the pan? 

I'm thinking the oil pump may be defective, or an air leak in the pick up.  I'll be checking both when I pull the engine.

This thing runs great and sounds great.  I have not run it above the point where the oil pressure starts to falter.  This is all happening IN the water.   The pressure drops comming out of the hole and when sneaking up on 4600 on a glass smooth lake.

I can't see sloshing being an issue except when pulling up on plane.

 what do you guys think?   I ordered a new pump.

What do you guys think?  Have you ever heard of this before?

Pick up is 3/8 inch from the bottom, oil is castrol 10-40

I have close 400 bucks in this setup with pump, pickup etc.  I would rather fix this pan if possible.

 Does anyone know what the problem is with these pans if any?  It's hard to imagine that they are mass producing a faulty product.   Is there just a component in some of them that could be corrected?

My wife is understanding but not to the tune of throwing away 400 bucks just to buy another brand.... if you know what I mean 

Is the problem in the trap door area or what?   

I put in 10 quarts and checked it with the dipstick.  It's at the normal (old pan) level with the 10 quarts.

If it were the oil level it wouldn't return pressure immediatley after cuting back rpms by as little as 500.  It would still have to settle I would think.

I'm leaning toward the pump cavatating possibly due to the pressure relief valve NOT opening.
What do you think?

Im really just kicking around any ideas at this point. 

If it were a bearing it would be bad through out the rpm band.  It just acts like someone turns a switch at 4500 rpm and as soon as you drop below that the pressure comes right back.   That's why I suspect something in the pump as being defective.

I have a new pump on the way but after reading so may posts that say it may be the pan I just don't know.

   I have a message in to Armondos to see what they think also.

the factory markings on the dipstick are now useless unless you know how many quarts to the bottom of the windage tray, windage tray is in a different location from stock.

for example with my armondos pan i run it just below the low mark on the dipstick. remove 1-2quarts from the pan and test. its cheeper than a new pump,

This isn't agruing with anyone, this is a brain storming session to develop any possibilities we can come up with.
I've been building motors for a long time and have NEVER come across anything like this.
Sorry if I offended you, but thank you for your input
Dave

Could you tell me where the issue is with this pan?  I could modify it if need be.   I just need to know what part needs fixed.

Thank you, that's something to work with.  By any chance does anyone have a picture of
the INSIDE of some of the other pans?   If so please e mail them to me at

mysticowner99@msn.com

I just got off the phone with the tech rep for Milodon and he thinks it's an oil pump bypass issue.
He also told me to drop one or two quarts of oil and try that to make sure it isn't aireated oil

 I'll try lowering the oil level next weekend and check the pressure with the new mechanical gauge. 

 If it still drops I'll pull the pan, check the doors etc and look over the possibility of more baffeling to direct the oil to the gate.  I'll make sure the gaskets are ok and not sucking air.

I'll put in the new oil pump at that time too.

Any other ideas of what to look for?

I'm leaning toward the pump cavatating possibly due to the pressure relief valve NOT opening.
What do you think?

HUH? Oh, this  is a good one.  Please explain to me how the bypass NOT opening is causing your sending unit to register less oil pressure....even if the pump is "cavitating" with a shut bypass piston.....

LO

By any chance does anyone have a picture of the INSIDE of some of the other pans? 

If you are considering looking at different baffling approaches in the interest of applying them to the Milodon pan, then you should know that proper gating and baffling for one brand/type oil pan is not correct for another band/type.

LO


p.s. Could it be an air leak? Yes. Could it be a gasket leak? Yes. Could it be a bad pump? Yes.  It could be several things, based on your symptoms.   It could even be a cracked engine block.  Most of these possibilities (and many others) are unlikely...but certainly possible.  BUT I doubt it is any of those things.

Like I said in the other thread on the other forum, I run a Milodon pan.  I like Milodon components; I think they are quality.  My previous engine used Milodon Pan, Milodon timing chain, Milodon rod bolts, Milodon stainless valves, etc., you get the picture.  No disrespect to them.  All custom build engines are different and you need to tend to each engine's needs, one pan does not fit all, nor does a piston, a rocker arm, etc.

Apparently I'm the only one in this thread that has come across a bad gauge/sending unit or   

ph-8a ? fl-1a
is the pressure relief valve bypassing in the filter?
could be plugged up with the assembley lube.
 i'de swap out the oil filter for 3 bucks , then run it.
might be a cheep fix.
if that don't fix it, might try draining some oil off.
then you will know if it is the pan.
cheep diagnosis.
the pan should be less full of oil at rpm...
less chance of windage.
you should able to get by with 6-7 quarts.
4500 rpm only needs 20 psi to live.
shouldn't hurt the engine testing it.
where are you pulling the oil pressure off of  ?
after the oil pump from the cam bearings ?

can you pull it off the main bearings like a Cleveland ?