loosing oil presure

[sam1]

The oil presure drops with more rpm. It acts like if low on oil but it not.
Any ideas why?

[deltaAce]

Mechanical or electric gauge, oil viscosity, filter type? A boat you just got or it was o.k. till?

[sam1]

It a machanial gauge and using 20-50w oil and K&N fiter.I loses the motor last year (broken roller lifter) so it a new motor It's a 460 ford.I just charge the oil pump last week and no help.The only changes between the two engines was the cam,lifter,springs and the oil pan was made little bigger just on the upper part everything was clean and replace new(bearings,pump,ect)

[Cas]

it could be something as simple as too much oil in it. When there's too much oil, the rotating crank will foam the oil and the oil pressure will go down. Hopefully, that's all it is.

[roostwear]

Sounds kinda like the pump pickup is too close to the bottom of the pan, but from your post, it sounds like that didn't change.

[LakesOnly]

Sam:
What is your oil pressure at idle and at high rpm ENGINE COLD?
What is your oil pressure at idle and at high rpm ENGINE HOT?
What brand oil pan do you have and what is the oil capacity?
Exactly which brand and model number oil pump do you have?
Are youR main bearing shells half-grooved?
When you rebuilt the engine, did you change the brand and/or type of roller lifter used in the engine?
Have you tried changing the oil filter yet?
Please answer all these questions.
Thanks,
LO

[Moneypitt]

Did you add or have apart the lines for a remote filter? If the filter is plumbed backwards at the remote it will do exactly what you are experiencing...........MP

[Blown 472]

Stock push rods pumping the valve covers full of oil and slow drain back??

[sam1]

Ok It see if I can answer all question
It has about 60 psi hot and cold it don't charge any.
the oil pan is stock I just cut the back half and made little deeper.I could not go deeper where the pump is at .It will hit the bottom of the boat.
The pump is a Melling mel-m8ehvs
The all bearing are Clevite V series
The cam I went back to a hyd cam.No more money for a roller.
I charge the filter when I charge the pump last week
The oil lines.One come out of the side of the filter block to the outside of the oil filter and then comes out of the center and goes to the cooler and out cooler then it goes in the center for the block on the engine. I hop I didn't loose anybody on that.
The oil presure drop as soon as you start the motor and gave it the throttle. So I don't think it could be it but that didn't cross my mind
I thought I had to much oil to but I didn't charge anything on the pan thought would made a differents to the dipstick.Because the dipstick goes down in pump area and it wasn't charge any.
If the the oil lines are backward it won't have any pressure right??
I hop i answer all question
Thank you all for helping me on this problem

[Moneypitt]

the the oil lines are backward it won't have any pressure right??
If they're backward it will have pressure until you rev it up, then it will fall and come back up when you let off. It sounds like the lines are right, but double check it. Did you change filter brands? The little rubber flappers in the filter inlet are there to prevent the filter from draining out when the engine is off and the filter is mounted sideways or upside down. They block off the filter outlet (actually the inlet) if plumbed backward...........MP

[LakesOnly]

Sam,
We're going to do some point-to-point oil pressure analysis.
http://www.***boat.com/image_center/data/500/350Front_PassGal1.jpg
At the front of the block, there is an oil pressure port that is plugged with an NPT plug as pointed out by the orange arrow (disregard the blue arrow). Remove that plug by the orange arrow and install an oil pressure gauge at that location and take a reading. The pressure reading at this location is downstream of the oil pump & filter, but before the main, lifters, etc. (in other words, before any "leaks" in the oiling system).
Try this with a known accurate gauge, and other than the one that is currently installed into the engine block (unless you have already proven that the current gauge is working correctly). Your oil pressure at this location may be normal, or it may behave the same, or the symptoms may be similar but not as pronounced.
Start the engine and carefully observe and interpet the oil pressure gauge readings and post observations. (Also, try installing the known working oil pressure gage at the standard location, too, or have two identical gauges installed, one at each location, and observe behavior)
LO

[Havasu47]

MP, you are correct. If the oil flows backwards through the filter, it will give low PSI readings. Different types of filters will give different pressure readings, but it will generally be low.

[sam1]

lakesonly I can't get to that plug without pulling the motor so I put another gage on the side the block next to the filter area.It was a old gage but it works.So I had both gages on the same time.when I start the motor the new gage jump up to 62 psi and stayed and it has only 6 ft of hose.Then the old gage that is a Auto meter and it was real slow on moving up but only read 58 psi and it has around 15 ft of line.Then I switch them around and they did the same thing.So I don't know if have bad gage or a bad line or the line is to long.
So what you think Motor or gage

[QuickJet]

The oil presure drops with more rpm. It acts like if low on oil but it not.
Any ideas why?
I had the same problem with a BBC in a jet. I installed a windage via reccomendations of some board members and it cured the problem right up.

[LakesOnly]

lakesonly...I put another gage on the side the block next to the filter area. It was an old gage but it works. I had both gages on the same time. When I start the motor, the new gage jump up to 62 psi and stayed and it has only 6 ft of hose. Then the old gage that is a Auto meter and it was real slow on moving up but only read 58 psi and it has around 15 ft of line.Then I switch them around and they did the same thing. So I don't know if have bad gage or a bad line or the line is to long.
So what you think Motor or gage Sam, your post is filled with ambiguity.
Do you mean to say that you had 62 psi at the front port and 58 psi at the rear port? And, when you switch gages, you still have 62 psi at the front port and 58 psi at the rear port? Answer this question, please.
And what about the peculiar oil pressure symptoms??? What happens to oil pressure at the front port when you give the motor throttle??? Does it still drop in PSI just like the rear port gauge? How does oil pressure behave there?
LO
p.s. I uploaded a new photo in my post above and re-explained the instructions; hopefully you actually did as I instructed above.