1987 4.3l 205 high oil pressure

[Scott Danforth]

there is a pressure relief spring in the pump. this governs pump pressure

the filter relief determines the pressure drop across the filter. that relief is usually either an 11 psi or a 30 psi relief.

 

[solar7647]

Is there anything in the filter location like in my pic? Is it plugged like mine or something else there?

Its not plugged and has the filter bypass valve

 

[alldodge]

Oh well I'm out of thoughts.
100 psi with pump bypass and filter bypass. Might be time to contact ATK and ask why

 

[solar7647]

Oh well I'm out of thoughts.
100 psi with pump bypass and filter bypass. Might be time to contact ATK and ask why

Well now with the new standard pump I'm about 50psi at idle, about 65 at 2k rpm and about 75psi at about 4k rpm. So spec according to the manual is 35-55 at 2k. So I'm gonna call ATK tomorrow and make sure I can run at those numbers and maybe once the bearing wear in they come down.

 

[alldodge]

I would bet the journals are to tight

 

[solar7647]

Oh well I'm out of thoughts.
100 psi with pump bypass and filter bypass. Might be time to contact ATK and ask why

Well now with the new standard pump I'm about 50psi at idle, about 65 at 2k rpm and about 75psi at about 4k rpm

 

[solar7647]

A little snap of the oil pressure from idle to about 4k rpm

 

[Scott Danforth]

Well now with the new standard pump I'm about 50psi at idle, about 65 at 2k rpm and about 75psi at about 4k rpm

once the oil is warm that will come down

 

[solar7647]

once the oil is warm that will come down

Yeah that's what I'm hoping added with actually getting it on the water under load for the break in time. Once the bearings get a little wear on them.

 

[solar7647]

I know one thing for sure I do not want to ever have to pull the lower end apart while it's still in the boat again lol. I made the bilge bigger to allow more access to the lower end but man are my arms scratched up and sore.

 

[alldodge]

Well now with the new standard pump I'm about 50psi at idle, about 65 at 2k rpm and about 75psi at about 4k rpm

Something is wrong, by my opinion

 

[Scott06]

Something is wrong, by my opinion

Agreed clearances are too tight which wont hold up very long.

 

[SternDriveEd]

To be clear about the relief spring in the alldodge pic of an oil filter mounting base - which shows the oil filter BY PASS VALVE. It’s job is to allow for oil circulation around a totally plugged up oil filter. Better to get dirty oil delivered to the engine than to have no oil at all. The OIL PRESSURE RELIEF VALVE that is the focus of this discussion is typically located in the body of the oil pump itself. It dumps oil back into the oil pan if the oil pump is attempting to deliver excessive oil pressure to the engine.

 

[alldodge]

To be clear about the relief spring in the alldodge pic of an oil filter mounting base - which shows the oil filter BY PASS VALVE. It’s job is to allow for oil circulation around a totally plugged up oil filter. Better to get dirty oil delivered to the engine than to have no oil at all. The OIL PRESSURE RELIEF VALVE that is the focus of this discussion is typically located in the body of the oil pump itself. It dumps oil back into the oil pan if the oil pump is attempting to deliver excessive oil pressure to the engine.

Ahhh no

 

[solar7647]

Something is wrong, by my opinion

Well the 4.3l 205 Merc manual #7 lists only a min oil pressure at idle of 4psi and an oil pressure at 2k rpm at between 35 and 55 psi. So I'm only 10 psi off from the only firm spec they give. I'm more comfortable with that then I was with my readings with the high volume pump that the block came with. I am getting good flow through my lifters and onto my rockers. As it warmed as I tested the idle pressure dropped to about 46-48. I'm going to call ATK tomorrow and see what they have to say about those numbers and I'm hoping I'm good to go and they will be one more normal after my break in period. I know my old engine ran about 40psi at idle and I can't say I every noticed what it was at higher rpm. I do know that engine was 30+ years old and had extremely bad blow by in 2 cylinders along with other internal issues.

 

[dave8311]

The engine oil filter bypass valve, also known as an oil pressure relief valve, allows oil to pass through to the engine if the oil filter becomes clogged, or if the oil is too thick from being cold. This helps prevent oil starvation and engine damage. It is important to regularly change your oil according to your vehicle's maintenance schedule. This can help minimize sludge buildup that may cause the bypass valve to stick. A stuck open valve may cause a lack of oil pressure that can cause serious engine damage. A stuck closed valve may damage the oil filter, oil filter gasket, or even blow the oil galley plugs in the engine.

 

[solar7647]

So i just got off the phone with an ATK tech and we had a pretty lengthy conversation, covered all of my numbers between the standard and HV pumps and I got the green light to run her. We discussed bearing tolerances and he looked up some specs for the rebuild and says there should be no issues. So tomorrow time and weather permitting I'm gonna get it in the water and see how she reacts under load. I will be sure to post the results good or bad so that this thread has some kind of resolution, because it grinds my gears when I search and read through a thread and there was never a resolution posted lol

 

[alldodge]

What did they say about putting a HV pump in the motor?

 

[solar7647]

What did they say about putting a HV pump in the motor?

They said they always send them with all their engines but nothing on the pressure. The discussion was focused on that I installed a standard flow pump and those numbers.

 

[alldodge]

They said they always send them with all their engines but nothing on the pressure. The discussion was focused on that I installed a standard flow pump and those numbers.

Acknowledge but then evade the question. Things that would make me go hummm