Merc Oil pump

[G_Hipster]

Am I correct in assuming a 5.7 Vortec has a Hv oil pump?

 

[achris]

No. Standard pump. You only need high volume when teh engine is designed to run in excess of about 6,000rpm. Boat engine should never get beyond about 4800....

Chris.....

 

[G_Hipster]

Ok Thanks.

 

[Scott Danforth]

They do use the heavy duty oil pump as the truck motors.

 

[Bt Doctur]

Never use a Hi-Vol pump with anything less than a 12 Qt oil pan.

 

[Scott Danforth]

Never use a Hi-Vol pump with anything less than a 12 Qt oil pan.

I disagree with that statement. the oil pump regulator will only provide enough oil to the engine to satisfy the pressure requirement of the regulator spring setting. excess oil is put back to the oil pickup side. its how the oilpump with internal regulator works.

myths about emptying the sump are just that, myths. unless the bearings are gone and the regulator is stuck closed, that scenario just doesnt happen

however for a stock build, high volume is not needed

cut-n-pasted from engine builder's site

Increases in the engine's oil requirements come from higher RPM, being able to rev faster, increased bearing clearances, remote oil cooler and/or filter and any combination of these. Most high volume pumps also have a increase in pressure to help get the oil out to the bearings faster.

That is what a high volume pump will do. Now let Is consider what it will not do.

1. It will not replace a rebuild in a worn-out engine. It may increase pressure but the engine is still worn-out.

2. It will not pump the oil pan dry. Both solid and hydraulic lifters have metering valves to limit flow of the oil to the top of the engine. If a pan is pumped dry, it is because the holes that drain oil back to the pan are plugged. If the high volume pump is also higher pressure, there will be a slight increase in flow to the top.

3. It will not wear out distributor gears. The load on the gear is directly related to the resistance to flow. Oil pressure is the measure of resistance to flow. The Ford 427 FE "side oiler" used a pump with relief valve set at 125 psi and it used a standard distributor gear. Distributor gear failures are usually caused by a worn gear on a new cam gear and/or worn bearings allowing misalignment.

4. It will not cause foaming of the oil. With any oil pump, the excess oil not needed by the engine is recirculated within the pump. Any additional foaming is usually created by revving the engine higher. The oil thrown from the rod bearings is going faster and causes the foaming. This is why high performance engines use a windage tray.

5. It will not cause spark scatter. Because of the pump pressure there is a load on the distributor gear. The number of teeth on the oil pump gears determine the number of impulses per revolution of the pump. In a SB Chevy there are seven teeth on each gear giving 14 impulses per revolution. At 6000 RPM the oil pump is turning 3000 RPM or 50 revolutions per second. To have an effect on the distributor, these impulses would have to vibrate the distributor gear through an intermediate shaft that has loose connections at both ends. Spark scatter is usually caused by weak springs in the points or dust inside the distributor cap.


High volume pumps can be a big advantage if used where needed. If installed in an engine that does not need the additional volume, they will not create a problem. The additional flow will be recirculated within the pump.

 

[G_Hipster]

They do use the heavy duty oil pump as the truck motors.

I thought they were Hv pumps as most trucks and the 5.0 in my boat I always saw about 40-45 psi. Car engines 30-35 warm. I have a pump NIB that has a relief spring to change it was the main reason for asking.

 

[G_Hipster]

I disagree with that statement. the oil pump regulator will only provide enough oil to the engine to satisfy the pressure requirement of the regulator spring setting. excess oil is put back to the oil pickup side. its how the oilpump with internal regulator works.

myths about emptying the sump are just that, myths. unless the bearings are gone and the regulator is stuck closed, that scenario just doesnt happen

however for a stock build, high volume is not needed

cut-n-pasted from engine builder's site

Increases in the engine's oil requirements come from higher RPM, being able to rev faster, increased bearing clearances, remote oil cooler and/or filter and any combination of these. Most high volume pumps also have a increase in pressure to help get the oil out to the bearings faster.

That is what a high volume pump will do. Now let Is consider what it will not do.

1. It will not replace a rebuild in a worn-out engine. It may increase pressure but the engine is still worn-out.

2. It will not pump the oil pan dry. Both solid and hydraulic lifters have metering valves to limit flow of the oil to the top of the engine. If a pan is pumped dry, it is because the holes that drain oil back to the pan are plugged. If the high volume pump is also higher pressure, there will be a slight increase in flow to the top.

3. It will not wear out distributor gears. The load on the gear is directly related to the resistance to flow. Oil pressure is the measure of resistance to flow. The Ford 427 FE "side oiler" used a pump with relief valve set at 125 psi and it used a standard distributor gear. Distributor gear failures are usually caused by a worn gear on a new cam gear and/or worn bearings allowing misalignment.

4. It will not cause foaming of the oil. With any oil pump, the excess oil not needed by the engine is recirculated within the pump. Any additional foaming is usually created by revving the engine higher. The oil thrown from the rod bearings is going faster and causes the foaming. This is why high performance engines use a windage tray.

5. It will not cause spark scatter. Because of the pump pressure there is a load on the distributor gear. The number of teeth on the oil pump gears determine the number of impulses per revolution of the pump. In a SB Chevy there are seven teeth on each gear giving 14 impulses per revolution. At 6000 RPM the oil pump is turning 3000 RPM or 50 revolutions per second. To have an effect on the distributor, these impulses would have to vibrate the distributor gear through an intermediate shaft that has loose connections at both ends. Spark scatter is usually caused by weak springs in the points or dust inside the distributor cap.


High volume pumps can be a big advantage if used where needed. If installed in an engine that does not need the additional volume, they will not create a problem. The additional flow will be recirculated within the pump.

I agree with this, Any time I've ever seen an issue was at the track. Guys running an HV with a 4qt car pan and turning them to 6.5k

 

[MBAKER]

Like others have said, its just a standard volume pump but is the 3/4 pickup tube not the 5/8 like the pre vortech engines. Ultimate running pressure is determined by amount of oil supplied and resistance to flow (think bearing clearance). With correct bearing clearances the standard pump will still put out 60-65 psi at higher rpms. Either way the pumps have a relief spring that limits ultimate pressure to about 65psi typically, but if a standard pump supplies enough oil to hit the relief spring a higher volume pump is only going to run more oil through the bypass not the engine. Typically once warmed up you will see about 15 at 600rpm idle maybe 40-45 at 2000-3000 rpm and should approach 60 at higher speeds. If you have slightly bigger bearing clearances leaking oil inside the engine then a HV pump can help.

For what its worth, when we ran circle track cars, we ran a +10% pump (typical HV pumps are 25%) up to 8000 rpm with a 6qt pan and never had problems with oil pressure or running the pan dry. The key is drainback. Yes they can move oil to the top, you just need to make sure it has room to get back to the sump as fast as possible.

The best part is that the small block Chevy engine is solid and doesn't need lots of oil pressure. Ive seen them run 30 lap circle track races at 8000 rpm with a max of 30psi. In general if you have 10psi at idle and it goes up some when you rev it up chances are you will run a long time.

 

[G_Hipster]

Like others have said, its just a standard volume pump but is the 3/4 pickup tube not the 5/8 like the pre vortech engines. Ultimate running pressure is determined by amount of oil supplied and resistance to flow (think bearing clearance). With correct bearing clearances the standard pump will still put out 60-65 psi at higher rpms. Either way the pumps have a relief spring that limits ultimate pressure to about 65psi typically, but if a standard pump supplies enough oil to hit the relief spring a higher volume pump is only going to run more oil through the bypass not the engine. Typically once warmed up you will see about 15 at 600rpm idle maybe 40-45 at 2000-3000 rpm and should approach 60 at higher speeds. If you have slightly bigger bearing clearances leaking oil inside the engine then a HV pump can help.

For what its worth, when we ran circle track cars, we ran a +10% pump (typical HV pumps are 25%) up to 8000 rpm with a 6qt pan and never had problems with oil pressure or running the pan dry. The key is drainback. Yes they can move oil to the top, you just need to make sure it has room to get back to the sump as fast as possible.

The best part is that the small block Chevy engine is solid and doesn't need lots of oil pressure. Ive seen them run 30 lap circle track races at 8000 rpm with a max of 30psi. In general if you have 10psi at idle and it goes up some when you rev it up chances are you will run a long time.

I did a little more research last night. The pump I have is a 5/8 pickup high pressure not HV pump. Melling m55-a or something. I'm going to get a standard 3/4 pickup pump to go on it. From what I've read the 5/8 th's pickup pumps can start to cavitate when running 4500+ rpm's for extended periods. Thought I was going to be able to use something I had sitting on the shelf, but not this time.

Thanks for all the input guys.

 

[MBAKER]

The m55a is a standard volume high pressure pump. The relief spring in the 55a is set to 75psi +/- whereas the 55 is around 60 psi. You said you had another spring if I remember right, that's likely the 60psi spring anyway, if you change it you are back to a M55.

I wouldn't worry about the 5/8 pickup if you wanted to use it, just make sure the pickup is right for the pan and set at the right height off the pan floor.

 

[G_Hipster]

The m55a is a standard volume high pressure pump. The relief spring in the 55a is set to 75psi +/- whereas the 55 is around 60 psi. You said you had another spring if I remember right, that's likely the 60psi spring anyway, if you change it you are back to a M55.

I wouldn't worry about the 5/8 pickup if you wanted to use it, just make sure the pickup is right for the pan and set at the right height off the pan floor.

Gotcha, yes the pump came with a little packet that contains the standard spring, a roll pin and a plastic collar for the pump shaft, and destructions to change it back to a standard pressure pump. Millions of engines have survived with a 5/8 pump so.....

 

[G_Hipster]

Sounds ridiculous, but I bought this boat last year, and used it 3 times before seeing metal in the oil. Ran well on trial, but digging through the paperwork it had been "stuck" at one point. Upon dis-assembly it needs new manifolds and risers also. The block is a clean truck block, .010/.010 crank, re-ring new cam and bearing etc. New Gm vortec heads. Way over budget.