terryd
NAXJA Forum User
- Location
- Elk Creek/Covington Va
I dont know how many of you build motors or even know much about them for that matter. I'm coming from a back ground of working on cars and building motors all my life. My dad and his ex-brother-in-law campaigned a 500cid Hemi powered Challenger to many wins in the 70's and has been building motors since the early 70's. Now that that's out of the way, here goes.....
High Volume vs. High Pressure
In an engine, oil pressure is created by the clearances between the crank, rods, cam, lifters, and the bearings/surfaces they run on. Manufactures have specific tolerances they require for these clearances to create the proper oil pressure for the motor and provide the proper lubrication to the system.
A high volume pump moves more oil through the system, creating more pressure. At the same time, it also places increased loads on the timing set, camshaft, distributor gear/shaft, and a few seals. A high volume pump (with the exception of a situation where increased flow is needed such has a turbo charger or super charger that require pressurized lubrication) is just a crutch for an inexperienced or incompetent engine builder. Most of the excess oil is dumped back into the oil pan through the pressure relief valve creating more heat in the motor and decreasing the life of the oil/seals.
A high pressure pump is a OEM volume pump that uses a stronger pressure relief spring to hold higher pressures rather than cutting out and dumping it in the oil pan. These are recommended and used by the OEM's for high performance use. This type pump was used in the Z28 Camaro's 302 and LT1 350 in the late 60's and early 70's.
Most engines do not have the capability to return the excess oil a high volume pump moves to the top end (ie cylinder head/lifter galley) and during use at high RPM or off camber the engine can starve for oil and destroy its self. Also, in some applications (Ford most notably) the excess stress added to the system can cause it to break the oil pump drive and leave you stranded without any oil pressure. The excess oil running out of the engine onto the crank shaft and out of the bearings also causes power loss due the the oil hitting the crankshaft and creating excess "windage" and aeration of the oil, reducing the lubricity of the oil. Alot of guys use them in race motors, but at the same time, using mechanical lifters and oil restrictors to limit the oil getting to the lifters and top end, further reducing the oil volume demands of the engine.
There are exceptions to this, as before mentioned. A turbo or super charger that requires pressurized lubrication from the engine and tapped off in the proper location is a good example of a need for a higher volume.
In closing, just remember, if someone says they have a high volume oil pump, they probably dont know what they are talking about in the first place.
:rant off:
High Volume vs. High Pressure
In an engine, oil pressure is created by the clearances between the crank, rods, cam, lifters, and the bearings/surfaces they run on. Manufactures have specific tolerances they require for these clearances to create the proper oil pressure for the motor and provide the proper lubrication to the system.
A high volume pump moves more oil through the system, creating more pressure. At the same time, it also places increased loads on the timing set, camshaft, distributor gear/shaft, and a few seals. A high volume pump (with the exception of a situation where increased flow is needed such has a turbo charger or super charger that require pressurized lubrication) is just a crutch for an inexperienced or incompetent engine builder. Most of the excess oil is dumped back into the oil pan through the pressure relief valve creating more heat in the motor and decreasing the life of the oil/seals.
A high pressure pump is a OEM volume pump that uses a stronger pressure relief spring to hold higher pressures rather than cutting out and dumping it in the oil pan. These are recommended and used by the OEM's for high performance use. This type pump was used in the Z28 Camaro's 302 and LT1 350 in the late 60's and early 70's.
Most engines do not have the capability to return the excess oil a high volume pump moves to the top end (ie cylinder head/lifter galley) and during use at high RPM or off camber the engine can starve for oil and destroy its self. Also, in some applications (Ford most notably) the excess stress added to the system can cause it to break the oil pump drive and leave you stranded without any oil pressure. The excess oil running out of the engine onto the crank shaft and out of the bearings also causes power loss due the the oil hitting the crankshaft and creating excess "windage" and aeration of the oil, reducing the lubricity of the oil. Alot of guys use them in race motors, but at the same time, using mechanical lifters and oil restrictors to limit the oil getting to the lifters and top end, further reducing the oil volume demands of the engine.
There are exceptions to this, as before mentioned. A turbo or super charger that requires pressurized lubrication from the engine and tapped off in the proper location is a good example of a need for a higher volume.
In closing, just remember, if someone says they have a high volume oil pump, they probably dont know what they are talking about in the first place.
