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techtalk:evo:oil01 [2024/02/05 02:13] – [1992-2003 engines] hippysmack | techtalk:evo:oil01 [2024/02/21 18:53] (current) – [Engine Oil Pressure and Testing] hippysmack | ||
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That page consists of where to test, expected oil pressure for the respective year models and a link to the page for installing a pressure gauge. \\ | That page consists of where to test, expected oil pressure for the respective year models and a link to the page for installing a pressure gauge. \\ | ||
- | On Evo engines, 20% of oil pressure is sent to the bottom end and 80% is sent to the top end according to MMI documents. ((2000 MMI Documents)) | + | The FSMs say the oil pump is non-regulatory and delivers its entire volume of oil under pressure to the motor. But that is not the entire story. \\ |
- | As the engine warms to normal operating temperature, | + | |
- | Basically, oil that can't flow as fast builds more pressure and oil that flows faster builds less pressure. | + | |
- | Also,when an engine is operated | + | **Cold oil flows slower and at higher pressure than hot oil**. During start-up |
- | **Restrictions in the oil path harness and manipulate the pressure created at the pump**. Pressure is always greatest at the oil pump outlet. | + | **The oil path, as designed, creates variable system pressures**. The restrictions in the oil feed path (hose size, routing paths, orifice sizes, etc) manipulate oil flow and oil pressure. Each restriction in the feed path, whether chamber size, bends or orifice size, lowers the flow volume and pressure downstream of the restriction. I.E., A restrictor in the end of the pinion shaft will lower the amount of oil that gets passed it to the crankpin/ |
+ | |||
+ | **Restrictions in the oil path harness and manipulate the pressure created at the pump**. Pressure is always greatest at the oil pump outlet. | ||
+ | |||
+ | **Oil volume to the motor is dependent on pump capabilities and RPM**. When an engine is operated at higher speeds; the volume | ||
+ | |||
+ | ==== Oil Pressure Light ==== | ||
+ | If the oil pressure light stays on at speeds above idling, always check the oil supply first. \\ | ||
+ | Then if the oil supply is normal, look inside the oil tank to determine if oil is returning to the tank from the return hose with the engine running. \\ | ||
+ | If oil is returning to the tank, there is some circulation and the engine may be run a short distance if necessary. \\ | ||
+ | If no oil is returning, shut the engine off until the trouble is located and fixed. \\ | ||
+ | |||
+ | Conditions causing the oil light to stay on; \\ | ||
+ | Low or diluted oil supply, \\ | ||
+ | Or a plugged lifter screen (86-91) under the plug between the tappets, \\ | ||
+ | A grounded oil signal switch wire, \\ | ||
+ | Faulty oil switch, \\ | ||
+ | Faulty or weak oil pump, \\ | ||
+ | Clogged feed hose (in freezing weather from ice and sludge preventing the circulation of oil). \\ | ||
- | **The oil path, as designed, creates variable system pressures**. The restrictions in the oil feed path (hose size, routing paths, orifice sizes) manipulate oil flow and oil pressure (which is normally measured with a PSI gauge). \\ Each restriction in the feed path, whether chamber size, bends or orifice size, lowers the flow volume and pressure downstream of the restriction. | ||
===== Year Model Specifics ===== | ===== Year Model Specifics ===== | ||
Refer to the drawings at the top of this page from the text below. \\ | Refer to the drawings at the top of this page from the text below. \\ | ||
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* [[techtalk: | * [[techtalk: | ||
- | See also [[techtalk: | + | See also in the REF section of the Sportsterpedia: |
+ | * [[techtalk: | ||
+ | | ||
The oil pressure switch (for the oil light) is a pressure actuated diaphragm type on / off switch basically. \\ | The oil pressure switch (for the oil light) is a pressure actuated diaphragm type on / off switch basically. \\ | ||
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|{{: | |{{: | ||
- | ===== Oil Pressure Light ===== | ||
- | If the oil pressure light stays on at speeds above idling, always check the oil supply first. \\ | ||
- | Then if the oil supply is normal, look inside the oil tank to determine if oil is returning to the tank from the return hose with the engine running. \\ | ||
- | If oil is returning to the tank, there is some circulation and the engine may be run a short distance if necessary. \\ | ||
- | If no oil is returning, shut the engine off until the trouble is located and fixed. \\ | ||
- | |||
- | Conditions causing the oil light to stay on; \\ | ||
- | Low or diluted oil supply, \\ | ||
- | Or a plugged lifter screen (86-91) under the plug between the tappets, \\ | ||
- | A grounded oil signal switch wire, \\ | ||
- | Faulty oil switch, \\ | ||
- | Faulty or weak oil pump, \\ | ||
- | Clogged feed hose (in freezing weather from ice and sludge preventing the circulation of oil). \\ | ||
===== Oil Check Valve (77-E87)===== | ===== Oil Check Valve (77-E87)===== | ||
See [[techtalk: | See [[techtalk: | ||
- | The Oil Check Valve is located behind the threaded filter adapter in the center of the oil filter mount. The filter adapter I.D. was enlarged on the filter end to accept the check valve. The check valve operation is dependent on receiving filtered oil (through the filter media) to lift the check valve cup and allow oil to pass. Therefore, a stopped up oil filter media condition (not allowing flow or enough flow) may not produce enough oil pressure to open the check valve before the filter bypass opens. \\ | + | The Oil Check Valve on 1986-E1987 engines |
- | **The oil pump check valve plays a role in the operation of the oil pressure switch**. \\ | + | **The oil pump check valve plays a role in the operation of the oil pressure switch**. \\ |
+ | It adds additional restriction in the feed path which raises the oil pressure in the chamber feeding the switch. \\ | ||
|{{: | |{{: | ||
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This reduction in pressure is also sensed by the oil pressure switch. When the pressure drops, the diaphragm eases back toward the closed position. If the pressure is low enough, the contacts will close or partially make contact while closing or intermittently opening and closing. The oil light will come on or flicker depending on the action of the contacts. \\ | This reduction in pressure is also sensed by the oil pressure switch. When the pressure drops, the diaphragm eases back toward the closed position. If the pressure is low enough, the contacts will close or partially make contact while closing or intermittently opening and closing. The oil light will come on or flicker depending on the action of the contacts. \\ | ||
- | The pressure switch requires no back pressure from the engine to stay open. It opens solely from the pressure generated from the oil pump with the assistance of the check valve to hold some of that pressure in the pump. So, it is possible but not likely to have a stuck closed check valve with no oil light on. \\ | + | The pressure switch requires no back pressure from the engine to stay open. It opens solely from the pressure generated from the oil pump with the assistance of the check valve to hold some of that pressure in the pump. \\ |
===== Oil Check Ball (L87 and Up) ===== | ===== Oil Check Ball (L87 and Up) ===== | ||
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| Check Ball (26437-86A) L87-91 \\ (replaced by (26437-86B) ) ((photo by Hippysmack)) | | Check Ball (26437-86A) L87-91 \\ (replaced by (26437-86B) ) ((photo by Hippysmack)) | ||
- | ====== Wet Sumping / Sit Sumping ====== | + | |
- | See article on [[techtalk: | + | |
\\ | \\ |