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  • Presion de aceite VW 1.8T ( no bora jaja)

    Muchachos, una duda que tengo, cuanto es la presion normal aprox. de aceite en un motor 1.8t, nafta de surtidor? con el motor entre 70º /80º graciassssssssss

  • #2
    Re: Presion de aceite VW 1.8T ( no bora jaja)

    AEB, ATW, AWM, AUG oil presure switch should come on in 1.2 to 1.6 bar (17.5 to 26psi) range. Hence the light.

    As you realized the Bentley Service manual says normal condition the minimum oil pressure at idle should be 2 bar (30psi), and within 3 to 4.5 bar (44 to 65psi) at 2000rpm with
    hot engine. If these minimum values are not obtained: repair mechanical damage, check oil pressure valve, or replace oil pump.


    http://www.audizine.com/forum/showth...leshooting-DIY

    The AMB engine and most late model 1.8t engines use a
    Gerator style oil pump. Basically the pump has a 6 tooth gear which rotates eccentrically inside of a 7 tooth internal gear ring. (fig-11) For every 30° of pump shaft rotation a cavity is formed between the two gears and the sidewalls of the pump housing. Because the components of the oil pump are precision machined and clearances between the teeth of the gears are typically less than .075mm a vacuum is created each time a cavity is formed. The volume of this cavity is approximately 2800 mm^3 or 0.0028 liters. As the gears continue to rotate the cavity collapses forcing oil to the pump outlet.

    Click this bar to view the full image.


    For every revolution of the pump the 7 cavities are formed and collapsed, so the pump displacement per revolution is 0.019 liters. Also note that the pump is driven by a chain sprocket from the crankshaft at 70% of the
    crankshaft speed. So for every revolution of the crankshaft the theoretical displacement capacity of the pump is therefore 0.014 liters. If you multiply this by 6500 rpm our pump theoretically could move oil at a rate of 89.1 liters/min!

    All gearator pumps have a general efficiency rating which is really governed by the amount of leakage (or fluid slip) past the internal pump clearances between the gear teeth and sidewall, which reduce the overall flow. Typically this number for a new pump is 85%. Additionally the density of the fluid being pumped will also change the total amount of fluid displacement. The fluid density of 5w30 at 100dec C is 860 kg/m^3. When you take all of this into account a normal pump should be capable of flowing about 65 liters/min. (fig-12)



    It is important to note that Positive Displacement Pumps are “constant flow machines” that is they will produce the same flow at a given speed (RPM) no matter what the discharge pressure. This is the reason that the oil pump has a spring loaded ball relief valve. If the flow requirements of the engine are lower than the flow output of the pump at any given time, the additional flow bypasses the engine and is dumped straight back to the oil pan.


    Typical flow requirements for various engine components

    If you refer back to the Oil Circuit diagram (fig-3) you’ll realize there there are a lot of engine components which consume oil for lubrication and to dissipate heat. 65 individual components total!

    You can see from the chart below (fig-13) that your main bearings and rod bearings consume almost 50% of your oil pump capacity across the RPM range. It should not be surprising, considering that at 6500 RPM the total angular movement of your 5 main bearings and 4 rod bearings is about 456 ft/sec or over 5 miles in one minute! You need a lot of oil flow to lubricate these bearings surfaces.

    Click this bar to view the full image.


    If you look closely you will notice one important detail from the chart data. In this example at an engine speed around 3000 rpm the oil pressure in the system increases to the point where the required engine flow does not equal the pump flow capacity and at that point the pressure relief valve on the oil pump begins to open. Since the valve is spring loaded the amount of flow which is returned to the oil pan also increases as the rpm’s increase. The flow indicated by the striped red pattern on the upper right is just wasted pump capacity and wasted energy.

    Why is the system designed for over capacity? The simple answer is that car makers are aware that over time many factors could influence the flow requirements of the system. So there is some built in over capacity to account for those factors such as bearing wear, pump wear, oil viscosity changes, extreme temperature changes and mechanical failures. Since engine journal bearings by design only work by maintaining a continuous flowing film of oil between the rotating surfaces, the oil flow can never be interrupted during operation.

    This is a good time to reinforce the main point. Maintaining proper “OIL FLOW” throughout the lubrication system is the single most important element to achieving proper performance and longevity from
    your engine.


    Oil Pressure within the engine

    Now that we understand the flow requirements within the engine we can take a quick look at how the flow within the engine creates pressure within the system. (fig-14) In this graph you can see that oil pressure also increases as engine speed increases. Also like the chart above once the pressure relief valve begins to open above 3000 rpm the pressures begin to level off and are not proportional to engine speed.

    Click this bar to view the full image.


    Ok so if the above statement is true about pressures leveling off after the relief valve opens, then why does the pressure in the rod bearings continue to increase with engine speed. I have to say I didn’t know the answer to this either when I saw this chart, and it took some time to find the information. Basically the increase in pressure is caused by the centripetal force generated inside of the crankshaft oil gallery to the rod bearing. As crankshaft rotation increases the outward pushing force on the oil towards the rod bearing also increases.



    Section 5 - General Causes of Low Oil Pressure

    So now we can focus a bit on Oil Pressure. If flow is so important then why worry about pressure? The main reason is that it’s not easy (cost effective) to measure oil flow within the engine. So the common approach is to measure system pressure after the
    oil filter.

    Think about measuring oil pressure to diagnose engine problems as a doctor might measure blood pressure. Since a doctor cannot easily look into your veins and arteries he relies on some very easy to take measurements, usually Pulse and Blood Pressure. High or Low blood pressure is usually not the problem it’s the underlying physiological conditions which are causing the deviation from normal blood pressure which is the real problem. Since a heart is a type of positive displacement pump high blood pressure can be a symptom of some increased resistance to proper blood flow within the body.

    Getting back to our engine, high oil pressure is not really a problem in that the design of the system includes a relief bypass valve to bleed off this excess pressure as needed. However, low oil pressure is a symptom of a problem that needs to be addressed.

    Hopefully by now the relationship between flow (resistance to flow) and pressure is clear. If we look at each variable individually and isolate all other factors we can discuss all of the factors which reduce flow or increase resistance and subsequently reduce system pressure. I’ve tried to list these in order of the most common and easiest to check.

    • Low Oil Level – Pretty simple if the oil level drops below the pickup tube the pump will suck in air and the flow of oil will be reduced. If your engine is equipped with a level sensor and its working correctly you should already know this is a problem.

    • Incorrect Oil Weight – Using an oil with a lower viscosity than the system was designed for, will increase flow, but reduce backpressure. Sounds good so why not simply run lower viscosity oil. You can find some very well written information about this on the BITOG website and I recommend reading the full article when you have time. LINK

    • Oil Viscosity Too Low – In addition to using the wrong or lower viscosity oil as noted above, oil viscosity can change over the life of the oil. Contaminants such as fuel and water, soot, or intentionally adding oil treatments to the sump can lower viscosity. Additionally the longer oil is run its viscosity will be reduced as sheering forces breaking down oil molecules.

    • High Oil Temperature – Pretty basic but to be complete let’s just reiterate that oil viscosity decreases as temperature increases. (fig-15) If you look closely you will see the intersection on the graph for 5w40 motor oil at operating temperature. If your engine is running 15 degrees hotter (which is likely an entirely different problem) you oil viscosity is equivalent to 5w30 motor oil.


      Click this bar to view the full image.


    • Incorrect Oil Filter – The 1.8T oil filter has a standard ¾-20UNC threaded boss. There are thousands of filters on the shelf that would fit the housing, but the flow capacity and bypass valve specifications may be significantly different than the correct oil filter. (fig-16) Using a filter with a higher bypass (or no bypass) and or a smaller filter element can reduce flow through the filter. Pressure before the filter would be higher but flow and pressure after the filter would be lower. In the photo below I'm showing a Motorcraft filter next to the Mann W950/4. Do not use the Motorcraft filter. However the MannW950/4 is an excellent filter. It has the correct bypass rating required for 1.8t and because of it's size it adds about 1/2 qt more oil to the engine capacity, which will increase useful oil life in the engine.




      When choosing a filter keep these specifications in mind: The
      correct oil filter should have a particle filtration rating of 21 micron, bypass pressure rating of 2 to 2.5 bar (29-36 psi), flow capacity of 26 to 35 l/min (7-9 gpm).

    • Malfunctioning Crankcase Ventilation System – The crankcase ventilation system in modern engines is rather complex and the 1.8t engines have a rather convoluted and complex system comprised of over a hundred pipes, hoses, check valves ect. Without going into extensive detail here, the system is designed to direct combustion gasses which are blown by the piston rings and into the crankcase back into the intake system to be burned off. A normally working system will have slight fluctuations between pressure and vacuum which can impact oil pressure by a few psi. As crankcase pressure increases this air pressure pushes down on the oil in the pan increasing pressure into the pump. This is no big deal as a little extra psi of oil pressure isn’t going to hurt anything. When there is slight vacuum pressure in the crankcase this force sucks against the pump suction and may slightly lower oil pressure. The problem can occur if either this positive or vacuum pressure is excessive. Consider that vacuum of 28 in/hg would be equivalent to a reduction in oil pressure of about 14psi which is not insignificant. Here is a great real world example of a forum member troubleshooting this exact problem. LINK

    • Clogged Oil Pickup Screen – Most engine oil pumps have a metal tube with a screen attached to the open end. This screen is designed to keep larger particles about .5mm dia from entering the oil pump. The 1.8t pickup screen is conical in shape and has an area about 1760mm^2. That’s about 15 times larger than the main oil gallery coming from the pump into the block. So the system is designed to have a lot of excess flow capacity. However even with that excess capacity there are very specific reasons why the pickup screens on 1.8t engines are prone to clogging. (fig-17) More on this topic later in the troubleshooting section. The main issue with a clogged pickup screen is that you may not see a serious pressure drop at lower rpm's but at higher rpm's the engine may be starved for oil. However in this rpm range you would not necessary trigger a pressure warning. At higher rpm ranges the pump may try to draw more oil than then can pass through the clogged screen. In the most serious cases as the pump cavity forms the pressure inside of the chamber drops to a point where the oil actually boils this is called Cavitation. LINK


      Click this bar to view the full image.


    • Oil Pump Failure – Considering the simplicity of the Gerator oil pump failures are rare. Over time the clearance between the gear teeth and the clearance between the pump sidewalls will increase which will allow oil to slip past the pump cavities, thus reducing its efficiency and subsequent flow. This condition could be accelerated if oil is heavily contaminated with metal particles from engine damage, oil filter operating in bypass or extended oil change intervals. (fig-18-19) The reductions in pressure would be gradual. As noted previously pump wear can be accelerated due to cavitation as the small microscopic bubbles form in the pump chamber and quickly collapse. The forces are strong enough however to break down the surface of the pump gears and walls which causes pump wear. Mechanical failures could also occur such as broken chain, sprocket or sprocket key but these seem to be extremely rare.

      Click this bar to view the full image.


      Click this bar to view the full image.


    • Excessive Bearing Wear – If you have no knowledge about how engine bearings work take a minute and read the interweb. Here is a brief starterLINK. The key thing to know is that engine bearings operate in a Hydrodynamic lubrication condition. Which means that a thin film or oil separates the rotating crankshaft from the bearing surface. Engine forces like the force of combustion pressure which are typically 550-650 psi push on the rods and the crankshaft with over 6500 lbs of force. The only thing that keeps the bearing surface of he rod bearing from smashing into the crankshaft bearing journal every engine rotation is this thin film of oil!

      What maintains that thin film of oil is a constant flow from the pump. In a properly working engine, as the crank journals rotate oil is forced from he bearing cavity but more oil is ready to fill the void immediately. If there is enough flow and pressure the bearing surface should never touch the crank.

      As with oil pump wear wear is something that normally occurs gradually over time. Most wear (perhaps 90%) occurs during the first few minutes of engine start-up when the bearing journals come into contact with the bearings before the oil is up to proper temperature (ie viscosity). Even the best cared for engines will be subject to progressive wear. As the clearance between the bearings and the journals increases the restrictions to flow decrease and so does the pressure. While the main bearings are usually the first to go, rod, cam and even turbo bearings can wear and reduce overall system pressure. What is interesting to note is that increased wear reduces flow, which further accelerates wear. Eventually reduce the flow the point where the bearing is totally destroyed (fig-20-21)
      LINKLINK


      Click this bar to view the full image.


      Click this bar to view the full image.




    • Mechanical Engine Malfunction or Damage – Any element within the lubrication circuit can be broken or damaged and result in reduce system pressure. A damaged cam adjuster, or broken turbo thrust bearing would likely present other more obvious problems but they can none the less reduce flow and cause a low pressure situation. While also rare the pressure relief bypass valves in the oil pump and filter housing or even a piston oil jet could get stuck in an open or partially open position which would drastically reduce system pressure at the lower engine speeds.

    • Clogged or Blocked Oil Passages - It is rather unlikely that the main oil supply passages could be clogged but it could happen to a severely abused engine subjected to long oil change intervals. Also there is one large drain tube through the cylinder head and block which drains back into the filter housing. You can see this in section 1. (fig-4) The size of this tube is sufficiently large enough where is should not impede the return flow of oil from the head but again if the engine has significant sludge buildup it could. If oil pumped to the cylinder head cannot drain back fast enough then the oil level in the pan can drop below the pickup tube and allow the pump to draw in air which will further reduce oil flow.



    When trying to isolate the causes of low oil pressure and looking at this list it’s also important to note that many of these factors are interrelated such as oil temperature and viscosity. Also it’s very possible that an engine may have several causes of varying degrees which individually may not cause system pressure to fall below required levels, but combined have that result.



    Section 6 – How the Oil Pressure Warning System Works

    Before we move on, I need to say that this topic has been extensively and at time painstakingly explained many many times here on the Audizine forums. This section is really a copy and paste of some of those previous posts. Here are a few that I found and used when trying to diagnose my warning light problem. Thanks to walkey_talkey20 for explaining this many times.
    LINKLINKLINKLINK

    The B5/B6 1.8t engines are equipped with a simple pressure switch connected to the oil filter housing after the filter. Refer back to (fig-2#17 and fig-7) The pressure sensor is a simply switch which is normally open. When the pressure reaches approximately 23psi the electrical contacts within the switch will close. One signal wire from the switch to the
    Instrument Cluster completes the monitoring circuit to ground when the switch is closed.

    The oil pressure warning is triggered under certain conditions. The Instrument Cluster will signal a
    low pressure warning if any of the following conditions occur. The warning indicator on the dash will show a RED Oil Can. (fig-22) and you will hear three long beeps. This is not to be confused with the yellow sensor warning also shown, which is indicative of an oil level sensor failure and has nothing to do with the oil pressure.





    • Condition 1 - If the switch is closed with the engine off a warning will be triggered
      This warning is designed to let the operator know that the switch is damaged, in that it is remaining in the closed position while no pressure is actually present, or the wire connecting the switch to the Gauge Cluster is shorting to ground. This type of switch failure can be confirmed by removing the switch and using an Ohm meter or continuity tester. If there is continuity between the switch connector prong and the threaded end of the sensor then the switch has failed.

    • Condition 2 - If the coolant temperature is below 60º C AND the engine speed is greater than 300 RPM AND the oil pressure switch is open.
      This warning is designed to indicate that extremely low or no pressure exists while the engine is running. A healthy engine should have oil pressures well above the switch trigger limit of 1.4 to 1.6 bar (20.3-23.2 psi) Note: 70-100 PSI are common during startup. A disconnected switch, defective switch or broken wire to the Instrument Cluster would trigger this type of warning.

    • Condition 3 - If the coolant temperature is above 60º C AND the engine speed is greater than 1500 RPM AND the switch is open for more than ½ Second
      This warning condition is designed to alert the driver that the pressure is too low during normal operating conditions. At 1500 RPM a healthy engine should be creating at least 30 PSI at 1500 RPM. If this specific condition occurs more than 3 times during continuous operation when warning will continue to stay active at any RPM



    I
    t's important to note that if you receive the warning light while driving and your engine speed is over 1500 rpm (Condition 3) you should consider this a serious situation. It is highly recommended that you stop the car safely and immediately and not drive it. Based on the repair history of this model, and Volkswagen/Audi Recalls for engine sludge problems, there is a strong likelihood that your engine indeed does have low oil pressure and this is not simply a broken wire or failing switch. While many people like myself have no idea what the warning means the first time they see it and do continue to drive you are risking causing more serious and permanent damage by doing so.


    One more important warning. It is common for the
    pressure warning to come on between 1500-1800 rem where the pressure is operating close to the warning threshold. However, if you have the warning light while driving at highway speeds 2500 rpm or above then this means you engine is only pressure is dropping below switch threshold 17-23 psi when you should have about 40+. THIS IS A VERY SERIOUS CONDITION which if you continue to drive there is a very strong likelihood that you WILL cause permanent bearing damage.


    Before we move on the the next section it is very important to note that the Oil Pressure Warning is NOT the problem it is the symptom of an underlying engine problem.
    Last edited by El Negro 2007; 31-07-2015, 12:20.

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    • #3
      Re: Presion de aceite VW 1.8T ( no bora jaja)

      Cuanto llega a 90... esta en 25 de presion aprox...

      Comment


      • #4
        Re: Presion de aceite VW 1.8T ( no bora jaja)

        me surgio la duda xq en caliente oscila entre 65 y casi 80, cargando presion de turbo, me parece un poco elevada por eso preguntaba

        Comment


        • #5
          Re: Presion de aceite VW 1.8T ( no bora jaja)

          Si acelerando llega a 75 80psi...

          Comment


          • #6
            Re: Presion de aceite VW 1.8T ( no bora jaja)

            Originally posted by bezum View Post
            me surgio la duda xq en caliente oscila entre 65 y casi 80, cargando presion de turbo, me parece un poco elevada por eso preguntaba
            a 6000 rpms tendrias que tener mas de 100 PSI en los cojinetes, alrededor de 60 PSI a la salida de la bomba y +/- 35 PSI en la galeriao canal o vena principal de aceite del block

            Comment


            • #7
              Re: Presion de aceite VW 1.8T ( no bora jaja)

              El auto lo saque hace un par de dias del taller y en la calle no le tiro tantas vueltas, pero por lo que me dicen estoy en los rangos normales,lo acelero un poco en 2da o 3ra , esta cargando 20 psi de presion de turbo, igual este finde le hago cambio de aceite y filtro y revisar los metales y bajarle un poco la presion de turbo,es un demonio cuando carga jaja, gracias por las respuestas

              Comment


              • #8
                Re: Presion de aceite VW 1.8T ( no bora jaja)

                Originally posted by bezum View Post
                El auto lo saque hace un par de dias del taller y en la calle no le tiro tantas vueltas, pero por lo que me dicen estoy en los rangos normales,lo acelero un poco en 2da o 3ra , esta cargando 20 psi de presion de turbo, igual este finde le hago cambio de aceite y filtro y revisar los metales y bajarle un poco la presion de turbo,es un demonio cuando carga jaja, gracias por las respuestas
                mmmmmmm....cagon !


                video o ban.....
                jajaja

                saludos !!!

                Comment


                • #9
                  Re: Presion de aceite VW 1.8T ( no bora jaja)

                  Originally posted by El Negro 2007 View Post
                  mmmmmmm....cagon !


                  video o ban.....
                  jajaja

                  saludos !!!

                  jajaja, vos te cagaras de risa, pero la primera vez que me lo dio, cargaba 10 psi y me temblaba todo, el finde pasado fui, me lo acomodo un poco y me dijo aca tenes un auto con turbo y cuando me subi dije ta igual, ahora cuando cargo presion se patino TODO, la verdad se hizo esperar pero valio la pena; no es por hacerme el samaritano pero acelerar en la calle con mi cajon de manzanas es un suicidio, ahora voy acomodar el tren delantero y ponerle unos discos mas grandes, ni bien pueda subo un videito, saludos

                  Comment


                  • #10
                    Re: Presion de aceite VW 1.8T ( no bora jaja)

                    BEZUMM felicitaciones loco ante todo te vengo siguiente el proyecto, que lindo que lopuedas empezar a disfrutar.
                    de donde medis presion de aceite??
                    cuanto te mide en frio regulando? a cuanto regula tu auto?
                    cuanto te mide en caliente regulando y acelerando?

                    en frio regulando deberia andar masomenos igual que acelerando en caliente

                    Comment


                    • #11
                      Re: Presion de aceite VW 1.8T ( no bora jaja)

                      Originally posted by g1.6t View Post
                      BEZUMM felicitaciones loco ante todo te vengo siguiente el proyecto, que lindo que lopuedas empezar a disfrutar.
                      de donde medis presion de aceite??
                      cuanto te mide en frio regulando? a cuanto regula tu auto?
                      cuanto te mide en caliente regulando y acelerando?

                      en frio regulando deberia andar masomenos igual que acelerando en caliente
                      1) No se de donde toma exactamente, pero CREO que toma bien de abajo
                      2) En frio regulando(1.200 - 1300 rpm) exactamente me mataste
                      3) En caliente regulando 15-20 y acelerando piola llega a 80-90

                      Comment


                      • #12
                        Re: Presion de aceite VW 1.8T ( no bora jaja)

                        Originally posted by bezum View Post
                        1) No se de donde toma exactamente, pero CREO que toma bien de abajo
                        2) En frio regulando(1.200 - 1300 rpm) exactamente me mataste
                        3) En caliente regulando 15-20 y acelerando piola llega a 80-90
                        en frio regulando deberia andar en esos 80 o 90,
                        yo creo que esta bien la presion, nose si regulando a 1300 en caliente 15 me parece un toque bajo pero nada apenas, 20 esta joya

                        Comment


                        • #13
                          Re: Presion de aceite VW 1.8T ( no bora jaja)

                          Originally posted by g1.6t View Post
                          en frio regulando deberia andar en esos 80 o 90,
                          yo creo que esta bien la presion, nose si regulando a 1300 en caliente 15 me parece un toque bajo pero nada apenas, 20 esta joya
                          Si igualmente mañana seguro se lo llevo a Tito y cambie el aceite y filtro y revise metales y baje un poco la presion de turbo

                          Comment


                          • #14
                            Re: Presion de aceite VW 1.8T ( no bora jaja)

                            Originally posted by bezum View Post
                            jajaja, vos te cagaras de risa, pero la primera vez que me lo dio, cargaba 10 psi y me temblaba todo, el finde pasado fui, me lo acomodo un poco y me dijo aca tenes un auto con turbo y cuando me subi dije ta igual, ahora cuando cargo presion se patino TODO, la verdad se hizo esperar pero valio la pena; no es por hacerme el samaritano pero acelerar en la calle con mi cajon de manzanas es un suicidio, ahora voy acomodar el tren delantero y ponerle unos discos mas grandes, ni bien pueda subo un videito, saludos
                            Si acomodas el tren delantero seguro mejora la frenada, ahora un disco mas grande, con misma mordaza y misma pastilla no te hace frenar mas.

                            Comment


                            • #15
                              Re: Presion de aceite VW 1.8T ( no bora jaja)

                              Originally posted by tano02 View Post
                              Si acomodas el tren delantero seguro mejora la frenada, ahora un disco mas grande, con misma mordaza y misma pastilla no te hace frenar mas.
                              me exprese mal voy a cambiar todo el conjunto, discos,mordazas y pastillas saludos

                              Comment

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