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Thread: Engine oil kin my poor old Ferrari 308

  1. #1
    Senior Member nicktruman's Avatar
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    Engine oil kin my poor old Ferrari 308

    Hi Guys
    Slightly off topic, but I am hoping someone might be able to help me.
    My 3l v8 Ferrari 308 has 75k miles on it and a very strong engine.

    When I bought it 10 years ago it had great oil pressure hot and cold, I then changed the oil and ever since I have great oil pressure until it warms up, where the pressure can drop to just about 0 on the gauge (not really very accurate Ferrari electronics) at idle and at about 100 deg c water and oil tem.

    I am now running Ferrari oil 10 w 40 and that makes no difference either, it takes 10 quarts of oil!!

    at 2000 rpm the pressure quickly picks up to about half it is at cold and stays tere through the rev range to 8000 or 9000 rpm

    is there much difference between 10w 40 and say 15w 50/20w 50? would that make that much difference? The engine makes no noises (apart from a very loud broom broom noise when you hit the gas).
    Regards
    Nick

    Twin turbo V8 Zonda inspired thingy

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    Maybe the oil is getting too thin when warm?
    Maybe your oil pump is failing?
    Maybe the gauge is simply wrong?
    We need to rule out the possibilities


    Have you run a straight 30 weight and checked the pressure ?
    I wouldn't leave the 30 weight in permanently , but it will be fine for only a few hundred miles for testing

    It would help rule out whether its the oil, your oil pump , or oil gauge that's the culprit .

    Alternative you can splice in another good gauge to verify if your reading is correct

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    Your oil pump only moves oil around.
    You weight (10W30) of oil represents the thickness (flow rate) of oil at different temps.
    Your engine bearings (cams mostly) make oil pressure.
    Your oil gauges display the results.

    Use an oil pressure gauge to verify low pressure and OEM gauge accuracy. if pressures below manufacturers specs replace bearings (usual cam bearings).


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    Senior Member nicktruman's Avatar
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    The oil pressure gauge is electric and runs off the bottom of the filter which is between the V in front of the carbs just behind the flywheel. I have tried to fit a mechanical gauge but cant find any where or way to do it. I an believe the gauge isn't perfect, but we the engine cold eve at idle I have great pressure, so the 10w bit of oil seems good, however its the 40 it I am thinking is too thin for a hot engine. water tem is about 100 deg c and oil 120 ish.
    I know with Ferraris pressure is not as important as flow, I have no issues with flow I think. is there anything I can add to the oil to thicken it up to test this theory? I am due for an oil change now.The AGIP ENI i-Sint 10W-40 oil Ferrari recommend (and am using) costs fortune!!
    Regards
    Nick

    Twin turbo V8 Zonda inspired thingy

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    No, that's backwards. The higher the weight the thicker the oil. If you really wanted "thicker oil" then you'd go to 20w50. I don't know if you can get "lucus" brand oil additive, but I like and use it. (Not in everything but when appropriate).

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    Senior Member murcie-me's Avatar
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    Hmmm. This "broom broom" noise concerns me, can you elaborate more on this?
    The "w" does not stand for the "weight" of the oil. its a number assigned based on the performance of that oil at low temperatures. The lower the "w" number, the better the oil performs in cold start or cold condition enviorments. The "w" actually stands for "winter".
    Last edited by murcie-me; 04-05-2014 at 06:55 PM.
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    Senior Member murcie-me's Avatar
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    So all these advertised "high pressure" oil pumps available are just a waste of money, and dont really produce a higher oil pressure? So i guess fuel injectors make the fuel pressure, not the fuel pump?
    Last edited by murcie-me; 04-05-2014 at 07:02 PM.
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    Yes you are correct the "w" stands for winter or cold viscosity. Just most of us old farts call it "weight" as the higher the number the more viscus. And the Lucus I suggested has a viscosity improver.

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    Quote Originally Posted by murcie-me View Post
    So all these advertised "high pressure" oil pumps available are just a waste of money, and dont really produce a higher oil pressure? So i guess fuel injectors make the fuel pressure, not the fuel pump?
    Do not confuse oil systems with fuel systems as fuel delivery systems need to have bearings or some form of restriction built into them to produce the pressure. Most manufacturers add the pressure restrictions as part of the fuel pump design for safety reasons. Restricting fuel lines, tanks, filters etc. not really practical or safe. Basic engine oil systems by their nature have restrictions built in as they use cam, crank bearings, etc. so the oil pumps usually just provide needed flow rates. Some newer engines and diesels need more pressure than the bearing restrictions can provide so "high pressure" pumps come in to play. All pump pressure does is “fill in the hole” and refresh the oil in the annular space faster than the leak expels it. This is why low-speed engines have relatively large journals, with only modest pump size and pressure. Low pressure indicates that leakage from the bearings is higher than the pump’s delivery rate. Test oil pump flow rate for pump failure then test oil pressure for engine bearing wear.
    Bearing in mind (bad pun) there are exceptions to everything.


  10. #10
    Senior Member murcie-me's Avatar
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    I think you are looking at this wrong, pressure is a byproduct of restrictions in a line, but those restrictions in no way "make" the pressure. Although there would be no pressure in a line without restrictions, without the pump pumping the oil through the restrictions there would be no flow/force to produce pressure in the line. The same holds true for fuel systems (hence the reason fuel pumps are available in different output pressures), water hoses, and balloon blowing lol.
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