Dry Sump question... Oil flow from catch tank to sump.

Discussion in '308/328' started by Andy 308GTB, Apr 17, 2017.

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  1. Andy 308GTB

    Andy 308GTB Formula 3
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    After 5+ months of labour, I am about to take my car off the axle stands and start it up. I've had the sump cover off, so the final job is to top the engine oil up.

    The car is sitting level, the catch tank is filled to the maximum level per the dipstick but there is no oil in the sump. I think the oil should simply flow, under gravity into the engine? But it isn't. (I don't think it is pumped from the catch tank to the engine)

    The oil pump must be between the sump and the catch tank (because it scavenges the oil from the sump and returns it to the catch tank). So if there is no oil in the sump the oil pump has nothing to pump?

    I've done numerous oil changes prior to this and simply filled up the catch tank to the correct level, fired the car up and a little while later checked the dipstick and topped up if necessary. I may be overthinking this and what I really need is a lesson in basic dry sump engines.
     
  2. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Yes, but it has to "flow" thru the very small clearances in the low-pressure scavenging pump as you noted, so it's not a rapid flow and can be zero depending on the clearances, surface tension of the oil, etc.. I wouldn't worry about it too much as there isn't any oil on the valve train either (other than what's residual) so similar situation there. The more important thing is to have oil present at the inlet to the high-pressure pump, and with oil present in the oil tank = you've got that.
     
  3. Andy 308GTB

    Andy 308GTB Formula 3
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    Cheers Steve.

    So on that basis, if I start the car up, let it run for a few seconds, I should see the level of oil in the catch tank drop?
     
  4. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Yes, the oil level should drop down as the lines, cooler, sump get refilled and things get rewetted. You could also disable the ignition and just crank it over a few times to drop the level and add more if you are super-concerned, but as long as you've got pressure shown on the OP gauge all is OK (running the engine for a few minutes, even low a few quarts, is no problem as long as the oil pressure is good).
     
  5. Andy 308GTB

    Andy 308GTB Formula 3
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    Perfect.
    I will pull the king leads from the coils and turn it over a few times to check that the sump is being filled.
     
  6. Martin308GTB

    Martin308GTB F1 Rookie
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    #6 Martin308GTB, Apr 17, 2017
    Last edited by a moderator: Sep 7, 2017
    Hi Andy,

    glad to hear that your car will be back on the roads soon.
    Steve already said all you have to know regarding your concerns. But for understanding of the dry-sump system allow me to add, that you actually have two pumps.
    The first one indeed pumps the oil from the tank and under pressure through the engine. Basically this is the pump the wet-sump cars have too. After lubrication of all, this oil fills the sump.
    The second, chain driven one, is the scavenge pump, which just pumps the oil from the sump back to the tank via the oil cooler.
    The drawing in the owner's manual shows the circuit nicely.

    Best Regards
    Martin
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  8. 4right

    4right Formula 3
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    This is an interesting topic for me as well as I have the exact opposite issue. My car has been in storage for a period of time. I recently checked the oil level in the oil tank and it was completely empty. My assumption is that over time, all of the oil drained into the sump.
     
  9. Martin308GTB

    Martin308GTB F1 Rookie
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    #8 Martin308GTB, Apr 17, 2017
    Last edited: Apr 17, 2017
    Probably. But also probable, that your oil level was already low prior to putting the car into storage.
    When I put my car into winter storage with the oil level on 'max.' it's a few mms below 'min.' after three to four months. But never completely empty.

    Best Regards
    Martin
     
  10. Andy 308GTB

    Andy 308GTB Formula 3
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    The first pump, i.e. between the tank and the engine. Is this mechanical or electrical?
    When I first was looking at buying a 308, I was told to let the pumps run for a few seconds before starting the engine, to let the pump distribute the oil.
     
  11. Albert-LP

    Albert-LP F1 Rookie
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    there isn't any electrical oil pump. Oil goes from the tank to the main oil pump in the engine by gravity. There is another oil pump in the sump that pushes the oil to the oil tank, buyt it just cleans the oil sump and fills the oil tank, it doesn't lubricate anything

    ciao
     
  12. Patrick Dixon

    Patrick Dixon Formula Junior

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    The electrical pump is the fuel pump. Let it run for a few seconds before starting to build up fuel pressure.
     
  13. Andy 308GTB

    Andy 308GTB Formula 3
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    Are you sure?
    If you look at the diagram posted earlier, where the blue line ends and the red line starts - this looks like a pump to me. I'm at work now, so I can't check but there is definitely something that could be an electrical pump there.
    In any case, the catch tank outlet is at about the same level as the sump, so it can't use gravity.

    Just thinking aloud :D
     
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  15. Martin308GTB

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    #13 Martin308GTB, Apr 18, 2017
    Last edited by a moderator: Sep 7, 2017
    Andy,

    attached a picture of a not so common view, which we rarely see.

    this is the pump, but it's mechanical and integrated in the front cover together with the cambelt drive.
    The pump gears are hidden behind that smaller drive gear-wheel in the picture below.

    The other, lower pump is the scavenge pump. Also driven by the main assembly via a chain.

    Picture shows F40 parts but it's basically the same on our cars.

    Best Regards
    Martin
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  16. PSk

    PSk F1 World Champ

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    Not really, the oil pump will be sucking oil into it.

    By ensuring oil is already there, by gravity, means that there is no oil pressure issue on start up, due to sucking air.
    Pete
     
  17. Albert-LP

    Albert-LP F1 Rookie
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    the suction punp ("pompa di recupero", that is doubled, with two suctions points and two couple of gears) takes the oil from the sump and sends it to the oil radiator and then the oil pours into the oil tank.

    By gravity, the oil from the tank reaches the main oil pump and then to the oil filter and to the engine

    Ferrari 308 GTB (1980) - Lubrification System (308 GTB): Page 015 | Order Online Eurospares

    Ferrari 308 GTB (1980) - Oil Filter and Pumps (308 GTB): Page 016 | Order Online Eurospares

    No electricity. No oil pumps in the tank. Suction pump in the sump (spiltted in two) - oil radiator - oil tank - gravity- main oil pump - oil filter - engine - gravity - sump

    ciao
     
  18. Andy 308GTB

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    Thanks All!
    My knowledge of the dry sump system is now considerably better than it was yesterday afternoon. And it makes good sense.

    As an aside, I got the car all ready to turn over last night. Checked everything over for the 10th time. Battery fully charged, all fluids in place, all nuts torqued up etc.
    Turned the key. Click, Click, Click, Click...

    Dead battery. Showing 12.55 volts but not enough juice to kick the starter motor into action. I then ordered a new battery online and have now found that the vendor is the biggest cowboy out there. I am already paving the way to reclaim the money back via PayPal because there is absolutely no way they will be able to fulfil my order.
    I will order another one today from a reputable company for delivery tomorrow.
     
  19. Martin308GTB

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    Hi Andy,
    regarding battery supply; Is there no 'offline-source' near your home? I'm quite 'living in the woods', but with things like these (batteries and other non-Ferrari-specific stuff) I still prefer 'offline-supply', which means just driving 10mls. in my case.

    Best Regards
    Martin
     
  20. Andy 308GTB

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    There are outlets within a few miles of my home (Halfords, EuroCarParts etc.) but I'm in the City of London during the week. I could wait until the weekend but I'm keen to get this finished.
    EuroCarParts and others will deliver next day if I order before 4pm so that's what I'm going to do.

    FYI this is the website that I ordered from originally:
    Cheap Car Batteries, Leisure Car Batteries, Specialist Car Batteries, Motorcycle Batteries Online UK Shop
    I really wasn't thinking when I clicked to complete the purchase. Just for fun compare the website to the premises:
    https://www.google.co.uk/maps/uv?hl=en&pb=!1s0x487b723291a1640d:0x8d36ae38b754ee73!2m19!2m2!1i80!2i80!3m1!2i20!16m13!1b1!2m2!1m1!1e1!2m2!1m1!1e3!2m2!1m1!1e5!2m2!1m1!1e4!3m1!7e115!4s/maps/place/just%2Bcar%2Bbatteries/@53.782356,-2.6659138,3a,75y,161.13h,90t/data%3D*213m4*211e1*213m2*211s6UiytqZglN9M7h_Xk2NH7g*212e0*214m2*213m1*211s0x0:0x8d36ae38b754ee73!5sjust+car+batteries+-+Google+Search&imagekey=!1e2!2s6UiytqZglN9M7h_Xk2NH7g&sa=X&ved=0ahUKEwjuu9qK7K3TAhVHKVAKHWXgBHUQpx8ImQEwCg

    I was expecting a vast warehouse :D
     
  21. Martin308GTB

    Martin308GTB F1 Rookie
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    Hi Andy,
    hmmm.. the outer appearance of the premises is not always a mandatory sign for good or bad service. At least I have experiences with proper 'glass-palaces' and poor service.
    The google ratings sound not good, except one, but are not enough to form an opinion.
    We have a high-tech CNC-parts manufacturer here with the most modern machinery, fast and reliable delivery, but the premises are looking like a rattrap on the outside.

    In reverse I know a lot 'all kippers and curtains'. (as far as I know, this is exclusively British English. right? But anyway, you are British :))

    Best Regards
    Martin
     
  22. Andy 308GTB

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    #20 Andy 308GTB, Apr 18, 2017
    Last edited: Apr 18, 2017
    'All fur coat and no knickers' is another similar expression...
    But I agree with you, lots of my favourite local services are based in little more than caves but they don't have websites that make them look like multi-national corporations!

    The reviews of JustCarBatteries in general are dire. I've called their website phone number and the number on the front of the shop multiple times this morning and not got a response. The amount they wanted for the battery was not realistic, I suspect the website is not updated properly. I paid using PayPal so I'm not concerned about the cash. I'll let you know how this goes...


    Update London 12:49...
    I got through to JCB on the phone and they say they have the battery in stock and it should be dispatched today.
    I may hold off ordering a replacement until the weekend and see how this goes.
     
  23. Albert-LP

    Albert-LP F1 Rookie
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    The oil tank purpose is to separate air from oil and have a column of oil over the main oil pump inlet. All the system is conceived to avoid any air in the oil (no foams, no emulsions). The oil level in the tank is higher than the main pump inlet height, so it can "fall by gravity". Of course the oil pumps are gear pumps so they have some suction properties, but all the purpose is to avoid that the main oil pumps has to raise the oil, keeping the inlet pressure over the atmospheric pressure: The oil is already over it and completely air free due to the air separator (the oil tank, where air separates from oil due to the oil flow very low speed). This is why dry sump exists: It avoids that the main oil pump aspires oil with air inside.

    Ciao
     
  24. pshoejberg

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    Hi all. Sorry to bump this thread slightly. I am working on a friends Euro 1978 GTB308 dry sump and have a couple of questions. Firstly I can see that there is a threaded hole in the bottom of the oil tank indicating a sensor of some form to be installed; Is this correct, and given case which type of sensor should be installed? Secondly, are there anyone that knows where I can source a electrical diagram for this car?

    Best regards

    Peter
     
  25. Andy 308GTB

    Andy 308GTB Formula 3
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    Yes, a sensor does screw into the bottom of the oil catch tank. I won't guess what it does, I'll let someone else answer that.

    Wiring diagrams, you can buy big ones here apparently...
    Wiring Diagrams 308 365 400i 512
     
  26. mike996

    mike996 F1 Rookie

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    It is common for dry sump oil systems to eventually drain the oil tank into the sump if the engine sits for an extended period.

    Also, as noted, all the oil pumps are mechanical. An electrically driven engine oil pump would be suicidal. ;)

    FWIW.. ON THE STREET - a dry sump system has no advantage and several disadvantages over a wet sump engine. It's only advantages, and the reason it exists, is that under severe G force, - cornering or acceleration - a poorly designed wetsump system can allow the pickup to be uncovered briefly. The dry S overcomes that problem and also allows for a lower center of gravity for the car by allowing the engine to sit lower in the body/frame IF the car is designed to take advantage of that ability.

    But otherwise it's a problematic system for normal operation. It's more complicated, heavier, takes more engine power to run, and exhibits the "drain down" that has been mentioned.

    Proper design of wetsump systems/oil pans eliminates the issue with G force oil starvation although the advantage of the lower center of gravity for a competition car still exists for a dry sump.
     
  27. Steve Magnusson

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