Just Commodores Forum Community

It takes just a moment to join our fantastic community

Register

Not this again, which engine oil?

Discussion in 'VT - VX Holden Commodore (1997 - 2002)' started by NeddyBear, Feb 14, 2015.

  1. shadetreemechanic

    shadetreemechanic Member

    Messages:
    228
    Likes Received:
    1
    Trophy Points:
    18
    Joined:
    Jan 2, 2011
    Location:
    perth
    Members Ride:
    VR v6
    Its true that a thinner oil will reach the lifters better but its mainly important for cold starts. Even a 60 weight is just fine when warmed up.

    The main reason they spec 30 weight in the US is due to CAFE regulations and its used since most engines will go the entire warrany period without issues. Your link mentions HTHS which is measured at 150 degC. Have a look at the huge difference in HTHS between a 30 and 50 weight.

    The owners manual was recommending an ILSAC GF2 rated oil which is an eco spec (ILSAC GF spec is labelled "resource conserving"). Otherwise use 15w40 or 20w50 so the initial 30 weight recommendation is purely for fuel economy reasons.
     
    Last edited: Feb 15, 2015
  2. Jxfwsf

    Jxfwsf Well-Known Member

    Messages:
    4,852
    Likes Received:
    91
    Trophy Points:
    48
    Joined:
    Feb 20, 2011
    Location:
    Aus
    Members Ride:
    commodore
    If a lifter additive doesn't rectify a noise then it's nothing the viscosity will fix (even the bottles say they don't magically fix mechanical failure) regardless of how quick/slow it gets there.
    I always thought the general rule of thumb was pushrod engine >20WXX, ohc <15WXX, then you take in the year the engine was manufactured and what bearing/machining tolerances were used at that time to suit.

    buick/ecotech v6 vs alloytec... machining, metals, tolerances, technology and the machinery used to make the engine depend on what it should be running, sure a lighter weight oil will get to the lifters quicker but will it provide the lubrication requirements of the lower bearings?
     
  3. BlackoutSteve

    BlackoutSteve Member

    Messages:
    409
    Likes Received:
    3
    Trophy Points:
    18
    Joined:
    Jan 5, 2014
    Location:
    Melbourne
    Members Ride:
    WH Caprice LS1
    The 30 weight recommendation has been around since the 60's and perhaps earlier. Long before CAFE standards were introduced in 1975.

    It would be interesting to see what the HTHS is at a lower temp such as 100°C as 150°C is a temp your oil will never see and the last thing you'd be worried about if it did.
    Anyway, this link shows the 30 to have a number of 2.9 verses 3.7 for the 50 (+28%). Oil Viscosity Explained
    "High-temperature high-shear-rate (HTHS) viscosity is an indicator of an engine oil's resistance to flow in the narrow confines between fast moving parts in fully warmed up engines."
    I'm assuming the lower the number the better. I can't see how more resistance to flow could ever be preferred.

    30 weight "purely for fuel economy reasons"? I doubt that. :)
    Like I said, 30 weight was still the standard during the Big Three's horsepower wars of the mid-late 60's/early 70's when no one gave a crap about fuel economy.

    The bearing clearances have pretty much always been 0.001" per inch of diameter. Nothing much has changed.
    I think people assume the use of heavier oils in older engines because they assume that they have been worn to larger bearing clearances. Open up a 400K engine and take a measurement. I did and the 0.0003" (3 tenths of one thou) thick top layer of tin was still on every bearing shell.
    Even guys with newly rebuilt old engine are still stuck in this old-engine-thinking and continue to use 25W50 that they didn't need to use in the first place. If they read their manual, even of their older cars, they would see 30 weight. My 69 Chevy's owner's manual lists the 30 weight part number.
    A thicker oil will help reduce oil consumption, but that's due to worn rings and seals.

    A thicker oil won't help keep bearings apart. It's the hydrodymanic oil wedge that does that. Not the viscosity.
     
    Last edited: Feb 15, 2015
  4. Jxfwsf

    Jxfwsf Well-Known Member

    Messages:
    4,852
    Likes Received:
    91
    Trophy Points:
    48
    Joined:
    Feb 20, 2011
    Location:
    Aus
    Members Ride:
    commodore
    These engines could benefit with a zinc additive but that'll screw sensors (and hurt captain planet), they run huge tolerances with tri metal bearings in a cast iron block, hell they'd last millions of km's if we still had leaded fuel.
    At the end of the day it's old technology designed to run on older (and getting to be obsolete) oils.
     
  5. VR38

    VR38 Well-Known Member

    Messages:
    3,076
    Likes Received:
    27
    Trophy Points:
    48
    Joined:
    Dec 23, 2008
    Members Ride:
    VB SL/E

    Not quite opposite, a "thicker oil" will remain insitu longer that a thin oil, retaining some protection at start up but yes, fully agree, a thin oil, albeit at reduced pressure, will produce a quicker oil film on cold start up.
    It really comes down to which is more usable (to the bearing or lifter) flow v's pressure?

    FWIW in freezing conditions on a cold start (well any ambient temperature below the operating point of the thermostat for that matter) the thermostat CAN NOT maintain almost exactly the same temp all year around until the engine has had a chance to warm up.
     
  6. VR38

    VR38 Well-Known Member

    Messages:
    3,076
    Likes Received:
    27
    Trophy Points:
    48
    Joined:
    Dec 23, 2008
    Members Ride:
    VB SL/E
    All manufactures and oil companies agree, majority of wear happens at start up.
     
  7. BlackoutSteve

    BlackoutSteve Member

    Messages:
    409
    Likes Received:
    3
    Trophy Points:
    18
    Joined:
    Jan 5, 2014
    Location:
    Melbourne
    Members Ride:
    WH Caprice LS1
    The thicker oil sticking on parts for longer idea is point mute. :)
    When an engine cools down, ALL oils become way too thick and will adhere to parts in the same way anyway.
    Get an engine that's been sitting in a wrecking yard for 20+ years. Remove the oil pan and pull a main or rod cap. You might be surprised that there will still be plenty of oil in the bearings, Just like oil (or water) sandwiched vertically between 2 pieces of glass, -it's not going anywhere.

    When it comes to start up, correct, of course it's impossible for a thermostat to maintain engine temperature, which is why I'm scratching my head at your suggestion of very thick 15-20 Winter grades.
    Don't assume that a winter grade is actually has a viscosity of 15-20 when it's cold.
    At ~20°C, even a 0W30 has an actual viscosity of about 40. What do you reckon it's viscosity might be during an overnight low of 0°C?

    Next time you do an oil change, be careful, but try to do it when the engine is at it's normal operating temperature. Notice how "thin" the oil is and how well it flows out of the oil pan.
    Then when refilling, compare the viscosity of your cold 15-20WXX that you assume flows well enough, and notice the massive difference. When refilling. I bet you have to keep stopping to prevent the funnel from overflowing because it's so thick and moves so damn slow.
    So, there is absolutely now way it can be pumped around the engine anywhere as easily and do it's job as well like when it's up to temp. Even a 0WXX is still much thicker.

    There is no motor oil available anywhere that has a viscosity low enough for cold starts, or one that doesn't require light throttle/low load warming up to the "correct" viscosity.
     
  8. shadetreemechanic

    shadetreemechanic Member

    Messages:
    228
    Likes Received:
    1
    Trophy Points:
    18
    Joined:
    Jan 2, 2011
    Location:
    perth
    Members Ride:
    VR v6
    LOL, I think you're talking about a monograde 30 weight back in the 60s!!! Holden (and GM in the states) introduced a requirement for ILSAC GF2 10w30 around about when the VT came out.
    If you don't believe the fact that the oil is for economy look up ILSAC....dunno what else I can say to that....
    And the HTHS test is specifically carried out at 150 degC. Why would they test something that as you say, "your oil will never see"???

    This I agree with. I never said anyone should use 25w50 or even 10w60.
    With current synthetics the difference between all the 5w40, 5w30 and 0w40, 0w30 isn't all that much really so they're almost interchangeable. Some of these can be pretty stout as long as the HTHS is high enough. For an old Buick/Ecotec they're a bit on the thin side though and a 5w50 or 10w50 might be a lot more suitable.
     
    Last edited: Feb 17, 2015
  9. BlackoutSteve

    BlackoutSteve Member

    Messages:
    409
    Likes Received:
    3
    Trophy Points:
    18
    Joined:
    Jan 5, 2014
    Location:
    Melbourne
    Members Ride:
    WH Caprice LS1
    Straight 30? C'mon..
    GM part number 9985183 for the 1969 factory Assembly Manual. Would you like a photograph of the page?
    https://global.ihs.com/doc_detail.cfm?document_name=9985183&item_s_key=00394604

    I'm also not saying the 10W30 isn't better for economy. I'm sure it is, but it's not chosen "purely for economy" like you suggest.

    Do you honestly think your oil is reaching 150°C/302°F on a regular basis while your coolant is ~100°C/212°F ?
    If it ever did, it would be rarely and for an instant.
     
  10. shadetreemechanic

    shadetreemechanic Member

    Messages:
    228
    Likes Received:
    1
    Trophy Points:
    18
    Joined:
    Jan 2, 2011
    Location:
    perth
    Members Ride:
    VR v6
    Well we all know how much GM loves to supersede part nos. Is your manual actually from 1969?? And a modern (even ILSAC spec) 10w30 is much more preferable than a straight 30 obviously.

    The thing is that certain engine parts do reach temps as high as that. In fact even bulk sump oil can reach temperatures as high as 130 or so since that's mentioned in the Nissan GT-R owners manual (they say dump the oil asap if it ever reaches 130 LOL)

    edit: I did notice your link mentions 10w30 (with Zinc) so that oil has boosted ZDDP so that's a bit of a giveaway....
     
  11. Skydrol

    Skydrol Well-Known Member

    Messages:
    339
    Likes Received:
    2,101
    Trophy Points:
    93
    Joined:
    Dec 4, 2013
    Location:
    USA
    Members Ride:
    Pontiac G8 GT
    Realy, says that? That is interesting. Yes I do believe the crankcase oil can reach higher temps since it travles around the engine, not the same passages as the coolant but other areas with no way to go out (exchange heat). The Crankcase Oil Pan is not a good Heat Dissipator, might help transfering some heat but does not have a good way to do a good heat transfer. The only way I see the oil to cool properly is with an Oil Cooler or have a Crankcase Dry Sump and use the remote reservoir as a cooler. The reason for a bigger oil pan is too give the oil time to cool a bit and to keep the engine with a constant flow (oil moves around during corenering, de/acceleration, inclines, etc...). Coolant temps depending on the engine (most US Cars) does not go above the boling point (100C/212F), they run about 88C/190F for normal operating temp, and about 99C/210F for the fans to kick in. If you reach 100C/212F easy, is your warning of some bad is about to happen or your system is deficient.

    Keep in mind, the temp reading comes from the coollant's hottest spot (cooling system wise, around the engine coolant out hose). The crankcase (the PCV system is not a good heat extractor), perhaps is much hotter, only way to tell how hot is to install an Engine Oil Temp Sensor.
     
  12. BlackoutSteve

    BlackoutSteve Member

    Messages:
    409
    Likes Received:
    3
    Trophy Points:
    18
    Joined:
    Jan 5, 2014
    Location:
    Melbourne
    Members Ride:
    WH Caprice LS1
    Of course it's a superseded part number.. The whole manual is full of superseded part numbers that no longer work.. It's from 1969.
    This is a superseded number from the 1967 manual.
    https://global.ihs.com/doc_detail.cfm?document_name=9985002&item_s_key=00394780

    If you were familiar with GM numbers, you'd see straight away that these are numbers from that era..
    If the part gets changed, improved, revised, the number also is changed.
    Those numbers won't do anything for you are a GM dealer today except get you the modern version with the modern number.

    With zinc.. Do you think adding zinc to oil is a new thing?
    Several of the engines those oils were used in were solid lifter with moderate spring pressures. Of course they knew about using zinc.
     
  13. BOOST666

    BOOST666 Classic not plastic

    Messages:
    257
    Likes Received:
    1
    Trophy Points:
    0
    Joined:
    Apr 18, 2012
    Location:
    NSW Central Coast
    Members Ride:
    '79 VB SL/E 253, VY SS II
    Venta del Baron is a nice oil
     
  14. XUV

    XUV Member

    Messages:
    527
    Likes Received:
    6
    Trophy Points:
    18
    Joined:
    Feb 22, 2009
    Members Ride:
    HSV XUV
    Just buy what ever syn oil they have on special on said day and you won't go far wrong.
     
  15. VR38

    VR38 Well-Known Member

    Messages:
    3,076
    Likes Received:
    27
    Trophy Points:
    48
    Joined:
    Dec 23, 2008
    Members Ride:
    VB SL/E
    Sorry you asked yet? LOL.

    FWIW if your car is standard then refer to the owners hand book for correct oil selection and change intervals.
    Holden has been spending billions of dollars for more years than most of us have even owned one.
    If you have mechanical issues then it is quite clear changing oil is not going to fix them, neither is a choice in weight on the thin or thick side (within scope Holdens recommendations) going to cause you mechanical problems.
    I would suggest getting three quotes from competent mechanics and starting a new thread if a mechanical problem exists.
     
  16. shadetreemechanic

    shadetreemechanic Member

    Messages:
    228
    Likes Received:
    1
    Trophy Points:
    18
    Joined:
    Jan 2, 2011
    Location:
    perth
    Members Ride:
    VR v6
    No that was a rushed comment edit. What i meant to say is that the addition of ZDDP is a giveaway that its an old formulation and needs the ZDDP in order to protect adequately. Most modern 30 weight oils have low zinc levels especially ILSAC grades as that is a requirement of the "resource conserving" certification.
    Any oil can be loaded up with ZDDP but then it will kill cats...of course its no issue in a car built before anyone worried about emissions.
     
    Last edited: Feb 17, 2015
  17. NeddyBear

    NeddyBear Veteran Mountain Biker

    Messages:
    1,456
    Likes Received:
    168
    Trophy Points:
    63
    Joined:
    May 5, 2011
    Location:
    Queensland
    Members Ride:
    2004 Subaru Outback 2.5 & 2002 VX II Acclaim
    I don't have a good understanding of the V6 engine so last weekend we bought a used 2002 V6 engine for $100 and what I'm doing is pulling it apart to see how the engine comes apart and to see whats inside.
     
  18. Skydrol

    Skydrol Well-Known Member

    Messages:
    339
    Likes Received:
    2,101
    Trophy Points:
    93
    Joined:
    Dec 4, 2013
    Location:
    USA
    Members Ride:
    Pontiac G8 GT
    Well... there is no need to spend $100 to see the engine inside. They are plenty diagrams in the web to look and to be honest, is just like a V8 minus 2 cylinders ;)
     
  19. VR38

    VR38 Well-Known Member

    Messages:
    3,076
    Likes Received:
    27
    Trophy Points:
    48
    Joined:
    Dec 23, 2008
    Members Ride:
    VB SL/E

    Well done, what a fantastic idea.
    My first job when I left school was as a engine builder.
    What an eye opener being hands on.
    Do yourself a favour and get a holden hand book and some measuring tools so you can see what is worn and where then you can deduce why.
     
  20. BlackoutSteve

    BlackoutSteve Member

    Messages:
    409
    Likes Received:
    3
    Trophy Points:
    18
    Joined:
    Jan 5, 2014
    Location:
    Melbourne
    Members Ride:
    WH Caprice LS1
    Yep, great idea.. This is the best way to learn.
    I thoroughly recommend text books, BUT all the text books in the world won't put a spanner in your hand and give one bit of hands-on experience.

    Keep parts organized and labelled and note their orientation as the engine comes apart. This way you'll be able to see patterns if you're interested in how an engine normally and perhaps abnormally wears.

    Depending on your intent, you can buy cheap micrometer sets and telescoping bore measuring tools that can really help you understand clearances etc.
    Used Mitutoyo stuff is great value.
     
    Last edited: Feb 25, 2015

Share This Page