Page 2 of 4 FirstFirst 1234 LastLast
Results 16 to 30 of 47

Thread: 1985 4K-J Recommended Oil?

  1. #16
    Forum Member 1st year Apprentice
    Join Date
    Jan 2017
    Location
    Kuala Lumpur
    Posts
    28

    Default Re: 1985 4K-J Recommended Oil?

    Let me put it this way rebuilder86.
    You have 2 cups of water, one with ice in it, the other very hot, at 80C.
    You leave them on your living room table 200mm away from each other. The one with the ice will eventually melt all the ice and the temperature will raise to...exactly the surrounding temp. Same with the hot water, it will lose heat to the ambient air, and eventually reach equilibrium. After 3 hours at 30C ambient room temp, i betcha both cups will have same temp.
    Now how does this translate to the thermostat ? The thermostat only controls flow of coolant to and through the radiator and back. A 82C thermostat starts opening at 82C, and is fully open at 95C and above. Just because the thermostat opens at 82C does not mean the oil temp or coolant temp will stay at 82C. It depends on the capability of the radiator to radiate/expel heat to ambient air around it. the radiator is never 100% effective in doing its job.
    So if the ambient temp is 10C higher than it previously was, the radiator can only expel excess heat and try to match the ambient temp surrounding it. Hence if the ambient temp is higher, so is the coolant temp. All the radiator can do is try to lower the coolant temp, but it can only lower it based on the radiator's cooling capacity and ambient temp around it. There is no feedback loop to the thermostat because its purely mechanical and based on heat expansion of the pellet. So if coolant temp is already 100C but the thermostat at full open is 95C, it is doing all it can to move the hot coolant to the radiator in order to bring down the coolant temp.
    Also keep in mind since the engine is running, burning fuel, creating heat, and also from the shearing of oil in between the engine bearings, all this keeps adding heat to the oil which transfers to all the metal parts and coolant.
    Then it completely depends on the radiator which as I said before is not 100% efficient , and also takes time to reach equilibrium with the ambient air temp.
    An d as Hiro said, the oil temp is usually much higher than coolant temp, studies have shown a 10C to 20C higher temp than coolant temp.
    Noted about your passion on the topic at hand. No offence taken.

  2. #17
    Forum Member 1st year Apprentice
    Join Date
    Jan 2017
    Location
    Kuala Lumpur
    Posts
    28

    Default Re: 1985 4K-J Recommended Oil?

    As for fuel economy, i ran SAE30 mono grade oil for 10000km, and i found that i lost nearly 50km off per tank on my weekly refill. on the next oil change with 5W-40, I got back that 50km extra per tank.
    The only difference is start up viscosity. SAE 30 has a 40C rating of 98cst. The shell 5W-40 is 74cst at 40C.
    That alone made the fuel economy difference on start up.
    And the higher the oil pressure, the higher the fluid friction and lower the economy. Thats why cars these days use 5W-20 or 0W-20.
    As I said before, if your engine clearances are still tight go for lower viscocity, otherwise go for 20W-50.

  3. #18
    Forum Member 1st year Apprentice
    Join Date
    Sep 2017
    Location
    Western Australia
    Posts
    47

    Default Re: 1985 4K-J Recommended Oil?

    nono, 8 didnt say the oil temp would match the coolant temp
    i said tge thernostat regulates the coolant temp and therefor the engine temp.
    i didnt say tga5 the raduator is 100% efficient
    what i tried to say is the engineers attempt to over-engineer the cooling system so that it will cool in extreme environments, and they leave it up to the thermostat to regulate this for all environments.

    now also, hiro, how does environment change the ability of the heat to be absorbed in to the coolant in a cylinder head operating at 120 degrees??
    i dont understand that concept at all.

    my oint still stands, environment doesnt heat up the engine, only load and bigger explosions or a maxed out thermostat.
    a maxed out thermostat shouldnt exist in a first world country where automotive markets must produce a vehicle fit for purpose, which means it cannot overheat due to climate.
    if it overheats, the cooling system is buggered and this is not the fault of the environment.

  4. #19
    Forum Member 1st year Apprentice
    Join Date
    Sep 2017
    Location
    Western Australia
    Posts
    47

    Default Re: 1985 4K-J Recommended Oil?

    to check my sanity, i have thoroughly googled the topic.
    I can only find sensible argument, that go in my favour. by sensible i mean, things that sound like they have some intellect behind them, ie, no forum armchair experts.
    Saying that, the internet is nto allways correct, so use this as a means of research not gospel.
    http://www.popularmechanics.com/cars...mmer-10283951/
    https://www.yourmechanic.com/article...scosity-matter

    http://dannysengineportal.com/thermo...t-performance/ (Not a single one of the abnormal engine temps are attributed "weather, or environment")

    https://autologicgso.com/what-hot-we...s-to-your-car/ (quote "though some people believe it’s necessary to use a thicker grade of oil for summer, and a thinner oil for winter, this isn’t the case with modern motor oils.)


    in winter, does your temp needle sit in another position than where it does in summer?
    No.
    because the thermostat is doing its job.

  5. #20
    Junior Member Too Much Toyota oldcorollas's Avatar
    Join Date
    Aug 2005
    Location
    sydney
    Posts
    12,496

    Default Re: 1985 4K-J Recommended Oil?

    Quote Originally Posted by rebuilder86 View Post
    but the thernostat regulates the temperature.
    so during your winter, it keeps the engine as hot as it is in summer.
    cooling systems are designed to work efficiently in the harshest environment, so that means they can cool an engine in summer.
    the thermostat means that the engine will operate at exactly the same temp in summer and winter.
    eventually anyway, it just may take some time in winter.
    umm... thermostat regulates the LOWER temp of the engine... not the upper.
    thermostat opens at some temp well below "desirable" running temp, and after that it is the capacity of the radiator (vs air temp + road speed) that regulates the upper temperature...

    and different countries experience different extremes of weather.

    Europe/Japan may have -10 to 0 in winter, then 25-40 in summer...
    20W at -10C is not good older cars may take a lot longer to heat up than more modern design cooling systems (crappier block only recirc), so you have have too thick oil for too long in proper low temps.

    Aus may have 20-45 in summer... that extra 5deg temp (close to half the boiling point of water) does make a big difference if the cooling system is marginal.. as it is in old toyotas...

    but it is the oil temp, not the coolant temp, that is important.
    while coolant may be 105C, oil could be 105.. or 130...
    "I'm a Teaspoon, not a mechanic"
    "There is hardly anything in the world that a man can not make a little worse and sell a little cheaper" - John Ruskin (1819 - 1900)

    AU$TRALIA... come and stay and PAY and PAY!!! The moral high horse of the world!

  6. #21
    Forum Member 1st year Apprentice
    Join Date
    Sep 2017
    Location
    Western Australia
    Posts
    47

    Default Re: 1985 4K-J Recommended Oil?

    where is this information coming from. read this please.

    http://www.stant.com/index.php/engli...rmostats/faqs/

    quote.
    WHAT IS A THERMOSTAT? WHAT PURPOSE DOES IT SERVE?
    The thermostat has two important jobs to perform; to accelerate engine warm-up and to regulate the engine's operating temperature. A quality thermostat ensures excellent fuel economy, reduces engine wear, diminishes emissions and blow-by, improves cold weather drivability, provides adequate heater output, and detours overheating. This is accomplished by blocking the circulation of coolant between the engine and radiator until the engine has reached its predetermined temperature. The thermostat then opens as required in response to changes in coolant temperature to keep the engine's temperature within the desired operating range. return to top

  7. #22
    Forum Member 1st year Apprentice
    Join Date
    Sep 2017
    Location
    Western Australia
    Posts
    47

    Default Re: 1985 4K-J Recommended Oil?

    if i keep on getting told i am incorrect by people who are so far missinformed, then maybe this isnt the forum for me.
    how old are all of you?
    dont they teach mechanical workshop in school? or physics?
    Last edited by rebuilder86; 10-10-2017 at 07:09 PM.

  8. #23
    Toymods Board Member Chief Engine Builder Hiro's Avatar
    Join Date
    Apr 2006
    Location
    NSW
    Posts
    3,078

    Default Re: 1985 4K-J Recommended Oil?

    Quote Originally Posted by rebuilder86 View Post
    if i keep on getting told i am incorrect by people who are so far missinformed, then maybe this isnt the forum for me.
    how old are all of you?
    dont they teach mechanical workshop in school? or physics?
    You're mis-interpreting information. As oldcorollas said above (and the link to the Stant website), the job of the thermostat is to restrict coolant flow through the radiator when the car is cold in order for it to warm up faster. Once the coolant reaches a set temperature the thermostat opens and allows coolant to flow through the radiator to try and keep the temperature level. Once the thermostat is open it has NO ability to stop the engine getting warmer, that job falls entirely to the radiator and fans. Higher ambient temperatures means the radiator is less efficient at bringing coolant temperatures down to the desired inlet range, which creates heat-soak in the cooling system and if unchecked will cause a car to overheat. At the minimum it can easily lead to an engine running significantly warmer during summer than winter. This will also mean the oil will be warmer too (as I mentioned above, the oil does form part of the cooling system, not just lubrication), and unless you have an oil-cooler you are relying on conduction/convection in the sump and galleries to cool the oil.

    Bear in mind too that most OEM temperature gauges are little more than glorified idiot-lights - they have no defined range and no way to tell if they are linear, so a "normal" operating position of the needle could actually satisfy a large range of temperatures. By the time the needle is heading north towards the HOT mark it may already be too late.
    Last edited by Hiro; 11-10-2017 at 10:21 AM.
    AE102 - Charlene the Old Faithful, Reborn
    JZZ30 - Lexi the Spacecruiser, 1JZGTE>>3SGE. 200rwkw, hunting Skylines and n00bs in SS Commodores
    ST162 - Charlie the non-ghey Celica, 3SGE>>4AGE. GOOOOOOOONE
    AE82 - Rosie the Bitsa from Hell, 70.8kw atw. Has been converted into garage space and money at last
    KE55 - Billie the Beast, sadly missed

  9. #24
    Forum Member 1st year Apprentice
    Join Date
    Sep 2017
    Location
    Western Australia
    Posts
    47

    Default Re: 1985 4K-J Recommended Oil?

    nah, no disrespect hiro, but i think you are all missing the point. and you all ought to listen as this is fundamental to underatanding the cooling system.
    the radiator is big enough to cool the car to below operating temp if the thermostat was fully open, tested in the clinate the vehicle is to be sold in.
    the twmp is allowes to go above this by the thermostat. it opens to an equilibrium where the coolant surrounding it is somewhere between the opening temp and fully open temp.
    if the vehicle ever has to continualy operate beyond the capacity of the fully thermostat, something is wrong with the cooling system, not the weather.
    If you cannot comprehend that explanatio then im sorry im just shit at explaining physics. but i 100% assure you thats how it is deaigned and i urge you to do some more research and even experiment yourself until u underatand this.
    key points.
    1. the cooling system must be able to cool the engine to the designed operating temp in the extremes of the environment where the vehicle is sold.
    2. the cooling system must flow and exchange heat at such a rate that the thermostat is always capable of operating within the designed temperature range.
    3. the thermostat should never have to operate constantly in fully open position. if it does, there is a fault, either:
    pump failure, air lock, air bubble, leak, blockage, airflow obstruction, combustion issue or incorrect thermostat.

  10. #25
    Junior Member Backyard Mechanic jondee86's Avatar
    Join Date
    Dec 2008
    Location
    Wellington, NZ
    Posts
    485

    Cool Re: 1985 4K-J Recommended Oil?

    There is a reason that it is called a thermostat... curiously enough, because it is designed to try and keep the coolant temperature constant. It does this by modulating how far it opens according to the coolant circulating past the was filled capsule. The control authority of the thermostat is within the range from fully closed to fully open. In my car the thermostat does a pretty good job of keeping the coolant at a steady 85degC.

    If the coolant temperature continues to rise after the thermostat is fully open, the coolant temperature will then begin to float with the coolant temperature rising until the heat gain into the system reaches equilibrium with the heat rejected to atmosphere. Under these conditions, engine load, vehicle speed and ambient temperature will be the major factors affecting the coolant temperature.

    Under normal circumstances (if functioning correctly) the factory cooling system will have sufficient heat rejection capacity to maintain the coolant temperature within the control authority range of the thermostat. The Owners Manual will provide some warning about the possibility of overheating under unusual conditions. And also some recommendations on what oil grades to use for vehicles operated under various climatic conditions.

    If I need a specific recommendation regarding which oil to use in a particular engine, I ask an oil company

    Cheers... jondee86

    PS: Dang... I didn't see the previous post come in as I was writing. Never mind, it looks as so we are on the same page
    Last edited by jondee86; 11-10-2017 at 11:53 AM.

  11. #26
    Toymods Board Member Chief Engine Builder Hiro's Avatar
    Join Date
    Apr 2006
    Location
    NSW
    Posts
    3,078

    Default Re: 1985 4K-J Recommended Oil?

    Quote Originally Posted by rebuilder86 View Post
    nah, no disrespect hiro, but i think you are all missing the point. and you all ought to listen as this is fundamental to underatanding the cooling system.
    the radiator is big enough to cool the car to below operating temp if the thermostat was fully open, tested in the clinate the vehicle is to be sold in.
    the twmp is allowes to go above this by the thermostat. it opens to an equilibrium where the coolant surrounding it is somewhere between the opening temp and fully open temp.
    if the vehicle ever has to continualy operate beyond the capacity of the fully thermostat, something is wrong with the cooling system, not the weather.
    If you cannot comprehend that explanatio then im sorry im just shit at explaining physics. but i 100% assure you thats how it is deaigned and i urge you to do some more research and even experiment yourself until u underatand this.
    key points.
    I understand where you're coming from, and I know how thermostats and cooling systems are designed. I just think you're placing too much credence on the coolant system being the final say in controlling the temperature of the entire engine in all conditions. As has been mentioned several times by me and others, the oil system absorbs some of the heat generated by the engine however it is not directly regulated by the main cooling system (there are no coolant passages through the crank or in the sump, and a lot of older cars do not have oil coolers) and thus is more susceptible to influence from external factors. An engine that is working harder due to a heavier load (towing, hills, hot days etc) will place a greater load on the oil system regardless of the thermostat keeping the coolant at a tepid 85 degrees. This along with cold starting is why manufacturers specify different viscosity oils for warmer or colder climates, yet they don't usually specify a different thermostat (unless you're way up in the polar or high-alpine regions and need a "winter package")
    AE102 - Charlene the Old Faithful, Reborn
    JZZ30 - Lexi the Spacecruiser, 1JZGTE>>3SGE. 200rwkw, hunting Skylines and n00bs in SS Commodores
    ST162 - Charlie the non-ghey Celica, 3SGE>>4AGE. GOOOOOOOONE
    AE82 - Rosie the Bitsa from Hell, 70.8kw atw. Has been converted into garage space and money at last
    KE55 - Billie the Beast, sadly missed

  12. #27
    Forum Member 1st year Apprentice
    Join Date
    Sep 2017
    Location
    Western Australia
    Posts
    47

    Default Re: 1985 4K-J Recommended Oil?

    yes oil takes the extreme heat out of the bearings, conrods and other lower components, but the outside air temperature does not affect that oil on its own in the crankcase, because the engine operates a multitude times higher temp than anywhere on earth.

    a vehicle with a correctly functioning thermostat, once at operating temp, will run at the same temperature (oil temp) in the middle of the day in a hot desert as it would in the middle of the night during winter.
    Engine load will change that, (oil only) but that is not what we are arguing about here so why bring it up haha.
    you will find no scholarly research articles on the affects of ambient temperature on the crankcase oil because it doeant correlate at all.
    the only time engine oil is affected by climate is at startup.
    never when hot.

  13. #28
    Forum Member 1st year Apprentice
    Join Date
    Sep 2017
    Location
    Western Australia
    Posts
    47

    Default Re: 1985 4K-J Recommended Oil?

    unless u are a ricebox driver and have an external oil cooler... then everything changes.
    otherwise, the biggest heat generator for oil is the cylinder head, and its temp is governed by.......
    u guessed it, coolant tempt

  14. #29
    Toymods Board Member Chief Engine Builder Hiro's Avatar
    Join Date
    Apr 2006
    Location
    NSW
    Posts
    3,078

    Default Re: 1985 4K-J Recommended Oil?

    Quote Originally Posted by rebuilder86 View Post
    yes oil takes the extreme heat out of the bearings, conrods and other lower components, but the outside air temperature does not affect that oil on its own in the crankcase, because the engine operates a multitude times higher temp than anywhere on earth.

    a vehicle with a correctly functioning thermostat, once at operating temp, will run at the same temperature (oil temp) in the middle of the day in a hot desert as it would in the middle of the night during winter.
    Engine load will change that, (oil only) but that is not what we are arguing about here so why bring it up haha.
    you will find no scholarly research articles on the affects of ambient temperature on the crankcase oil because it doeant correlate at all.
    the only time engine oil is affected by climate is at startup.
    never when hot.
    I'm not saying that ambient air temperature directly changes the temperature of the oil sitting in the sump (apart it slowly cooling or warming to match when everything is settled), I'm saying that climate conditions can affect the load the engine is placed under which THEN affects oil temperatures (moreso than coolant temperatures which as you have stated should be kept in check by a proper functioning cooling system). An engine seeing higher loads due to higher air temperatures will have higher oil temperatures, and therefore a higher grade oil may need to be specified in order to give the desired actual viscosity at that temperature. That is what this discussion is all about. You have been hammering on about how you believe that ambient temperatures have no affect on oil viscosity because of the thermostat regulating engine temperature, and myself (and others) have been rebutting that coolant temperature/thermostats are only a part of the story and more things have to be considered when it comes to the oil, hence why manufacturers recommend a range of viscosities depending on conditions.
    Last edited by Hiro; 11-10-2017 at 02:36 PM.
    AE102 - Charlene the Old Faithful, Reborn
    JZZ30 - Lexi the Spacecruiser, 1JZGTE>>3SGE. 200rwkw, hunting Skylines and n00bs in SS Commodores
    ST162 - Charlie the non-ghey Celica, 3SGE>>4AGE. GOOOOOOOONE
    AE82 - Rosie the Bitsa from Hell, 70.8kw atw. Has been converted into garage space and money at last
    KE55 - Billie the Beast, sadly missed

  15. #30
    Forum Member 1st year Apprentice
    Join Date
    Sep 2017
    Location
    Western Australia
    Posts
    47

    Default Re: 1985 4K-J Recommended Oil?

    hiro give me an honest answer here.
    did u just go and add this to ur previous post:
    specifically the part in brackets.
    .............
    You can have a perfectly normal functioning coolant system and oil temperatures can continue to rise past that due to the load on the engine (which will be higher in hotter temperatures because the engine is ingesting hotter air and working harder to produce the same power)

Similar Threads

  1. Recommended oil for W58 box?
    By Niko in forum Tech and Conversions
    Replies: 1
    Last Post: 24-06-2016, 07:22 PM
  2. Recommended Supercharger Oil
    By cush in forum Tech and Conversions
    Replies: 14
    Last Post: 15-03-2008, 03:15 PM
  3. Recommended CCA for a 4AGZE?
    By PooJou in forum Tech and Conversions
    Replies: 3
    Last Post: 18-08-2007, 07:32 AM
  4. Recommended Autoelectricians in Qld
    By Mr Multivalve in forum Tech and Conversions
    Replies: 4
    Last Post: 09-12-2006, 08:31 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •