• Welcome to River Dave's Place

Oil cooler thermostat

Discussion in 'RD's Lounge' started by rrrr, Jun 28, 2019.

  1. rrrr

    rrrr Well-Known Member

    Messages:
    7,732
    Likes Received:
    10,948
    Joined:
    Dec 19, 2007
    I'm curious to know if it's common to run an oil cooler thermostat on big HP boat racing engines. They're used on some racing applications I've worked on, but I don't recall seeing any comments about them on RDP.

    The closed loop engine cooling systems obviously have thermostats, but how well does that produce an acceptable oil temperature? With the reduced clearances and lower viscosity oils that are now common, I'm thinking precise oil temperature regulation is more important.

    Running sustained oil temps above 220° F allows accumulated combustion water products to boil off, which in turn prevents the production of hydrochloric and sulphuric acids. Actually, this really isn't a big problem, because the detergent in engine oils is suffciently alkaline to neutralize any acid formation, and the oil is changed long before the additives lose effectiveness.

    But I like the idea of positive oil temperature control, instead of just assuming it's OK because engine coolant temps are regulated. Using a thermostat on drive oil coolers also sounds like a good idea. Getting the oil up to an acceptable operating temperature before putting the hammer down should result in less wear.

    This is the oil cooler thermostat I've used...

    [​IMG]

    http://www.improvedracing.com/oil-t...uct_search&utm_source=googleproductsearchusen
     
    Last edited: Jun 28, 2019
    HydroSkreamin likes this.
  2. Racey

    Racey Maxwell Smart-Ass

    Messages:
    14,509
    Likes Received:
    17,601
    Joined:
    Sep 18, 2007
    Yes, they work excellently.
     
    HydroSkreamin likes this.
  3. LargeOrangeFont

    LargeOrangeFont Steers With Throttle

    Messages:
    17,985
    Likes Received:
    20,927
    Joined:
    Sep 4, 2015

    I run a Mocal oil thermostat in my car. It is what Improved Racing based their thermostat design off of.

    I don’t have an answer for you regarding oil thermostats in boats, but I’d assume yes. That is likely why people have trouble with car engines in boats.. a car engine is not set up to run 120F thick oil under a heavy load.
     
    rrrr likes this.
  4. Don Johnson

    Don Johnson Don Johnson

    Messages:
    1,476
    Likes Received:
    1,501
    Joined:
    Mar 1, 2008
    It really is dependent on the motor builder preferences and how they set up the clearances.

    I will tell you that Teague (TCM) does not use themostats and runs the water and oil as cool as possible. On my TCM 1,250's the oil and water run approx 120 degrees in the river and 130 degrees in summer water on Havasu. I am assuming that the temps are being taken after the oil coolers. When I run my boat up to the Hoover dam my temps dont even register on the gauges
     
    LargeOrangeFont likes this.
  5. Racey

    Racey Maxwell Smart-Ass

    Messages:
    14,509
    Likes Received:
    17,601
    Joined:
    Sep 18, 2007
    Yep, many problems can arise from the oil not getting warm enough to evaporate the moisture/condensation from the crankcase.

    Of all the motors i've been around and serviced in marine applications, the ones with cool water systems, and warm oil systems work the best.
     
  6. rrrr

    rrrr Well-Known Member

    Messages:
    7,732
    Likes Received:
    10,948
    Joined:
    Dec 19, 2007
    Before practice sessions and going on the grid, we started the engine and warmed the oil in our 3.5L Honda Indy V-8s to 100° C.

    Which is, of course, 212° F, the boiling point of water.
     
    LargeOrangeFont and Racey like this.
  7. LargeOrangeFont

    LargeOrangeFont Steers With Throttle

    Messages:
    17,985
    Likes Received:
    20,927
    Joined:
    Sep 4, 2015
    If the engine is set up with that temp expectation in mind I’d assume it is all good generally speaking.

    What is the oil change interval on those?
     
  8. Don Johnson

    Don Johnson Don Johnson

    Messages:
    1,476
    Likes Received:
    1,501
    Joined:
    Mar 1, 2008
    I think TCM knows what they are doing.

    Oil change required every 25 hours, big blowers and boost pushes a lot of fuel past the rings. That said, i do my oil changes myself and the oil is always crystal clear and free of any moisture contamination and the valve covers are always clean/clear. Same holds true for all the GT Performance engines I had, no oil thermostat and perfectly clear oil
     
  9. LargeOrangeFont

    LargeOrangeFont Steers With Throttle

    Messages:
    17,985
    Likes Received:
    20,927
    Joined:
    Sep 4, 2015

    Yea I’d agree they know what they are doing.

    Here in the desert I’d doubt you’d see much moisture contamination.
     
  10. Don Johnson

    Don Johnson Don Johnson

    Messages:
    1,476
    Likes Received:
    1,501
    Joined:
    Mar 1, 2008
    My boat was set up to go to Canada with seat and floor heaters. TCM knew that was to be used in near freezing water and still no thermostats. Just saying that there are many big builders that like the motors to run at very low temps, there are benefits to it, like keeping piston tops and valve springs cooler. Reduced potential for detonation, reduced expansion rates etc etc
     
  11. LargeOrangeFont

    LargeOrangeFont Steers With Throttle

    Messages:
    17,985
    Likes Received:
    20,927
    Joined:
    Sep 4, 2015
    Certainly.

    I know why it is done, you just can’t do that with any old engine out of the crate, for one of the reasons you mentioned... thermal expansion. You’ll kill the pistons in no time if the clearances are off when the engine runs that cool.

    Your engines make 1250 HP, so it’s not like you care if you leave a little power on the table pushing around cool oil in the name of extra safety and longevity. :)

    How much oil does each of your engines hold?

    It seems that some boats don’t use thermostats, or coolers, but run a 15 quart pan and just maintain oil temp by sheer volume of oil.

    Interesting to see the different use cases.
     
  12. ramos45

    ramos45 Well-Known Member

    Messages:
    310
    Likes Received:
    305
    Joined:
    Jun 18, 2015
    I run the Merc HP500 oil filter mount/thermo combo that opens at 212. I don't run a water thermostat. In the summer here on Mead it takes about 4 miles cruising at 3500 rpms before oil temp is up to 180 and at that point i'm free to push the sticks to INFINITY AND BEYOND. I have blowers without chillers so I chose to not run a water thermostat.
     
  13. Don Johnson

    Don Johnson Don Johnson

    Messages:
    1,476
    Likes Received:
    1,501
    Joined:
    Mar 1, 2008
    Mine hold 15 qts with the large HP6 type filter

    Agreed, crate motors would not do well. But rrrr started this as a big HP discussion
     
    LargeOrangeFont likes this.
  14. LargeOrangeFont

    LargeOrangeFont Steers With Throttle

    Messages:
    17,985
    Likes Received:
    20,927
    Joined:
    Sep 4, 2015
    Sorry for the questions. What weight oil do they recommend?
     
  15. Don Johnson

    Don Johnson Don Johnson

    Messages:
    1,476
    Likes Received:
    1,501
    Joined:
    Mar 1, 2008
    straight 50 Kendal or 20/50 Amsoil Dominator Racing which is what i choose to run.
     
    LargeOrangeFont likes this.
  16. LargeOrangeFont

    LargeOrangeFont Steers With Throttle

    Messages:
    17,985
    Likes Received:
    20,927
    Joined:
    Sep 4, 2015
    Additional question -

    Anyone running an Accusump or other oil accumulator for cold starts?
     
  17. Don Johnson

    Don Johnson Don Johnson

    Messages:
    1,476
    Likes Received:
    1,501
    Joined:
    Mar 1, 2008
    Nope, I am told by both TCM and GT that they are pretty much a waste of money. and not worth the added plumbing and another thing to leak or fail.

    And by the looks of my bearings at last tear down at TCM they are right. I could have reused the bearings in both motors.....
     
    LargeOrangeFont likes this.
  18. LargeOrangeFont

    LargeOrangeFont Steers With Throttle

    Messages:
    17,985
    Likes Received:
    20,927
    Joined:
    Sep 4, 2015
    So Teague runs the oil “cold”.

    Do all big HP marine engine do the same? Do the Merc Racing Twin Turbo motors run “cold” oil?

    I have no idea, but my wild guess would be no because of the overhead valve train and turbos.
     
  19. LargeOrangeFont

    LargeOrangeFont Steers With Throttle

    Messages:
    17,985
    Likes Received:
    20,927
    Joined:
    Sep 4, 2015
    Yea.. your molasses oil isn’t running off anything in there :)
     
  20. Don Johnson

    Don Johnson Don Johnson

    Messages:
    1,476
    Likes Received:
    1,501
    Joined:
    Mar 1, 2008
    I have no idea what the temp of the oil is in the pan. That said, TCM runs 2 massive plate style oil coolers in each engine on my deals

    I believe that the Merc 1350's are closed cooling so they run them at temperature. That said, 100 hour teardown intervals..... MY TCM's are 300 hour teardowns intervals
     
  21. LargeOrangeFont

    LargeOrangeFont Steers With Throttle

    Messages:
    17,985
    Likes Received:
    20,927
    Joined:
    Sep 4, 2015
    Yes good point. I’m sure the Mercs are closed cooling as well, forgot about that fact, and that would mean they are indeed running at some temp.
     
  22. rrrr

    rrrr Well-Known Member

    Messages:
    7,732
    Likes Received:
    10,948
    Joined:
    Dec 19, 2007
    I guess those builders have a good handle on the different coefficients of expansion for aluminum and steel, and set up critical clearances accordingly.
     
    LargeOrangeFont likes this.
  23. AZLineman

    AZLineman Well-Known Member

    Messages:
    503
    Likes Received:
    54
    Joined:
    Oct 29, 2008
    I use a Mo-Cal aircraft oil thermostat on my Schiada
     
    rrrr likes this.

Share This Page