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Thread: Hot Running Engine

  1. #1
    Member Pokette's Avatar
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    Default Hot Running Engine

    My engine consistently runs hot - 220 and above. I have only the oil temperature gauge.
    It takes about 15 minutes - regardless of ambient temperature to reach 220, and then continues up to 220 and sometimes 230 if i'm not careful.

    I have the new oil cooler plenum installed. I did not notice an oil temperature drop.

    I have run with aeroshell, Phillips and now exon extreme - none made a difference.

    I was wondering what your temperatures are?
    Is there anyone out there with a dynon or more instrumentation that has an idea about cylinder head temps or exhaust temps?

    Anyone with some ideas (on how to cool it down)?

    I know I can mess around with baffeling (more air through the cylinders to cool the oil, and more air to the cooler), new oil cooler (have to adjust the plenum myself), and air egress (lip extension etc.). I do not have any instrumentation other than oil temp so i'm hoping someone out there have more information or CubCrafters has tested some of these ideas.

    Did you all know that TCM recommends an "ideal" temperature range of 175-195?
    They also quote a max temperature of 225? Our handbook and POH says 240. I was wondering if anyone knows why the discrepancy?

    Also can anyone tell me what consistently running hot will do to my engine? Excessive wear? Shorter TBO? - what are the effects?

    Thanks for any help.
    Diana
    Last edited by Pokette; 07-15-2010 at 01:46 PM.

  2. #2
    Senior Member randylervold's Avatar
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    Default Re: Hot Running Engine

    Diana,

    We have tried a 9-row oil cooler (standard is a 7-row) here on our S2 demo and it lowered the oil temps about 15°. You seem to have chronically high oil temps, more so than any other plane, so we'd be happy to let you try this larger cooler. My understanding is that Stan has already made that offer to you. Contact Ethen Hughes if you're interested and let's get this fixed.
    Randy Lervold

  3. #3
    Member Pokette's Avatar
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    Default Re: Hot Running Engine

    I had heard about the 9 row vs. the 7 row and it had not been tested. Today is the first I heard about 10-20 degree drop and you say 15. Do you have any data for that that you can share? That still leaves me at 200-210 if I see the same drop. Also I was going to have to make my own plenum and connecting hardware and Stan or Ethen mentioned something about a kit. That would make my life easier. I would also like to know about any planned modification to the egress or something similar to the Carbon Cub with those ducts on the front to force more air in.

    If I do have an unusually hot engine I would like to know what others are running. Just Curious.

  4. #4
    Senior Member randylervold's Avatar
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    Default Re: Hot Running Engine

    We have no planned mods other than the larger oil cooler/plenum kit. Our 2nd generation plenum can be easily modified by bending the side plates out to fit the wider cooler, then using some aluminum tape to cover the gaps, but we're working on one that is a simple bolt-on to put in the kit.

    Under most conditions the S2 cools just fine, but there have been a couple of owners operating in hot or high conditions with oil temps unfomfortably high, but of course only in high ambient temp conditions. We believe this oil cooler/plenum kit will adequately address the issue.
    Randy Lervold

  5. #5
    Member Pokette's Avatar
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    Smile Re: Hot Running Engine

    So I guess I have a hot engine...
    15 degrees still puts me over 200.
    I see my engine go to 220 within 15 minutes even on days where the ambient is 85, and yes it is usually humid here - not like your high desert

    What else can be done?
    Thanks.

  6. #6
    Senior Member couleeone's Avatar
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    Default Re: Hot Running Engine

    Before I installed the performance exhaust I ran below 200, now that the weather has finally warmed up post installation I am running up to 220, sometimes a little less.

    Stan indicated that the plenum will be available for a complete larger oil cooler package in about two weeks. I am waiting till then and will be installing it as soon as it is available especially since I will be headed for AZ in a couple of months.

  7. #7
    Member Pokette's Avatar
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    Default Re: Hot Running Engine

    ah... so i am not the only one, and Geo doesn't live in hot hot hot st. louis - 95 today with a heat index of 106 - whew....

  8. #8
    Senior Member Pilawt's Avatar
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    Default Re: Hot Running Engine

    Diana, have you checked the gauge accuracy? My original gauge had to be replaced when it was found to be reading about sixty degrees LOW. Early on I thought I had a cool-running engine; it was hard to get it out of the lower yellow range, but it turned out to be the bad gauge.
    Jeff Jacobs
    Vancouver WA / KVUO
    C-172N-180


  9. #9
    Member Pokette's Avatar
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    Default Re: Hot Running Engine

    Yup, on my second gauge as well.

  10. #10
    Member Pokette's Avatar
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    Default Re: Hot Running Engine

    So Geo, after the 4 into none?!?!
    That reduced your egress area and probably effected delta p
    I think the only good fix for me is to increase my egress area and change the lip hopefully giving me a greater delta p and a 30 degree change.
    The only problem with that is the cost of a new lower cowling if I goof this one up.

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