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Identify this engine component

Discussion in 'Technical Discussion' started by Capt Fred, Oct 8, 2018.

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  1. Capt Fred, Oct 8, 2018
    #1
    Capt Fred

    Capt Fred Senior Member

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    I have J&T 671, 485 HP engines in my 1987 Ocean 44. Help me identify this engine component. The canister is located on the inboard side, it has 2 hoses, the larger one goes to the crankcase, pictured and the smaller one goes to the blower bypass valves. My guess is that it is a breather for the crankcase and the bypass valves.

    While I'm at it, how do you know the by-pass valves open and what boost pressure do they start to open?

    All help is greatly appreciated,

    Attached Files:

    Last edited: Oct 8, 2018
  2. Flybull, Oct 9, 2018
    #2
    Flybull

    Flybull New Member

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    I believe you're correct on the breather identification... I think the newer models had the breather moved to the valve covers...

    As for the pressures... can't help you on that. :)
  3. Capt Fred, Oct 9, 2018
    #3
    Capt Fred

    Capt Fred Senior Member

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    Thanks for your help
  4. Oscarvan, Oct 10, 2018
    #4
    Oscarvan

    Oscarvan Senior Member

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    My guess.....I think it's an oil catch can to capture oil out of the crank case vent air, and reduce carbon buildup on the intake valves..... Just installed one on my Ford van. Unscrew it and find it full of oil.... I empty mine every 1500 miles. I would check this every 100 hours and see how much you catch.
  5. Capt Ralph, Oct 11, 2018
    #5
    Capt Ralph

    Capt Ralph Senior Member

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    I remember an old post on this. Please do a YF search. 671 breather. Someone came up with a replacement element.
  6. Capt Fred, Oct 12, 2018
    #6
    Capt Fred

    Capt Fred Senior Member

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    I'm convinced it is a breather, I took it apart, small amount of puckey oil inside and and a wire mesh filter in the can. Also has a petcock on the bottom for draining. Thanks for the help.
  7. Capt Ralph, Oct 12, 2018
    #7
    Capt Ralph

    Capt Ralph Senior Member

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    That is also a fancy check valve on it. It will flow away from the air box at very low air pressure.
    Designed to let oil drain from the air box at idle. When pressure builds up, that check valve will close keeping pressure from building up in the crank case. Also keeping any pressure for top end boost.
    The screen is to capture sludge and and grime that gets blown into the air box and not drain back into the sump with the oil.

    The return tap on the blower may just be an easy access point for return oil.

    Later versions of this looked like an old Fram 1 quart fuel filter.

    I'm sure most of this info was on an old post already but I could not find it.
  8. Capt Fred, Oct 13, 2018
    #8
    Capt Fred

    Capt Fred Senior Member

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    Capt Ralph, thanks for the explanation of the check valve.
  9. Beau, Oct 13, 2018
    #9
    Beau

    Beau Senior Member

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    Capt

    Is this a version of the old "puke" can?
  10. Capt Ralph, Oct 13, 2018
    #10
    Capt Ralph

    Capt Ralph Senior Member

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    Yes