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Thread: 2.6 engine help/oversize Pistons

  1. #1
    Join Date
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    2.6 engine help/oversize Pistons

    G'day folks, I have pulled the head off my 2.6 engine which comes out of a 5 door 2a station wagon. Engine is a runner but blew blue smoke and all cylinders had compressions around 90psi. I squirted some over down the cylinders and this resulted in a increase of pressure. I thought this warranted further investigation.

    When I pulled the head off there is no shoulder at the top of the stroke and I can still see cross hatching from I presume which would be from a recent rebuild. I was wondering if anyone could help my identify what oversize cylinders are in my engine? Or what else could be causing this oil burning and low cylinder pressure. I think they are 30thou oversize maybe but I thought the rings only came in 20thou, 40thou......?? I will post a picture below. Thanks for the help.

    Cheers, Hamish

    image.jpgimage.jpg

  2. #2
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    check the piston slop,

    it may not have been ringed correctly,

    it may have dicey valve settings or hinky valve stems and seals.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

    Fozzy, 2.25D SIII Ex DCA Ute
    TDI D1(parting/ed)
    Tdi autoManual d1 (Kept it for the girlfriend)
    Archaeopteryx 1990 6x6 dual cab(This things staying)


    If you've benefited from one or more of my posts please remember, your taxes paid for my skill sets, I'm just trying to make sure you get your monies worth.
    If you think you're in front on the deal, pay it forwards.

  3. #3
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    I had problems where the motor had been 'dusted' and the rings were badly worn.

    FFR Refurb

    If there is no ridge and you can see cross hatching you'd think the rings were OK.
    As Dave mentioned, it could be valve guides or the seals in the inlet guides.

    Pistons used to come in +.010, .020, .030, .040 & .060" but it depended on the aftermarket as to what was available for what motor. Yours appear to be +.030"

    I hand scraped the wear ridge, honed & fitted new rings in mine. Also fitted new guide seals and re-seated the valves. Doesn't smoke now, but to be fair, it hasn't been used in anger.


    Colin
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  4. #4
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    Maybe someone lined up the ring gaps like in my diesel engine i recently rebuilt. Not lined up now of course...lol
    Cheers, Rod


    BETSY
    1967 Series 2a. 109 4 cyl petrol, Fairey o/drive, Athol Hedges roof.
    Currently undergoing rebuild.
    Will have-- soft top, 4 wheel disc brakes, salisbury rear diff, military colour, 12 pin nato socket, dual pintle hitch....

    1975 Series 3. 109 6cyl 186, 5 speed Nissan cabstar gearbox, mechanical winch, roo bar, kings awning, 50" light bar, roof rack, twin 6"light bars, kings awning tent.

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  5. #5
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    Thanks everyone for the help. I will investigate further and see what the go is. Pulling out the pistons should narrow things down a bit. Hopefully there won't have to be full rebuild like I was expecting maybe just a tidy up and make sure everything is reasonable order.

    Cheers, Hamish

  6. #6
    Join Date
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    May have been over teated at some stage & rings have lost there tention & as some one else said check the ring gaps are not inline . They need to be 180 deg to each other & top away from the exhaust valve.

  7. #7
    UncleHo's Avatar
    UncleHo is offline Part of the Heart and Soul of AULRO Gold Subscriber
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    Exclamation

    Hi
    Yes,over heating can cause the rings to loose tension,which results in poor starting,smoking,lack of power,if that is the problem a new set of rings is the only way out

    Cheers
    68 2a GS 6028D 172-484
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  8. #8
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    Hi all,

    To avoid letting things get out of hand I am tackling one section of the engine at a time, starting with the head. I am thinking of taking off the rockers so I can take the head into town and get someone to look at the valves and see if the head needs milling flat.

    However I have run into trouble with getting the rocker shaft out. In the parts book it is split into two sections apparently and according to the manual you need special tool No. 262749. It looks as one half will come FWD and the second half will come AFT. I have removed the 3 locating screws on the which secure the rocker shaft.

    Just wondering If anyone has had success with extracting the rocker shafts without the special tool. If so, how did you do it?

    IMG_2753.jpgIMG_2755.jpg

    Thanks, Hamish

  9. #9
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    Quote Originally Posted by morty View Post
    Hi all,

    To avoid letting things get out of hand I am tackling one section of the engine at a time, starting with the head. I am thinking of taking off the rockers so I can take the head into town and get someone to look at the valves and see if the head needs milling flat.

    However I have run into trouble with getting the rocker shaft out. In the parts book it is split into two sections apparently and according to the manual you need special tool No. 262749. It looks as one half will come FWD and the second half will come AFT. I have removed the 3 locating screws on the which secure the rocker shaft.

    Just wondering If anyone has had success with extracting the rocker shafts without the special tool. If so, how did you do it? hi i have a good 6 engine here if you need ji

    IMG_2753.jpgIMG_2755.jpg

    Thanks, Hamish
    ihave a motor here jim
    Russell Rovers
    Series I Parts Specialists
    russellrovers AT gmail.com
    Phone 0428732001

  10. #10
    Join Date
    Aug 2006
    Location
    Melbourn(ish)
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    25,095
    rubber hose, a small insert tube and nuts bolts and washers.

    slot the threaded end of the bolt (you may want to do this AFTER you assemble the tool

    get a nice long bolt, slide a washer in, slide some insert tube on and then feed the rubber hose section over the top of that.

    add another washer and a nut.

    slide it in bolt head first, tighten the nut onto the bolt assembly using the slot you cut as a screwdriver slot for a flat head.

    As the nut winds onto the bolt the rubber expands inside the rocker tube and will get a grip, out she pots.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

    Fozzy, 2.25D SIII Ex DCA Ute
    TDI D1(parting/ed)
    Tdi autoManual d1 (Kept it for the girlfriend)
    Archaeopteryx 1990 6x6 dual cab(This things staying)


    If you've benefited from one or more of my posts please remember, your taxes paid for my skill sets, I'm just trying to make sure you get your monies worth.
    If you think you're in front on the deal, pay it forwards.

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