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4G54 Motor swaps

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  • 4G54 Motor swaps

    Hi all, new member, just bought an '87 ND or NE LWB for a song with a suspected shot big end (2.6 petrol). Big question is, has anyone succesfully used a motor out of a sigma/magna? What fits what? I know the Magna's run a different head, the water pump is on the flywheel end, but is the block the same? Are the 2.6 sigma's a drop in? Any help is greatly appreciated as a motor from a pajero will be hard/expensive to get, whereas i can get a running sigma or magna fairly easily and cheaply.
    '91 NH 2.5TD gq springs, side steps, 120L Diesel tank, Airflow Snorkel, Alloy Bull Bar.

  • #2
    There used to be so much info about this sort of job on the old site, however as most guys have moved onto newer machines it seems the older material wasn't a priority for shifting accross to the new site. Hopefully your query has some of the other members feeling all nostalgic and want to share some of their experiences.

    I bought my old NC with #4 conrod out the side of the block. A friend had some old 2.6 sigma engines lying around his shed in bits.

    First steps:
    I used the 'tin' that is sandwiched between the block and the transmission's bell housing to see if his blocks would mate up to my paj's gearbox. He had 3 blocks. The tin matched up to two of them. These were the 'wider' blocks and were originally from sigmas with manual trannies. His other block was from an automatic sigma and was too 'narrow', so was ignored.

    I checked to see if my Paj's head would fit on the 'wide' blocks. It would have very happily fit on either of them. I then checked to make sure the Paj's sump would fit on either of the 'wide' blocks. Again, it would have fit either of them.

    I then chose the block with the best bores and the crank with the best journals, gave the cyls a hone, lapped the valves, checked all tolerances, fitted new bearings / rings / gaskets, bought one new Paj (flat top) piston (as the Paj's other 3 piston sets were fine) and had it pressed onto one of the sigma conrods my mate had lying around and whapped it all back together and it fit perfectly back into the Paj's engine bay and looks just like a bought one.

    So,,,, my NC then had, a sigma block, Paj pistons, one sigma conrod (ZACTLY DA SAME), sigma crankshaft (wide and narrow block crankshafts = same), Paj head and flywheel and manifolds, and a mixture of the best balance shafts / timing gear etc etc.

    Note that the sigmas (up until the GN that is) had a head with smaller valves / combustion chamber, but combined this with dished pistons.... all sorts of opinions about pros and cons of either set up... you'd want to know what you're doing before mixing them up I expect. If you MUST use a pre-GN sigma head, you'll also need to use the intake manifold from that head, as the paj intake manifold won't bolt up to it.

    So yeah, wait until pick-a-part has a bare engine special (usually about $50), and go get a manual 2.6 sigma engine, spend another $200 on oils, solvents, gaskets, rings, bearings and misc goop, then after a weekend or so you'll be back on the road.

    Good luck


    • #3
      From (another) long time Early paj owner:

      "I?ve heard a number of rumours regarding unreliable Sigma 2.6?s and block cracking Magna 2.6?s. You may wonder - was this bad blood transferred to the genes of their cousin - the Pajero 2.6? Definitely not! My Paj clocked up 284,000 K's before the motor required it's first rebuild. Yes - the three motors are similar in design and share engine parts, however - dissimilar enough to make a real difference and I understand that the Pajero has an advanced head design which outflows the others considerably. I get the feeling that Mitsubishi put a lot more quality and thought into the building of their early Pajeros - as they prepared to enter a tough 4WD market dominated by their rivals, Toyota'.

      When the above owner rebuilt his paj. motor he
      replace the standard cam with a mild cam and new springs, include a set of extractors and a free-flowing sports system and had the balance shaft removed and the motor balanced. For even more go-go, he fitted a Webber carbie [not holly] and said it would leave a V6 3000 for dead, which is only 400c bigger than a standard 2.6 / 4 anyway.

      In the mid-80's the paj. won 4 wheel drive of the year several times. I still have a long wheel based high roof 86' in good nick and due to it's off road ability, simplicity and heavier build than later models, I'm not keen to change.

      If you have picked up a good body etc. I'd reco the motor if it's a genuine paj motor and keep away from sigma motors [unless desperate].
      Last edited by akabilk; 05-12-07, 01:36 PM.


      • #4
        Thanks for the help guys, I have gotten on to a sigma I will throw in while I look at options to get the original motor rebuilt. Its done almost 300k so will probably need a bit of work unless I can get on to a cheap second handy. The body is in bloody good nick though so is worth spending the time\money on and the driveline looks pretty good so far. Interesting link too. cheers
        '91 NH 2.5TD gq springs, side steps, 120L Diesel tank, Airflow Snorkel, Alloy Bull Bar.


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