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Thread: EJ257 PH2 2.0 heads new build

  1. #1
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    EJ257 PH2 2.0 heads new build

    A while ago I fitted my 2.5 engine, contacted Bob Rawl, who gasped at the spec knowing it was on the 'chocolate pistons' and I promptly removed it and replaced the original 2.0 engine.

    The 2.5 is sitting on the engine stand looking unloved, albeit with a new belt kit, uprated idlers and new 11mm oil pump.

    So, I've been advise by Alyn to closed deck it, which seems a good idea. What I need advice on is which pistons and rods to go for?

    Do I really need a Nitrided crank or will the standard crank do?

    Obviously I'll fit new ACL bearings or equivalent.

    Oh and I've never built and engine before -it can't be that hard surely??? ;-)

  2. #2
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    All depends what power you want, I've not been a fan of the 2.5 for obvious reasons, it's severely compromised cylinder wall thickness compared to the 2.0 unit.

    Crank wise the cost is the same for both versions, so you may as well go for nitrided, although both are steel billet items and pretty bullet proof, the bearings you use matter most.

    Engine building is pretty straight forward on these, main thing is that the machining is done properly with the appropriate clearances used depending on piston material and power levels. Biggest issue with the 2.5 is the head gaskets failing and not trying to run too much cylinder pressure for the spec.

  3. #3
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    Power? Up to 400bhp. Probably 380/380. If I want more then it'll probably be a 2.1 or 2.35.

    I was going to use the crank that came with the engine. When the blocks are being closed deck inserts fitted, I'll get the bores checked and ask for pistons to match. I'm not too sure on clearances though and I think went for large clearance on your build due to Mahle piston expansion characteristics?

    Any bearing recommendations or at least, ones to avoid?

  4. #4
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    400BHP is not a lot, get the crank checked for journal size, if it needs grinding it's better just to throw it away for the hassle and cost.
    I use Mahle motorsport big end and ACL main bearings.

    At that sort of power level you don't need the high expansion 2618 pistons that require the bigger clearances (the 2618 is noisier, especially when cold), just match the clearance to the piston spec you use.

    As its a used block and you intend to insert it, i would just go for the next step up oversize set of pistons and bore to the spec it needs.
    You could use the later stock spec rods too.

    All depends on how much you want to go belt and braces with it and how much you want to spend. My build could handle a lot more power than it has, i built a lot of headroom into it, it's done 68K miles since I refreshed it in 2013. Make sure you use new head bolts or buy some head studs and then torque to spec. I went the 14mm/12mm route so had the block machined to 14mm just so it could handle the higher cylinder pressures of 9.3:1 compression and 2.0BAR+ boost (i only run 1.8BAR on the current turbo).

  5. #5
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    It's a 'free' spare engine, where I'm happy to go sub 400bhp on it. I want more torque and a degree of reliability, on a modest budget.

    I still drive my car to and from track days and have been doing so for 20 years. I like the idea of 'big' power but not at the expense of reliability and also the extra cost. If I trailered the car then it would be a different matter.

    I expect to use new pistons, rods, bearings, bolts and studs. I'm not sure I need larger than stock size fasteners but I would consider uprated ARP for instance (Extreme etc). I would prefer to use my existing crank if checked ok.

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