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Thread: Anatomy of a bulletproof S52?

  1. #1
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    Anatomy of a bulletproof S52?

    Hullo all!

    I think I am going to rebuild the S52 in my E30 track car over the winter.

    More power, while I wouldn't say no to it, is not the primary goal here; what I am trying to do is add reliability.
    I want to know that I can hammer on the car now and forever, and she'll keep coming back for more. She is an HPDE toy, not an all-out racecar, although she has a welded in half cage, gutted interior, etc. She's pretty hardcore, but as I am not racing her, I don't need every last bit of power.

    I understand that using the car in this manner will cause more wear and tear on the motor, and I know that lack of maintenance, 'money-shifting' and time will still cause damage to motor, no matter how you build it. But, what I want to do is build the strongest S52 'endurance' engine that I can.

    So, what areas should I be considering? Eagle rods? Solid lifters? Dual Valve Springs? Forged Pistons? Coated bearings? ARP head studs & crank studs?

    Some history that may be relevant:
    This is a normally aspirated S52, converted to OBD1. Stock cams. M50 intake manifold, OBD2 exhaust manifolds with the secondary O2 injection ports welded up. 413 red label DME running a TRM chip for 91 octane, M50 manifold, standard weight flywheel 21.5# injectors - all the things my car has.

    Metric Mechanic did some minor work on the head a couple of years ago (skimmed it very slightly, added stronger valve retainers, new valve guides & seals, and replaced a couple of valves, as the motor had been left sitting and there was some corrosion/pitting on 2 of them).

    The motor has standard pistons with oversize rings. A hone was done at a machine shop to clean up some minor pitting & corrosion on the cylinder walls.

    I'm handy with a wrench, and know how to time VANOS, etc. I will not necessarily be building this motor myself. I figure at least getting the rotating assembly balanced is a good start.

    Please give me your thoughts on this build! Thanks guys!
    Kingston
    ‘Tis by the grace of God that my cars run!


  2. #2
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    Honestly most any time you go for more power you are risking reliability.

    The he mods you listed open a Pandora's box of how far do you want to go with this engine? If reliability it what you want, the only mods I would recommend would be an S54 dual pick up oil pump and S54 oil pan. Either weld/wire the oil pump nut or send it off to VAC for their shaft upgrade.

    Going stiffer springs isn't really necessary unless you're planning on running non stock cams, high compression or revving the engine to very high rpms. The pistons and rods can save you some rotating weight but your stock stuff can handle all the Power an NA engine will throw at it.

    Honestly new stock rod bolts, head bolts etc will be plenty. Again, if you're not running boost these stock parts are plenty strong and OEM is almost always gonna be the mods reliable.

    - - - Updated - - -

    Oh and run an oil cooler (you can get an s54 oil filter housing to do this). Keeping your oil from turning to water is the best thing you can do to protect the engine internals and keep from spinning a bearing etc

  3. #3
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    Agree, i think you already have it. I'd focus on cooling (water and oil) and oil starvation prevention (baffles, pumps, etc).
    Last edited by TXBDan; 08-25-2014 at 02:53 PM.

  4. #4
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    If using stiffer valve springs I would recommend upgraded valves as well. Of course I beat on these for 4 years with no problems.
    Last edited by eye145; 08-25-2014 at 10:33 PM.

  5. #5
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    Stock valves are two piece and are known to separate, as you can see above it will destroy an engine if it fails. A set of Supertech valves doesn't cost that much.

    Sent from my GTX3582R
    '97 M3, Estoril blue, 2 dr, euro 6-spd, EFR 9180 divided T4 .92 IWG, RK tuning, CP 8.5:1 pistons, Eagle rods, Schrick cams, L19 11 mm ARP studs, O-ringed block, Supertech stainless/inconel valves, Supertech springs & Ti retainers, ported head, S54 oil pump/pan, 80 lb. injectors, OBD1 intake manifold, Steedspeed twin scroll T4, 3.5" SS exhaust, eBoost2 EBC, HFS-4 W/M injection, AEM Failsafe, Zeitronix data logger, Racelogic TC, OpenOBC w. ethanol %, Ireland Eng. engine mounts, UUC black tranny mounts w. enforcers, UUC twin disc feramic, ARC-8's, MCS 2-ways, Z3 rack, Rallyroad strut bar, X brace, Eibach sway bars, Ground Control LCAB bushings, Bimmerworld RTAB's, Powerflex subframe bushings, 210 4-clutch LSD, Stoptech BBK, titainium shims, steel braided lines, brake cooling ducts.

  6. #6
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    I can give you a lot of advice as I used to work for VAC Motorsports, a BMW race engine shop - and I saw a lot of failures. I also race an M50 based engine that has been reliable for many seasons.

    Here are the "must haves":

    Oil pan baffle - you will starve the engine under heavy breaking without one.
    Oil pump upgrade kit WITH safety wired bolt - currently only 1 shop sells this piece with the safety wire option, but it can be easily retrofitted to a kit that does not have it.
    Stronger Rod bolts - ARP 2000
    Lower temp thermostat
    Genuine BMW head gasket (not Victor Reinz).
    External Oil Cooler

    That's it. The engine will be reliable if shifted under 6800 and no over-revs.

    Since you are running stock cams, I wouldn't worry about valves or valve springs unless you can detect valve float due to valve spring fatigue.

    If you want to make more power, it's a very slippery slope.

  7. #7
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    Quote Originally Posted by Clubsport View Post
    I can give you a lot of advice as I used to work for VAC Motorsports, a BMW race engine shop - and I saw a lot of failures. I also race an M50 based engine that has been reliable for many seasons.

    Here are the "must haves":

    Oil pan baffle - you will starve the engine under heavy breaking without one.
    Oil pump upgrade kit WITH safety wired bolt - currently only 1 shop sells this piece with the safety wire option, but it can be easily retrofitted to a kit that does not have it.
    Stronger Rod bolts - ARP 2000
    Lower temp thermostat
    Genuine BMW head gasket (not Victor Reinz).
    External Oil Cooler

    That's it. The engine will be reliable if shifted under 6800 and no over-revs.

    Since you are running stock cams, I wouldn't worry about valves or valve springs unless you can detect valve float due to valve spring fatigue.

    If you want to make more power, it's a very slippery slope.
    Clubsport - somehow when I posted this thread, I missed seeing that you had replied. Thank you for your repsonse - I have done all of these things on my new build, minus the ARP rod bolts. I still have the motor on a stand, so I think I will flip it over and do those, too.
    ‘Tis by the grace of God that my cars run!


  8. #8
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    That's a strong setup. If you are concerned about reliability, go over the tune with a wide band.

  9. #9
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    Quote Originally Posted by kingston View Post
    Clubsport - somehow when I posted this thread, I missed seeing that you had replied. Thank you for your repsonse - I have done all of these things on my new build, minus the ARP rod bolts. I still have the motor on a stand, so I think I will flip it over and do those, too.
    Do know what you're doing when it comes to that? It's not as simple as turning wrenches. You can do more harm than good. Your stock components won't come close to their yield at the power levels and rpm you will be exposing them to. On the other hand, changing fasteners without checking distortion is dangerous. The proper way to torque rod bolts is by stretch and even then I've found ARP usually gives too high a torque value which is fine if you're going to line hone the motor torqued down but if you don't and you don't bore gage the rods after torquing the bolts you may distort the bores and if you don't at least plastigage, you will end up with too small clearances and not know it.

    Again, if you know all this, please disregard. Otherwise, leave well enough alone internally and focus on keeping the fluids happy (oil baffles, oil cooling, and if you're truly after longevity, ATI damper and dry-sump).

  10. #10
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    It seems like you've covered most of the main bits. I'd say my quick list is:

    -S54 / euro M3 oil pan dual sump pickup / pan setup
    -oil cooler
    -stewart water pump + lower temp thermostat
    -good ducting + radiator setup. Make sure the air actually goes through the radiator. Path of least resistance and all that jazz.
    -welded/wired on oil pump nut
    -one piece valves
    -upgraded valve springs /retainers (not mandatory, but a nice piece of mind for a 7200rpm engine that will see the redline all the time.) I never had a stock valve failure/separation, even with upgraded Supertech springs/ti retainers but I imagine if I kept at the limiter enough more drifting one would've eventually failed and ruined the entire engine, so I went ahead with the one piece valves as well.
    -ATI press-fit damper if you really want to be nice to it, but on an NA engine at 7200rpm or less, the harmonics shouldn't be harsh enough to need it. You will have extended bearing life on a race engine with the ATI, however.

    Mike
    IG: @mikevanshellenbeck

  11. #11
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    I think at some point you have to balance the cost of reliability against the cost of what it is you're trying to protect. No one wants to waste a track weekend with a blown motor, but how much are you willing to pay to save a $1500 motor and a $500 weekend?

  12. #12
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    Quote Originally Posted by TXBDan View Post
    I think at some point you have to balance the cost of reliability against the cost of what it is you're trying to protect. No one wants to waste a track weekend with a blown motor, but how much are you willing to pay to save a $1500 motor and a $500 weekend?
    Exactly..... especially with how cheap these motors have gotten. Dual sump would be nice but it costs more than a replacement engine....

  13. #13
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    That sounds simple in theory except in reality:
    - if you are actually competitively tracking the car you've just lost all your contingency opportunities for the weekend, goodbye $1500 worth of free hoosiers
    - a $1500 motor (lets assume you have one on the shelf otherwise you're hunting for a fair deal on one and that's down time)
    - $350 misc stretch bolts, new gaskets etc that you replace on an unknown motor.
    - 1-2 weekends to swap the new motor in (assuming you're doing this yourself otherwise you have the cost of paying someone to swap it)
    - the $3-500 cost of new oil lines, cooler etc now that your junked motor has introduced metal shavings into the rest of the system
    - you pray that whatever craigslist/forum member you bought the motor off of didn't lie about the engines condition (i.e. get the engine in the car and find it has a mechanical issue)
    - the cost of fluids, while small if we're saying a $3-500 dual sump setup is too costly then surely $100 worth of oil and coolant should be considered

    It sounds like the PO is mostly just using this for HPDE but there are lots of situations where it's more than worth spending $1500 in reliability upgrades on a $1500 motor. Even if you ignore contingency in my above example I'm seeing a $1500 motor, $350 in parts, $300 for a oil system refresh, $200 in labor if you value your time at $10 an hour and $100 in new fluids you're talking truly almost $2500 to just "drop" another s52 in and be able to expect it to do any type of track use.
    - Brad


  14. #14
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    I personally pursue reliability for an even more fundamental reason - personal safety. I have a friend who had a rod break on Calabogie doing 150mph into Temptation. The rod ventilated the block and ripped a drysump oil line in half, which sprayed oil over the right front wheel making trying to slow down interesting... and as he did the oil caught fire. He and the car ended up OK but that's a failure which could have ended very badly. Even without that kind of drama, I wouldn't want an engine that is connected to my rear wheels seize up going through a fast turn at full song.
    Last edited by TheJuggernaut; 02-22-2017 at 04:06 PM.

  15. #15
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    a few years ago an IP E36 M3 bent a frame rail from hitting the wall after the car in front of him windowed the block from a stock rod bolt failure and put oil all over the track.

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