Shim under lifter, Pros & Cons

Discussion in 'E36 M3 (1991-1999) and E30 M3 (1986-1990)' started by M3turbo, Nov 29, 2019.

  1. 29 Nov 2019 at 8:27 AM #1
    M3turbo

    M3turbo A mere Chipper

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    The current setup i have on my S50B30

    PPF 284 Cams
    3.0L Buckets
    Very thick shims

    As the cams are regrinds, the lift is made by grinding the back of the cam and adding thicker shims.

    I was given NO information at all from PPF about the cams only and i quote;

    "we use stock shims and rev them to 9000-10,000+ no problem"
    "just set lift to 1.5mm @TDC"


    Now I've been told from a very reliable source that this is simply not true, due the the extra thick shims some where in the region of 4mm that anything over 7000 is risky.

    I want ultimate reliability and also the ability to rev it to 8500 SAFELY


    There is the option of going to 3.2 buckets as they wouldn't require as thick of a shim or do i just go the whole hog and fit shim under lifter?

    absolute PITA to set clearances however, but not as as as if it spits a shim out and wrecks the cams etc (I've had that happen on a totally stock s50b32) At sub 8000 rpm
     
  2. 29 Nov 2019 at 10:23 AM #2
    Iain

    Iain Staff Member Moderator

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    I think ultimately the cams are junk and even with shim under you could get float as you are going to need either a very thick bucket or shim. i am somewhat dubious that you will even get a kit to fit.

    I think if you want 8.5k you have only one real option, which is shim under. But i question the viability of the cams.

    There are lots of other options of course. i ran 8100 with evo head, thin shims on tall evo buckets on an evo head with catcams, its still running and has been for years.

    If your really worried you can tack weld the shims to the buckets, but even doing that you are going to have a problem with inertia Vs Speed if the train weight is too high.
     
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  3. 29 Nov 2019 at 3:47 PM #3
    M3turbo

    M3turbo A mere Chipper

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    I do have PPFs valves and upgraded valve springs perhaps they can cope with the inertia, but i would obviously prefer it if the valve train was lighter.

    The thought of tack welding the shims did cross my mind but i'd imagine even doing it with tig it may pull slightly as it cools.

    Or i buy a set of cat cams and go with tall evo buckets or cat cams & shim under lifter.

    The car is turbo'd with a twin-scroll PT6766 so that extra 1000rp up top will make a huge difference.
     
  4. 29 Nov 2019 at 11:50 PM #4
    Iain

    Iain Staff Member Moderator

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    I have to be honest i think your going to run into a lot of broken parts at 8500, rods particularly and the crank damper.

    8k ish and you will be ok IMO, bear in mind that the force on the rod will increase as a square, not linear.

    You will also (if you dont already have) need an evo sump and punp as at that rpm you will have return issues, i would also look the girdle the crank mains.
     
  5. 30 Nov 2019 at 7:28 AM #5
    M3turbo

    M3turbo A mere Chipper

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    I probably should have mentioned the spec,

    Fully forged & dynamically balanced
    PPF Valve spring kit
    PPF Valves
    PPF Mains girdle
    ARP throughout
    EVO/s54 Oil Pump & Sump

    PPF 284 Turbo grind cams.

    Athena cut ring gasket
    WRC Design equal flow plenum
    UUC twin plate clutch
    875cc injectors.
    6x EGT sensors
    Wide band lambda
    Delta ECU
    king bearings
    Oil feed to head restrictor (Not entirely sure if this is required as bmw updated the block at a certain point so potentially it isn't required)



    Pretty much a no expense spared
     
    Last edited: Nov 30, 2019
  6. 1 Dec 2019 at 3:21 AM #6
    Iain

    Iain Staff Member Moderator

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    what pistons and rods? Forged doesnt really mean all that much as most are rather heavy and to be honest the sintered oem ones from the later spec evo are probably better in terms of rpm stress and resistance to cap walk, either way I would go for 8k/8.1k running the delta you can just re key the rpm limit at any point, but i would certainly stress test the crank balancer, depending on what you started out with you may just want to swap it if there are any signs of cracking as they tend to take the crank sprocket out too, though the evo one should be better than the 3.0

    I don't know what head your running, if its a 3.0 head you will need to change to the group n valve in all but the latest cars, if its an evo head your fine and its not required.

    I would still look to reduce the train weight as much as possible, you don't want the inertia or ho have the run springs so hard they want to snap the valve head off.

    The above is of course just my opinion.
     
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  7. 2 Dec 2019 at 10:56 AM #7
    M3turbo

    M3turbo A mere Chipper

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    Your Motor:
    e36 m3 turbo 1996
    Rods ~515g
    Pistons ~312g

    It is a stock 3.0L crank damper, could i upgrade this to something like a VAC one?

    It is a 3.0L Head with the grpN restrictor.


    The valve springs are already quite stiff and came as a set form PPF

    http://server.pure-pf.com/webshop2/en/valve-spring-kits-bmw/1751-ventilfj├Ąderkit-s50b30-euro.html

    http://server.pure-pf.com/webshop2/...ch-s50b30-1mm-inconel-exhaust-valvevalve.html


    I think the 3.2 buckets and shims, along with cat cams would be the only way to go to reduce the weight the most.


    Does anyone have any dealings with PPF? as there really isn't that much information on their stuff.
     
  8. 2 Dec 2019 at 8:02 PM #8
    Iain

    Iain Staff Member Moderator

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    Both are quite light depending on how they are weighed, stock rod is 620 with bolts or 556 without and the stock b30 piston is 458 with the wrist pin or 347 without.

    3.0 head is a little less ideal as the intake valves are not waisted vs the 3.0 that are, so a little more weight and a little less flow.

    Springs must be very stiff if just the outer is more than both the oem ones.

    No dealings with ppf myself.

    I would agree that catcams shims and lifters will get you closer to where you want to be, i would still creep up on it rather that diving right in at 9k.

    Balancer wise you could but i think a used evo one will get you most of the way and the vac ones are bloody expensive.
     

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