Mazda FS Builder's Guide

 

  1. What do I need to build a high performance FS motor for boost?

    For block only :
    rods, pistons, engine bearing kit, ARP main & head studs, Cometic MLS head gasket, OEM Mazda oil pump, OEM Mazda rebuild kit, oil jets, clutch, flywheel
    see http://www.crossoverauto.com/mazdaspeed3.htm and see http://www.crossoverauto.com/mazdaspeed6.htm

    For full motor :
    All above, 1mm oversize valves, valve springs (single or dual depending on application, titanium retainers, oil seals, custom profile cams.
    see http://www.crossoverauto.com/mazdaspeed3.htm

  2. What compression pistons should I use?
    How much boost do you plan on running and what size turbo?
    i.e. The GT28RS supports 20 psi efficiently. So stock compression will be good for this setup.
    If you choose to run bigger or more boost lower compression should be used.

  3. What do I need to get done at the machine shop for my block?
    Cylinder hone, main bore align hone with the ARP main studs, balance crankshaft, rods, pistons, replace freeze plugs, clean everything. Decking the block or overboring the cylinders is only necessary if the block is damaged.

    For the cylinder head:
    Full clean, 3 or 5 angle valve job, replace oil seals, check clearances
    If desired: install performance valves, springs, cams, port and polish work if desired.

  4. What torque specs should I use?
    Use the specs supplied by the rods, and ARP. Only use OEM specs when using OEM fasteners, ARP hardware needs to be torqued and loosened a 2-3 times before final torque sequence. Customers who purchase their parts from us can request the torque sequences from our tech department. Your order # will be required at time of request.

  5. How should variances be on the balance?
    At least within 1 gram variance, .5 is even better.
    However, unless you are going to doing the balance just tell your machinist to get it spec'd close as possible for a performance build.

  6. What should piston ring gap be?
    1st and 2nd ring gap depends on your setup and application, big boost applications, nitrous requires larger gaps
    The oil rail usually use the factory specs. Check your ring supplier for any specifics on installation such as which side is up and ring gap positions.
    There usually is a mark on the ring which says which side faces up. It is important to check how the oil rail ring needs to sit per the instructions.
    If the gap positions are not specified use the OEM ring gap placement.

  7. What should the piston to wall clearances be?
    Follow the piston manufacturer's recommendation

  8. Where can I cut corners to save money?
    Do you want a reliable engine and built to last longer than stock? Do not cut corners. If you can't afford to do it right the first time, buy a used motor to drop in instead if you blew your engine and can't afford to build it correctly.

  9. How should I change the oil during break in?
    1st change: after 15 -25 mins of operation if build was in a dusty or dirty location, otherwise before 50 miles is good.
    2nd change: at 500 miles
    3rd change: at 1500 miles
    Final breakin change: at 2500 or 3000 miles
    Use a new filter each time and 5w or 10w30 conventional oil. Switch to synthetic after break-in if desired.
    It is a good idea to buy and install an oil magnetic drain plug which are available through us, before first fill and startup.

  10. How should I drive the car during break in?
    After first startup and warm up, drive to a safe area where you can accelerate to 60-65 mph and engine brake (letting off the throttle but not pressing the brake pedal) down 25 mph repeat until you do this about 15 times. This helps seats the rings. After this, vary the rpm and load, open it up occasionally. Be sure to warm up the engine before taking off on cold starts. Check oil and coolant levels frequently during break-in.