Engine & Performance

Whether you have a street cruiser or an all-out racecar, performance and reliability is important! Our OEM and forged-engine programs help ensure you are getting the most out of your ride, tailoring the build to your application and needs. 

Leroy Engineering OEM and Boost-Ready Engine Builds

Whether you need a restored OEM engine to keep your car on the road or a built and race-ready track monster, we’ve got you covered!

For Our OEM Rebuilds

We use all Mazda OEM parts to take your motor back to exactly how it left the factory… or better.

Each motor is disassembled, cleaned, and inspected. The crank, block, and head are measured to ensure they can be reused. The block gets bored and honed for the new pistons (up .25mm from the previous size), the deck is resurfaced, and the block is painted OE black. The head is resurfaced and valve seats are ground down (and replaced if needed). Crankshafts are polished and balanced. We replace the oil pump, water pump, bearings, gaskets, pistons, and rings with Mazda OEM parts. All external pieces are painted or powder-coated to your choice of colors. Injectors are cleaned and/or replaced.

For Our Forged Builds

Everything gets upgraded! We rate our boost-ready builds at 450 HP capable, but that’s only because we haven't tested beyond that to find the actual HP limit. Built motors are more customizable than OE builds, depending on your application. We design-in the correct compression ratio, clearances, and rates for the application. And we will walk you through the installation to ensure it integrates with the rest of your system.

Our standard boost-ready engine includes forged rods and pistons, ARP main studs, rod studs and head studs, a billet oil pump, and a Fluidampr balancer. Blocks are align-bored, resurfaced, bored, and honed. Heads are decked to meet the target COMP ratio. Optionally, oil pans can be fitted with welded -AN drain fittings, upgraded dampers, valve springs, camshafts, timing gears, etc. depending on the need.

BP Engine Pricing and Definition

Long Block: Oil pan to valve cover, a complete short-block plus rebuilt head, timing belt, valve cover—everything assembled, timed and ready to drop in.

Complete Engine: A long block plus intake manifold, injectors, throttle body, plugs and wires, coil pack, and temp sensors. A plug-and-play drop-in.

Core: A used engine that will be rebuilt. This includes all the pieces to be restored and reused. If parts are missing, no problem! We can source them separately.

 

(Prices assume a buildable core is provided.)

BP OEM Street Rebuilds

Long-block: $7,250

Complete engine: $8,500

BP Forged Boost-Ready Engines (Competition Use Only)

Long-block: $9,250

Complete engine: Call for quote

Ordering Process

The first step is to send us an email or give us a call. We want to learn all about your application and will put together a build sheet that meets your needs. Everything from fuel type, compression ratio, and HP targets to colors and cosmetic options.

Next, you will ship your engine to us (if you are sending a core). Ideally, we’d like the engine fully assembled (this prevents loosing parts). We will disassemble the motor and determine why it failed (if it did). We can then order the parts needed for the rebuild and update your build sheet if needed.

Ideally, we can have an engine turned around in about 3 weeks. However, with the current lead-time for parts, we are realizing closer to 5-8 weeks at present. We do not require any payment up front and will bill monthly. If your job stretches out into multiple months, you will receive an invoice at the end of each month that can be paid online.

Engines can be picked up at our shop or we can ship them to you. Freight for an engine is usually around $350.

 

Diff Rebuilds

Our diff rebuilds involve replacing everything in the diff including seals, bearings, and, if needed, gears and carrier. We can upgrade to an LSD or put it back to OEM spec. We can also supply all needed pieces including new gearsets, Torsen center sections, and housings. 

 

List of other performance services:

 Interior

  • Roll bar installation
  • Racing seat installation
  • Custom carpet and door cards
  • Steering wheels
  • Gauges

Cosmetics

  • Engine bay cleanup
  • Powder coating
  • Vinyl graphics (race livery, numbers, class)
  • Soft top replacement

    Suspension

    • Coil-over install
    • Race alignments and corner balancing
    • Tire mount and balance
    • Fender rolling
    • Sway bars
    • Bushings
    • De-powered steering racks
    • Brakes

    WARNING: NOT ALL PRODUCTS AND SERVICES NOTED ARE EMISSIONS LEGAL FOR STREET USE; SOME ARE INTENDED FOR USE ONLY IN RACING/COMPETITION MOTORSPORT VEHICLES. Visit https://leroyengineering.com/pages/emissions-guide for more details.

    Contact Leroy Engineering