A BRZ, FR-S or 86 left the factory with a naturally aspirated FA20 (Toyota's listings call the same engine the 4U-GSE), and sooner or later a lot of them get a turbo or a supercharger. The stock engine can take a bolt-on kit, but once the plan is real boost, most owners end up pulling the engine and building it. This FA20 engine build parts list is for that moment: what to do while the engine is apart, in what order, and which parts we carry for each step, with every fitment detail taken from the product listings themselves.
Who this FA20 list is written for
You own a 2013–2016 Scion FR-S, a 2013–2020 Subaru BRZ or a 2017–2020 Toyota 86, you are adding forced induction, and you want the engine apart once rather than twice. You have a machine shop lined up for measuring and bore work and a clean bench for the rest.
Two engines sit just outside this list. The 2015-and-later WRX runs a turbocharged FA20 (FA20DIT) that shares some parts here, such as the ARP head studs and King rod bearings, but not all of them. The 2022-and-later BRZ and GR86 use the 2.4L FA24, and most listings below stop before those years. Whatever you drive, match your exact year and submodel against each listing's fitment table; our guide on checking fitment before you order shows how.
The build sequence, bench to first start
- Settle the power plan before buying a single part. Turbo or supercharger, target boost and fuel decide the piston, the head gasket thickness, the injectors and the pump. Choosing those last is how builds end up with a second parts order.
- Tear down and measure. Strip the block, measure bores and crank journals, and inspect the castings. Standard bearings suit a crank that measures in spec; a ground crank needs the matching size step, explained in Engine Bearing Sizes Explained. Reinforcement supports the cylinder walls of a sound block. EPOXY54 is not a crack repair.
- Bore to the piston, not the other way around. Stock FA20 bore is 86 mm. The Manley set below is an 86.25 mm bore, so have the pistons in hand and let the shop bore and hone each cylinder to suit them.
- Buy both head gaskets now. A boxer has two heads, so you need a left-hand and a right-hand gasket. Have them on the bench before the block is reinforced, because the head gasket is used as the template when the coolant passages are drilled back through.
- Reinforce the open deck. The FA20 is an open-deck block. EPOXY54 gives it closed-deck strength without machining: 21,000 psi compressive strength, thermal expansion closely matching aluminum, and a DIY install in 5 steps. Choose the Flat 4 configuration, with Partial Fill for a street car. The FA20 closed deck conversion page covers the platform in more detail.
- Assemble the short block. After a thorough clean, fit the main bearings and crank, then the rods with fresh rod bearings, then the pistons. Check clearances as you go.
- Service the heads while they are off. Upgraded valve springs and retainers are easiest to fit now. Then the heads go on with gaskets and studs, torqued to ARP's instructions. What Head Studs Fix, What Block Filler Fixes explains why a boosted build uses both.
- Fuel, oil temperature and clutch go in with the engine. Fit the pump module and injectors, the oil cooler and the clutch before the engine is back in the car, then hand it to your tuner.
FA20 parts we stock, by stage
Every fitment note below comes from the listing. All parts are in our Subaru FA20 collection.
| Stage | Part | Why it's on the list | Link |
|---|---|---|---|
| Block | EPOXY54 Aluminum Block Epoxy Kit (Flat 4) | Supports the free-standing cylinder tops; Partial Fill keeps OEM coolant capability, Dry Block is for track use only | View |
| Block | EPOXY54 Install Kit (non-V) | Stir stick, 5/32" drill bit and squeeze bottle; masking tape and sugar or salt are not included | View |
| Pistons | Manley 2013+ BRZ (FA20) 86.25mm bore 11.4cc dish Platinum Series set with rings (632602C-4) | 2618 alloy forgings with a dished crown; bore the block to suit | View |
| Rods | Brian Crower 4UGSE 5.094in I-Beam Extreme rods with ARP Custom Age 625+ (BC6616) | Forged rods in place of the factory rods; listed for the FR-S, BRZ and 2017 86 | View |
| Rod bearings | King FA20 pMaxKote Performance rod bearings, STD (CR4616XPGC) | Coated performance set for a crank that measures standard | View |
| Main bearings | King Subaru FA/FB main bearing set, STD (MB5745SI) | Fresh mains while the crank is out; table covers BRZ, FR-S and 86 | View |
| Gaskets | Fel-Pro FA20 conversion gasket set (CS26524) | Every gasket for lower-engine work, per the listing | View |
| Head gasket | Cometic FA20 89.5mm bore .050" MLX, left side (C4589-050) | Multi-layer stainless with Viton coating; pair with the right side | View |
| Head gasket | Cometic FA20 89.5mm bore .050" MLX, right side (C4588-050) | The matching right-hand gasket | View |
| Head clamping | ARP Subaru FA20 2.0L head stud kit (260-4301) | Studs in place of factory head bolts; listed for the BRZ, FR-S, 86, 2015 WRX and Forester XT | View |
| Valvetrain | GSC P-D single beehive spring kit, titanium retainers, chromoly seats (5056) | Spring upgrade fitted while the heads are off; listed for 2013–2017 BRZ, FR-S and 2017 86 | View |
| Fuel | DeatschWerks Bosch EV14 1200cc injectors, set of 4 | Higher-flow injectors for a boosted fuel map; listed for BRZ, FR-S and 86 | View |
| Fuel | DeatschWerks X2 pump module with dual DW300 (9-301-7051) | In-tank module with two pumps; listed for 2013–2016 FR-S, 2013–2020 BRZ and 2017–2020 86 | View |
| Oil | Mishimoto BRZ/FR-S thermostatic oil cooler kit | Direct-fit cooler in the front bumper with braided lines and a billet sandwich plate | View |
| Clutch | ACT FR-S/BRZ HD/Perf Street sprung clutch kit (SB13-HDSS) | Heavy Duty pressure plate with ACT's Performance Street organic disc | View |
Where FA20 builds trip up
- Ordering one head gasket. Cometic sells the left and right sides as separate listings with separate part numbers. A flat four needs both, in the same thickness.
- Reading only the rows you expect. Some Cometic fitment tables also list unrelated vehicles. Go by the FA20 in the title and the BRZ, FR-S or 86 rows that match your car.
- Assuming a WRX part fits the BRZ, or the reverse. Both say FA20, but the WRX engine is a different version. Manley, for one, sells separate WRX (FA20F) and BRZ piston listings.
- Buying for a 2022+ car from 2013–2020 listings. The newer BRZ and GR86 run the FA24. Several tables above end at 2020 or 2021.
- Leaving fuel until after the tune is booked. Injectors and pump are sized from the power plan in step one, so they belong on the first order, not the last.
Want the background on the block itself? FA20 Closed Deck Alternative covers reinforcement options and cooling for this engine, and Open Deck vs Closed Deck Block explains why the deck design matters under boost.
Build the FA20 once
Plan the power, measure, bore to the pistons, get both gaskets, reinforce, then assemble. Start with EPOXY54 in the Flat 4 configuration, add the Install Kit if you need the tools, and email support@epoxy54.com with your year and model if you want a second check before ordering.
Ready to order? Shop the FA20 build stage by stage, with every part on one page.