The IAG Trojan Short Block starts with brand new Subaru 2.5L engine case halves.
IAG machines the case halves assembled together in our Haas VF-4SS CNC mill to accept the IAG CLOSED Deck Inserts that transform the block into a solid deck. The unique inserts feature small passages that allow needed coolant flow to the deck surface. The case halves are then CNC machined with O-ring receiver grooves around the bore surface as well as drilled and tapped to accept 1/2" head studs that greatly reduce head gasket failure during high cylinder pressure scenarios. Next, the short block is Deck Plate bored and honed to 99.75mm in our in-house Sunnen SV-30 the most advanced automotive cylinder hone available. IAG‘s in-house honing process is able to set custom piston to wall clearances to best fit your needs.
The modified case halves are then assembled using a new 2017+ Subaru 2.5L nitride treated STI crankshaft that is matched to ACL or King race main bearings. IAG-Spec Tuff H-Beam connecting rods and ARP 625+ rod bolts are utilized along with ACL or King race rod bearings. The case halves are sealed with new OEM main/case bolts and sealant. Finally, IAG-Spec 99.75mm JE FSR 2618 Forged Pistons and electroless nickel plated tops and ring area as well as upgraded .250" / .906" H13 wrist pins are added to finish the Trojan short block. Additionally, all IAG-Spec piston skirts utilize the JE Perfect Skirt coating.
The IAG Stage Trojan Closed Deck Short Block has a power output rating of 750BHP.
Stage Trojan Closed Deck Includes:
- Case Halves - Converted to Closed Deck using brand new Subaru OEM case halves, bored and honed to 99.75mm.
- O-Ringing - Machine and O-Ring Deck Surface
- Head Studs - Machine Case to 1/2" head studs - * Head studs are sold separately
- Pistons - IAG-Spec JE FSR 99.75mm 2618 Forged Pistons, Electroless Nickel Plated Tops & Ring area, Ring Set, .250" / .906" H13 Wrist Pins, Clips, (Perfect Skirt Coating and Offset Wrist Pins)
- Crankshaft - Standard New Subaru Nitride Treated 2017+ STI Crankshaft.
- Case / Main Bolts – Standard FHI Subaru case bolts.
- ACL or King Rod Bearings
- ACL or King Main Bearings
- IAG Spec Blueprint Sheet
- 8.5:1 on D Cylinder Heads (EJ255)
- 8.2:1 on B, V and W EJ257 Heads with standard thickness gasket.
Head Gasket Recommendation:
- JE Pro Seal .039 inch Head Gaskets - (PN# SB1001-039 for D25 & B25 Heads, PN# SB1003-039 for V25, W25 & N25 Heads)
- All IAG short blocks are balanced and blueprinted.
- If you are reusing your original wrist pin service plugs and covers always replace the (3) OEM wrist pin plug washers and (1) wrist pin service cover O-ring before installing a short block to avoid potential leaks.
- Never reuse a rear main seal on a new short block.
Not planning on reusing your original short block service plugs and covers? IAG offers a simple comprehensive cover and seal kit that includes (1) Rear main seal, (3) OEM wrist pin plugs, (3) OEM wrist pin plug washers, (1) OEM separator cover, (6) OEM separator cover bolts, (1) OEM wrist pin service cover, (1) OEM wrist pin service cover O-ring and (2) OEM wrist pin service cover screws.