Cosworth YB Cylinder Head and Block

In the Eighties and Nineties the Cosworth YB engine became an icon of high performance. Now the cylinder heads and engine blocks for this famous classic engine are available from Cosworth through Co-ordSport .

Using the original drawings and the wealth of experience that resides at Cosworth the company has reintroduced the legendary YB head as fitted to the Ford Sierra and Escort Cosworth.

The heads are recast and machined in United Kingdom to the high level of quality customers have come to expect from Cosworth.

The new YB head is a hybrid allowing fitment to both 2 and 4WD vehicles and features:

• Cast Turbo Brackets
• Combustion Chamber Machined to 50.4cc (4WD specification)
• Valve Seat in Brico LXW 35/D-HT
• Exhaust Valve Guides in Brico Sintered Composite MXP28 (Cu filled)

The cylinder heads (part number YB8069) are in stock and available through Co-ordSport with a retail price of £2,100+VAT.

The Ford Cosworth YB aluminum cylinder block is a direct replacement for the European spec thick deck 200 iron block and can be used for 2 or 4WD wet sump or dry sump applications.

Cast from LM25 and heat treated to T6 condition for uncompromising strength, the block is intended for normally aspirated or turbocharged engines. The large, robust shot peened cast alloy main caps are located with precision ground ring dowels and secured using a 12 mm high strength stud, washer, and nut kit.

The thick-wall bores can accommodate dry iron straight thin wall liners in 90.8mm, 92mm, 94mm, and 96mm or the bores can be left unfinished allowing other liner types to be installed. Additionally, crankshafts up to 88mm stroke with high performance rods are acceptable. The deck height is finish machined to original specification 207.5mm, but is also available with a 217.5mm deck for long rod and/or stroker crank application.

Unlike the iron block with limited material beneath the threaded head bolt/stud holes, this block features large cast pillars that extend internally from the deck to the crankcase portion of the block, which permit the threaded stud holes to be machined deep into the block; however, the stainless steel threaded inserts are installed at a depth to accommodate standard head bolts or an aftermarket head stud set. The combination of large internal pillars, thick cylinder walls and deep cast deck provides a very strong and stable block making through block stud arrangement unnecessary.

Features:

• 90.8mm Bore Alloy Block
• Weight: 47.15 lbs (this includes the liners, bungs, core plugs, studs, ring dowels, thread inserts, and main caps)
• LM25 Heat Treated Aluminum
• Robust Shot Peened Alloy Main Caps
• Dry Iron Liner
• 12mm Main Studs
• 90.8mm or 94mm

 The cylinder blocks (part number 20000147) are made to order and available through Co-ordSport with a retail price of £6,404.46+VAT.