Ford Cosworth YB – Long Stud Conversion

Call us for expert advice and a quotation for your engine machining requirements.

The original cylinder head bolt arrangement on the Cosworth YB engine block found in Ford Sierra and Ford Escort applications can cause distortion both to the block deck surface and to the cylinder bores.  In extreme cases this can lead to cracking between the head bolt threads and the adjacent waterways. 

A solution to these problems is achieved by modifying the stronger Cosworth 200 series cylinder blocks to accept a long stud conversion which eliminates the stresses that the cylinder head torque puts on the top of the block.  The cylinder block is machined to allow the replacement long studs to pass through the deck face and thread directly into the block at the bottom of the water jacket. An added bonus with long studs is that the upper cylinder bore wall is not so affected by head bolt stresses.  After machining the block deck face is then resurfaced to ensure that it is completely flat before being returned to service.      

For engine of up to 500hp a 6 stud conversion should suffice but for engines making in excess of this a 10 stud conversion is also available.


There are several different manufacturers producing stud kits for these engines and at H T Howard we have developed a range of dedicated tooling to perform the operations required to successfully machine your engine block to accept any of the range of studs available.


We have carried out many conversions for one of the top Sierra / Escort Cosworth tuning specialists and we can offer the same engineering excellence for your engine. 


Call us for expert advice and a quotation for your engine machining requirements.