Valve guides. Over time valve guides get worn and damaged and it essential as part of a full engine rebuild to ensure valve seats are to the correct tolerance. Along with the valve spring, it serves to positively locate the valve so that it may make proper contact with the valve seat.
A valve guide is a cylindrical piece of metal, pressed or integrally cast into the cylinder head, with the valve reciprocating inside it. Guides also serve to conduct heat from the combustion process out from the exhaust valve and into the cylinder head where it may be taken up by the cooling system. A balance between stiffness and wear on the valve is essential to achieve a useful service life. The clearance between the inner diameter of the valve guide and the outer diameter of the poppet valve stem is critical for the proper performance of an engine. If there is too little clearance, the valve may stick as oil contaminants and thermal expansion become factors. If there is too much clearance, the valve may not seat properly and excessive oil consumption can occur.
Here at ASD engines we understand this important aspect and use a Serdi 3.5 Seat cutting machine.
In the picture we have a Mustang drag racing engine being inspected after a catastrophic failure. Firstly we fully disassembled the engine and thoroughly cleaned it with our high pressure system. Guide seats were then re cut using our Serdi machine.
If you need engine reconditioning in Yorkshire or Lincolnshire we can offer a collection service subject to availability.
Call us or email us today.
ASD Engines Ltd
3 Balby Road