Pressure Testing
The cylinder head is tested at pressures of up to 60psi to ensure the casting is sound. This is carried out on our dedicated Delta 6000S/L test rig and will show up any faults through which water could enter the combustion chamber or port areas and anything which could cause water and oil cross contamination.
Valve Grinding Machine
Valves
All valves will be checked for alignment and valve stem wear and replaced if not serviceable. Those that are still within specification will be cleaned, valve refacer will be refaced and have the stems polished and tips refaced if necessary.
Valve Guides
Each valve guide will be checked for size, ovality and valve clearance. Any non conforming guides will be reworked or replaced as necessary. Valve guides can be restored to the correct specification using several different methods. These can include the fitting of bronze guide liners, thin wall type guides or full replacement.
Valve Seats
All valve seats are recut using dedicated single point carbide cutters which are selected to best match the original valve seat angles. Where possible, each valve seat is cut with a minimum of three angles for improved flow.
Damaged valve seats can be replaced where necessary using replacement valve seat inserts.
Head and Block Refacing Machine
Head and Block Refacing Machine
Refacing
The cylinder head gasket mating face is machined . Using diamond single point technology we are able to achieve the very fine surface finishes required by the Multi Layered Steel head gaskets used in many modern engines. Cylinder heads containing mixed materials like those found in older indirect injection diesels with hardened pre-combustion chambers can be reground.
Preparation
Following final machining, bolt threads will be checked and cleaned out while studs will be checked to ensure their threads are good. All traces of old gaskets and sealants will be removed and gasket faces will be cleaned to remove any burrs that might prevent a good seal.
Assembly
After all machining work is completed the cylinder head will be washed for a final time to remove all traces of machining swarf and debris before being blown dry and prepared for final assembly. Assembly takes place in a dedicated area kept specifically for the purpose. Valves will be carefully refitted using new valve stem seals.
Cams, Rockers and Lifters
In cylinder heads with an Overhead Camshaft arrangement these parts can all be refitted and the valve clearances set if required. We offer a full valve setting service and can re-shim the valve tappet clearances if required. On cylinder heads containing hydraulic type tappets these will be drained, cleaned and re-set to allow full closure of the valves on start up. We also offer a repair service for other types of valve operating systems including rocker re-bushing and honing etc.
Other Services
For cylinder heads that are found to have any additional problems we can also offer the following services.
Line Boring – For the repair of broken cam caps and damaged camshaft housings Valve seat
Thread repairs – wire insert and time-sert available in a selection of sizes
Alloy welding – for head sealing faces damaged by erosion or for repairing some cracks.