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 Cylinder Head Reconditioning

Our fully equipped cylinder head machining shops have the ability to machine cylinder heads of all shapes and sizes from small single cylinder alloy heads to the largest cast iron diesel heads seen in high speed high horsepower off higway applications. Our cylinder head reconditioning service includes, valve guide fitting and reaming, valve seat insert replacment and valve seat machining, valve refacing, cylinder head milling and fire ring  recess re-machining. Cylinder head pressure testing, final rinsing and valve train assembly all make up part of the reconditioning process. All machining is completed to O.E.M tolerances and specifications. 

Connecting Rod Inspection

The inspection process includes non-destructive magnetic particle crack testing, gudgeon bush to pin clearance checks and proof testing, con rod bearing tunnel size checking, rod alignment (bend & twist) and comparable length.

Con Rod Reconditioning

When required the gudgeon bush can be replaced using techniques as specified by the Original Equipment Manfacturer (O.E.M) including induction heating and cryogenic freezing. Gudgeon bush broaching, pin boring and honing can also be completed ensuring correct gudgeon pin to bush clearances.Con rod bearing tunnel polishing, close and honing and close and grinding can also be carried out ensuring the correct bearing shell contact and crush are achieved. Re-checking of the rod alignment and a final quality inspection takes place before the item is returned to the customer. All connecting rod servicing is carried out to exacting tolerances, as per the O.E.M specification and procedures.

Crankshaft Inspection / Crankshaft Crack testing

Hissen provide a cost effective crankshaft reconditioning service. When a crankshaft arrives at workshop a full survey report is completed. Non destructive magnetic particle crack testing, Rockwell hardness testing, journal and radius measurements are all recorded to establish the components viability for reuse. 
All crankshafts have gallery plugs removed and are chemically cleaned to ensure all oil feed gallerries are free from oil sludging and frogien material contimination. A full survey report is completed on every crankshaft. The inspection process includes, non destructive magnetic particle crack testing, Rockwell hardness testing, crankshaft bend checking (T.I.R. Total Indicator Runout). All journal radii are examined and all journals are checked for sizing, taper and ovality, finally the shaft is de-magnetised.

Crankshaft Grinding / Polishing and Final Inspection

Crankshaft up to 4000mm in length with a 300mm stroke can be ground to the next available undersize. All journal machining is carried out as per the manufacturers exacting tolerances, fillet radii are dressed and the crankshaft is micro polished. On completion of the machining process a closing report with specifications and finished sizes can be supplied. Note machined coolant tracks in grinding wheel ensuring thrust face and radius overheating during the machining process is eliminated.

Camshaft Grinding

All camshafts are subjected to a full survey inspection. Non destructive magnetic particle crack testing, camshaft bend (T.I.R), gear and thrust areas, bearing journals, camshaft lobes, injector lift lobes and eccentrics are all scrutinised and check against Original Equipment Manufacturers (O.E.M) specifications. When required camshafts are straightened, bearing journals polished and camfollower lobes are redressed.

Valve Spindle Reconditioning

We also can recondition the valve spindle as clients’ request, and Application of Vacuum fusion welding and hardening treatment for high performance Exhaust valve of Diesel Engine. Exhaust valve is one of the most important moving components of diesel engines. The quality of the alloy layer of its sealing surface determines the service life of exhaust valve. A new technology, vacuum fusion welding and hardening process is developed by Shanghai Golston. The actual application shows obviously effect. Without change in any material, the hardness of alloy layer can reach 60.6HRC and metallographic structure can reach Grade 12.
Service including as below,
Austenite Stainless Exhaust Valve, higher nickel content alloy Exhaust valve
Valve facet reconditioning
Valve bottom side reconditioning
Valve Chrome-plated and dimensions restore
Change of valve wing