An internal combustion engine – the type of engine which can be found in most vehicles today – comes equipped with a cylinder block that contains all of the major components where the combustion process takes place, and contains a number of cylinders. Atop the block is the cylinder head, which seals all of the cylinders to keep them safe. More importantly, the cylinder head houses passages for the combination of fuel and air to facilitate combustion in an engine.
The cylinder head also features exhaust valves, which remove any unwanted fumes produced by engine combustion. All of this work wears on the cylinder head over time, and eventually it will need to be reconditioned in order for you to enjoy optimal engine performance in your vehicle. Below are the steps an experienced mechanic will take to perform reconditioning on your vehicle’s cylinder heads.
1. Stripping the Cylinder Head
Internal combustion engines are complex machines that are assembled over long periods of precision engineering. Reconditioning the cylinder heads begins with the careful stripping of the head to prevent any damage to other parts of the engine.
2. Cleaning the Cylinder Head
After the stripping process is complete, it must be followed up by cleaning to remove any dirt or grime which has accumulated over time. Any knowledgeable reconditioning service provider will know to clean the head with a waterjet and soap. Thereafter, it should be dried using dry, compressed air.
3. Hydraulic Testing
In today’s engineering landscape, most manufacturers will use two techniques when crafting cylinder heads: they either fit them with aluminium screw plugs, or glue them together using Loctite. Both of these techniques must be tested hydraulically to identify any leaks in the cylinder head. Hydraulic testing involves the following steps:
- Loctite glue heads are removed, refurbished, re-glued and clenched together using a specialised machine. This restores the cylinder head bond and ensures that no leaks occur.
- Cylinder heads sealed using aluminium screw plugs are re-drilled according to the manufacturer’s guidelines. Air testing then follows at a pressure of around six kilogrammes per centimetre squared. If any leakage persists at the drilling points, the hydraulic test is carried out again until it stops leaking.
4. Restoring the Firing Place
The firing place refers to the point of ignition of the air and fuel combination. For perfect fuel ignition, the fuel firing place needs to be refaced. This begins with scrubbing the region with a scratch brush to remove rust, dirt and paint residue. The technician then uses a set of gauges to examine the flatness of the firing place. If the region has bumps and marks, the technician must grind it down to ensure that it is as flat as required.
Looking for Diesel & Petrol Cylinder Head Reconditioning Services?
At the Welham Group, we are experts in reconditioning cylinder heads for a wide range of vehicles and engine types. Whether you require cylinder head reconditioning for your diesel or petrol vehicle, you can count on our experienced mechanics to get the job done right. Our comprehensive service includes pressure testing, crack testing, surface grinding, valve guide replacement, seat recutting, lapping-in of valves, new seat inset fitting and head conversion for unleaded use. For more information, get in touch.