Cylinder Head Resurface or Skimming

Why should you have your cylinder head skimmed?

We undertake in resurfacing (skimming) both aluminium and cast iron cylinder heads, from cars, vans, tractors, plant machinery, boats and many more, to a high standard, removing the equivalent to less than a hair strand thickness to return the flat surface needed.


It is advisable to have your head skimmed after a head gasket failure. When your vehicle has suffered with a blown head gasket, the cylinder head can become distorted and leave marks from where the gasket was blowing, if the head is replaced after distortion isn't corrected, it is highly likely that the head gasket may blow again. 

To prevent this from happening, we at Barnes Auto Engineering can resurface (skim) your head creating a perfectly flat surface for resealing the head to the block.

It is also a good idea to have the cylinder head skimmed when it has been removed after a cam belt failure. If there has been the slightest of distortion over time, if it is off, getting it skimmed won't do it any harm, it may save you time and money in the future if any slight distortion that wasn't repaired turns into a blown head gasket. We can't see distortion with our eyes, thinking it is perfectly straight may be a costly mistake. 

Corrosion, which can be caused by using incorrect usage of coolants in aluminium cylinder head which appears around the coolant passages and/or where a head gasket has blown and coolant has escaped between the gasket for a long time period. Corrosion is more common in old cast iron cylinder heads, which can cause small porous areas around the coolant passages. Rust, a product of air, water and iron can form over cast iron cylinder heads when they have been stored out of the vehicle for future use. Corrosion and porosity can be tested for before we resurface your cylinder head by pressure testing.

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Obvious Signs of Head Gasket Failure


  • Constant overheating, if your vehicle has overheated too many times from lack of water/coolant, blocked radiators etc, it can cause your head gasket to blow, which in turn causes your engine to overheat, this overheating and cooling, when the engine is switched off causes the cylinder head to distort. 

  • White, sweet smelling smoke from your exhaust is a sign that your coolant has escaped past the head gasket into your cylinder bore and is being turned into steam by the combustion process. Blue smoke is when the oil has escaped instead. Coolant and oil should not be present in your cylinder bore. 

  • Oil in water or visa versa is when you find that milky sludge on the underside of the oil filler cap. This isn't concrete proof, but its a good indication that there is something wrong and needs attention. Driving with coolant mixed in with the oil could ruin areas of the engine that need to be kept lubricated.

  • We may experience a noticeable loss of power, this is where fuel and air, which is what should be inside the cylinder bore, escapes, causing the compression to drop, this may cause the vehicle to sound like the engine is running 'rough'.In extreme cases it can cause a misfire, where your engine feels juddery or lumpy.

  • Another sign of head gasket failure is excessive pressure in the cooling system and external coolant and oil leaks may be noticed around the engine, it is always good practise to stop any fluid leaks as soon as you notice them, e.g if coolant levels are left to drop below minimum, then read the first one again.

 

©2016 - 2020 by Barnes Auto Engineering.

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