Cylinder head repair presents a way to save on costs, especially when on a tight budget. There are also times when repair is recommended over replacement- or the only option. Read this section to find out how to carry out cylinder head repairs. I will also be explaining the cylinder head repair cost while taking into consideration the different types of the component.
What is Cylinder Head Repair?
The cylinder head on your car engine helps cover the combustion chamber, helping to ensure proper combustion and compression pressures. It also houses components that the engine requires to function. When damaged, therefore, the engine is affected. Cylinder head repair involves several processes; all aimed at fixing problems that cause the engine to perform poorly. They include:
- Cylinder head machining to remove warps
- Cylinder head welding, sealing, or pinking to fix cracks
- Cylinder head rebuild to replace worn or damaged components such as valve seals, valve sets, and valve guide
- Cylinder head cleaning to remove carbon build up
- Cylinder head gasket Repair
Warped Cylinder Head Repair
During machining, also called cylinder head skimming, cylinder head decking, or cylinder head re-facing, a milling machine is used to remove some material from the mating surface. This is the flat surface that facing the cylinder block and which is separated from the block by a sealing gasket. It’s also called the deck.
Cylinder head machining serves to remove unevenness from the surface, thereby retaining the manufacture specifications. A perfectly flat cylinder head deck means air tight joint and well-sealed cylinders.
To machine warps, you need a milling machine. This cylinder head repair tool may be out of reach of many car owners. As a result, it’s usually necessary to have it done by a professional engine rebuilder or at a cylinder head machine shop.
It’s important to understand that milling removes some material. That means a reduction in the thickness of the assembly that could affect the compression ratio. As a result, cylinder head specialists recommend using a thicker gasket after the process. There’s also a limit to the number of times that you can reface the head.
Cracked Cylinder Head Repair
Cylinder head crack repair mostly involves sealing, welding, or pinning the cracks. The helps stop the oil or coolant leaks and allows the head to serve for a few more miles. You can also seal voids in the casting. Most of the time, though, cracks are welded or pinned.
Cracked aluminum cylinder head repair by welding includes using tungsten inert gas. Cast iron head cracks are commonly fixed by flame spray welding. Welding helps remove cracks, but requires special tools to perform.
The most popular method to fix cracks today is pinning. This technique works by drilling tiny holes along the crack. Pins are then inserted and hammered in to provide a seal and produce an even surface. In all these instances, it’s good to note that large cracks mean a head that should be changed.
Cylinder Head Rebuilding
During cylinder head reconditioning or rebuilding, damaged parts are either machined or changed. These include valves, valve seats, valve seals, valve springs, and other parts that the head houses. Most of the time, this repair procedure requires a professional to carry out.
A cylinder head rebuilder will change worn or damaged parts safely. They will also carry out complex machining of the deck. The ports too, and improve the flow of gases through the passages. This process commonly called cylinder head porting.
Cylinder Head Cleaning
Removing carbon from a cylinder head helps makes inspecting the assembly easier. It also helps to remove build up so the passageways and ports can provide an efficient flow of gases.
When doing the cleaning, it’s important that you use the right cleaner for the head material. Aluminum cylinder heads are easily damaged by corrosive chemicals. It’s also important to avoid using abrasive pads, and instead employ mild ones such as wire brush to remove carbon and dirt.
Cylinder Head Gasket Repair
In addition to a cylinder head overhaul, the gasket also requires repairing. This ensures the best result. That’s because some issues with the cylinder head result from damage to this component. A blown cylinder head gasket, for example, causes the head assembly to warp.
Gasket repair uses various methods to correct problems. It can be sealing or resurfacing. Sealing corrects holes in the gasket and helps to restore its sealing function. Re-facing fixes problems that result from a distorted gasket, such as leaks.
Cylinder Head Repair Cost
The cost for cylinder head repair varies greatly. One of the reasons for that is the different types of the head across vehicles. Their number too, with some vehicles using two pieces. The cost is also determined by the type of problem. Different problems require different process to diagnose and fix.
Generally, many cylinder head repair shops charge around $200 to fix the part. This is an estimate, though. Depending on your type of car, you may have to pay a higher amount, sometimes up to $500. The cost is also higher is your car uses a V type of engine or a Boxer engine.
With that in mind, it’s important to consider fixing the head yourself, especially if the damage is minimal. Most importantly, choose DIY repair if the process does not require specialized cylinder head repair tools such as a milling machine.
Some repairs, such as changing a few of the cylinder head assembly parts, are easy to carry out. In most cases, though, many problems require a mechanic or engine rebuilder. These include those that require decking or porting. Cylinder head porting refers to the process of grounding ports using special tools.
The amount that you pay for professional cylinder head services should always be less than that of replacement. If higher, a more logical choice would be replacement. It’s good to note that some issues cannot be repaired. These include serious warps or if the head is too thin to be ground. Extended cracks too, or an excessively worn assembly.
How to Maintain a Cylinder Head
Cylinder head problems will eventually develop over time. However, some problems result from wrong actions by vehicle owners. Others are caused by delayed car maintenance procedures, especially those that involve engine parts. Below are tiles to make the cylinder head on a car engine last longer.
- Ensure regular engine service. A poorly maintained engine is likely to overheat and cause serious cylinder head problems such as warping or cracks.
- Always service the cylinder head on time. Machine warps and fix cracks before they get out of control. That applies to those considering cylinder head repair instead of replacement.
- Always ensure the good condition of the cylinder head gasket. A blown head gasket can cause severe warping. Gasket damage is also one of the reasons or oil leaking from cylinder head assemblies.
- Never pour water into a hot radiator. The temperature fluctuation would cause the cylinder head to either warp or crack. Instead, allow the radiator to cool first.
- Always avoid using an overheated engine. The high temperatures will warp or crack the head. If the engine has overheated, consider pulling up to allow it to cool. Have it checked, too, by a qualified technician for issues.
- Ensure a functional cooling system at all times. This includes the radiator, radiator cooling fan, coolant hoses, and associated parts. A malfunctioning cooling system will quickly cause overheating and lead to cylinder head issues.
- Always ensure even clamping forces on the cylinder head. Incorrect cylinder head bolt torque is one of the reasons for that. Always use the right torque setting and bolt sequence when removing or installing the head.
The cost for cylinder head repair can be high. Some engines also use two cylinder heads, which increases the expenses. When faced with a damaged head, the choice is usually repair or replacement. Most of the time, changing the head is the only option. The following chapter details the steps to change the cylinder head without expert knowledge.