Cylinder Head Resurfacing Cost [4 to 8 cylinders]
Car engine pistons move quickly inside their cylinders over time, the resulting friction can wear down the cylinders, leading to engine failure.
Luckily, periodic resurfacing of the heads can prevent this disaster while keeping your engine near its proper performance standards. Cylinder head resurfacing costs around $500 for most engine builds, though it can reach as high as $700.
Either way, resurfacing the heads is much cheaper than replacing the cylinders themselves while still providing the same level of maintenance.
Once the engine misfires, there is not much you can do to save on cost, but proper maintenance can keep your maintenance costs low. By reading further, you will learn the telltale signs that your cylinders are wearing out so you can resurface them as soon as possible.
How Much Does Resurfacing a Cylinder Head Cost?
Cylinder heads form the top of your car’s engine. Flushed with the top of the engine block, they seal the combustion chambers, allowing the engine to burn fuel into power.
The heads do this through valves that direct the flow of fuel and air. Over time and under extreme conditions, the cylinder heads can crack or wear down, producing symptoms similar to a cracked block or blown head gasket.
The traditional solution was to buy a new cylinder head, despite being more expensive than a blown head gasket. While nothing can help with a completely broken cylinder head, newer technologies allow you to rebuild the heads if they are just worn out.
Resurfacing restores or improves the finish of the cylinder heads and blocks. It can also change the deck height if needed.
Average Cylinder Head Resurfacing Cost
As the process requires no new parts, all professional cylinder head resurfacing jobs just charge for labor, which is typical $60 to $80 per hour for most U. S. machine shops.
Because your car may need all of its heads resurfaced and skimmed at the same time, the process can take a few hours. As a result, your final cost will be around $400 or more based on the number of cylinders your car has.
Though, some shops may charge different rates based on the material construction of your engine, which can be either aluminum, cast iron, or steel.
Some typical price points include
- 4-cylinder engines: $400 – $500
- 6-cylinder engines: $500 – $600
- 8-cylinder engines: $600 – $700
How to Resurface a Cylinder Head?
Luckily, resurfacing is one of the few car maintenances that can be done as a do-it-yourself (DIY) project). If your car uses small aluminum heads, the process is simple, and you may already have the tools to do it.
You still have to know what you are doing though because any mistake will ruin your vehicle. As a result, most people will need professional resurfacing to restore the performance of their cars.
Professional resurfacing is also required if you need special tools such as those required to mill steel and cast iron. One of the most common services offered by machine shops, your car may need professional cylinder head resurfacing to:
- Stop a head gasket leak
- Restore flatness or improve the surface finish
- Clean up welds or other repairs
- Increase compression ratio
- Align aftermarket intake manifolds
The Cylinder Head Resurfacing Process
Either as a DIY project or with professional machining, you resurface a cylinder head using the same quick, efficient, and proper way. There is no room for error here.
If the surface becomes too rough or too smooth, the head will not seal the cylinder properly, leading to leaks. There is no room for errors here either. You are removing metal, which you can never get back to start again.
As such, you want to make sure you check for the recommended specifications for your car’s engine before you begin.
It Starts with the Right Milling Machine
To achieve the specified smoothness, you need a milling tool with the right table feed rate and speed. Generally, this means you need a variable-speed or multi-speed milling table with an appropriate head.
That way, you can speed up or slow down the cutting head to dial in the proper smooth finish. Because of this, most professional machinists recommend using a two-bladed bit with a feed rate of about two inches per minute of 1,000 revolutions per minute (rpm).
They also recommend carbide or PCD bits for aluminum cylinders and carbide or CBN for cast iron. Once milled to the right specifications, you should clean the finished head to remove any excess dirt, oil, grease, or milling residue.
These contaminants can accelerate the wearing process and could lead to premature engine failure in the future.
Alternative Cylinder Head Resurfacing Methods
Milling down the head provides the most control over the resurfacing, letting you adjust the process according to your equipment and vehicle specifications.
While it is currently the industry preferred resurfacing method, it can leave the surface rough and dirty. A thorough chemical or thermal cleaning can remove the residue, but some shops employ other methods in an attempt to reduce the required labor and equipment costs.
The most common alternative method is hand sanding the surface. This method uses an abrasive pad affixed to an air drill or buffers to remove the residual metal and oils on the cylinder head, block, and manifold.
While quick and easy, it can remove metal, leaving a depression on the surface that cannot be easily sealed.
Belt sanding is a more traditional cylinder head resurfacing method. Many machine shops prefer it because you do not have to mount the heads to sand them.
However, belt sanding is no longer recommended as it is not as precise as grinding or milling. It is also completely dependent on the operator’s skills.
Therefore, most experts recommend reserving belt sanding for clean-up work or resurfacing hard-to-fixture components such as manifolds and timing covers.
Signs That Your Vehicle’s Cylinder Heads Require Resurfacing
Under most situations, car engine cylinder heads are very durable. You rarely have to worry about them as normal engine maintenance will keep them smooth and sealed.
Therefore, you should only resurface them when they get damaged. As such, knowing the telltale signs of damaged cylinder heads can go a long way.
Reasons for Cylinder Head Wear and Tear
As a cylinder head weakens, it starts producing the same symptoms as a worn gasket or a leaking block. This is because similar processes are at play. The most common of these issues include:
Overheating the engine can put excessive stress on its components. This stress can warp or crack the aluminum in the cylinder head.
Air trapped in the cooling system
The trapped air can produce hot spots These hot spots can boil the coolant, producing the same conditions as overheating
Failed water pump
a broken pump will not properly circulate the coolant through the engine, producing hot spots that can deform the metal.
Depending on how it broke, a broken thermostat can overheat the engine or make it run cold.
If too much coolant is lost, the engine will overheat.
Poor quality oil or coolant
Poor oil or coolant can make engines overheat faster than normal
Loose cylinder head bolts
the bolts holding the head to the cylinder can get loose, causing leaks
Worn Cylinder Head Symptoms
Minor cracks and degradation in cylinder heads are difficult to spot through just a visual inspection. Therefore, you need something more obvious to tell you when your car needs servicing.
Fortunately, worn-out and cracked heads do come with some very obvious signs, including the few common ones below.
Oil leaks always signify that something is wrong with your vehicle. Every component has oil running through it, including the cylinder heads. If a head or its seal cracks or breaks, the oil can will leak out of it.
Your car’s oil pressure light may even flash on as well. Either way, the oil should be visible near the cylinders or smoke coming out of the exhaust.
Along with oil, coolant can leak out of any cracks or holes in a cylinder head. The coolant loss can make your engine overheat.
If the leak is slow, you want to get to an auto repair shop as soon as possible. However, you should never drive your vehicle if you see a fast, visible leak.
Poor Engine Performance
Probably, your first noticeable indicator that something is wrong with your engine is a sudden decrease in engine power. The worn-out cylinder head will leak compressed air from the combustion chamber, reducing engine performance.
The engine can even misfire if the problem is severe enough, causing your car to stop working.
While rare, smoke can bellow out of any holes and cracks in the cylinder heads. The smoke, which is vaporized coolant or oil, is a clear sign that there is something wrong with the engine.
The reduced oil and coolant pressure can cause the engine to overheat, misfire, or worse.
Your engine’s cylinders encase the parts that move your vehicle. The cylinder heads cap these structures, directing the flow of air and fluids through the engine.
If these heads break or wear out, the engine can lose power or even misfire. Fortunately, you can quickly and cheaply resurface the heads to keep them working properly.