Wrench – Engine / Cylinder Head Assembly Guide

This is a complete guide to both building and installing a cylinder head for your engine, starting from just an empty cylinder head casting, and finishing with installing a fully functioning cylinder head onto your engine block.

Engine / Cylinder Head Assembly

Valve Assembly

This section of the guide will teach you in complete how to assemble all 16 of the intake and exhaust valves that will later be operated by your camshafts.

Valve Insertion
Parts Required:
1x cylinder head casting
8x intake valve
8x exhaust valve

The first step in assembling the valves on your cylinder head is to insert the valves themselves into the cylinder head’s valve seats. To do this you are first going to want to flip your cylinder head upside down so that the valve seats are visible from above. This is what the underside of the cylinder head looks like.

Now, insert the valves into their corresponding holes cut into the valve seats, all 8 of the intake valves will be on one side of the cylinder head and all 8 of the exhaust valves will be on the other side of the cylinder head to allow them to be operated by their corresponding camshafts.

Valve Body Assembly
Parts Required:
16x valve seal
16x valve spring
16x valve retainer
16x hydraulic lash adjuster

Now that all of the valves have been inserted into the cylinder head you are going to need to flip the cylinder head back over so that it is upright and you can see down into the valve chambers as shown.

The first step to assembling the valve bodies is to insert valve seals at the bottom of each valve chamber, these parts are very small so I have included an image below to show their location. You should put one valve seal in each valve chamber.

The next step in assembling the valve bodies is to insert the valve springs into each valve chamber, I have shown the location of 2 of the 16 valve springs in the picture to demonstrate what I mean.

Now it is time to insert the valve retainers into each valve cylinder, I have shown the location of 2 of the 16 valve retainers in the picture to demonstrate what I mean.

Finally, to complete the assembly of your valve bodies it is time to insert the hydraulic lash adjusters into each valve cylinder, I have shown the location of 2 of the 16 hydraulic lash adjusters in the picture to demonstrate what I mean.

Congratulations. You have now finished assembling your valve bodies.

Camshaft Installation

This next section of the cylinder head assembly guide will teach you how to install the camshafts into the cylinder head, this will also involve the fitting of seals and the CAS, or cam angle sensor.

Camshaft Insertion
Parts Required:
1x intake cam
1x exhaust cam

The first step in installing camshafts into your new cylinder head is to appropriately seat them over their corresponding valves that you built in the previous section This is really simple to do, fit the intake cam over the top of the intake valves, and the exhaust cam over the top of the exhaust valves.

Exhaust Camshaft Retainment
Parts Required:
1x cam cap (exhaust 1)
1x cam cap (exhaust 2)
1x cam cap (exhaust 3)
1x cam cap (exhaust 4)
1x cam cap (exhaust 5)
10x cam cap bolt
1x camshaft seal

Now that both of your camshafts have been seated appropriately inside of the cylinder head it is time to retain them in place so that they can rotate to operate the valves, to do this you are going to install 5 caps per camshaft, and a seal under the first cap of each camshaft. Beginning with the exhaust camshaft, first place all 5 exhaust cam caps over the top of the camshaft, with cap 1 being at the front, and cap 5 being closest to the back. In my image the front of the cylinder head is facing to the left.

The next step is to seal the end of the camshaft assembly by inserting your camshaft seal into cam cap 1 as shown. The rubber seal should fit between the camshaft and the camshaft cap.

The final stage in retaining your exhaust camshaft is to appropriately torque the bolts holding the cam caps to the cylinder head. To do this, torque each bolt to 12nm following the order shown in the picture.

Intake Camshaft Retainment
Parts Required:
1x cam cap (intake 1)
1x cam cap (intake 2)
1x cam cap (intake 3)
1x cam cap (intake 4)
1x cam cap (intake 5)
10x cam cap bolt
1x camshaft seal

Now that your exhaust camshaft has been properly mounted to the cylinder head it is time to do the same with the intake camshaft. Just like with the exhaust camshaft, you are first going to place all 5 intake cam caps over the top of the camshaft, with cap 1 being at the front, and cap 5 being closest to the back. In my image the front of the cylinder head is facing to the left.

The next step is to seal the end of the camshaft assembly by inserting your camshaft seal into cam cap 1 as shown. The rubber seal should fit between the camshaft and the camshaft cap.

The final stage in retaining your intake camshaft is to appropriately torque the bolts holding the cam caps to the cylinder head. To do this, torque each bolt to 12nm following the order shown in the picture.

Cam Angle Sensor Installation
Parts Required:
1x cam angle sensor
1x cas cap
1x cas adjuster bolt
2x cas cap bolt

Now that your camshafts are both fitted to the cylinder head it is time to install the cam angle sensor onto the rear end of the exhaust camshaft. The first step in doing this is to actually fit the cam angle sensor into the rear opening of the exhaust camshaft as shown in the picture.

The next step is to fit the cas cap over the top of the cam angle sensor to hold it in place and to torque both of the cas cap bolts to 15nm.

The final step in fitting the cam angle sensor to the cylinder head is to insert the cas adjuster bolt into the right hand side of the cam angle sensor’s curved face and torque to 15nm.

Ignition and Temp Sensing

This section of my guide will run you through the process of installing spark plugs into the cylinder head and fitting the coolant temp sensor. These are both extremely straightforward processes that should not take the user any longer than 5 minutes to complete.

Spark Plug Installation
Parts Required:
4x spark plug

The process of installing spark plugs into your cylinder head is very straightforward, there are 4 empty tubes on the cylinder head that are located between the two camshafts, these are where you will be fitting your spark plugs. Begin by inserting your spark plugs into these holes.

Now it is time to torque the spark plugs to 18nm, to do this you will need to fit the extended socket onto the ratchette and set the torque limiter to 18nm. For desktop users fitting the extended socket is done by pressing the “Y” key.

Once all 4 spark plugs are torqued to 18nm you are done and the spark plugs have been installed into the cylinder head.

Coolant Temp Sensor
Parts Required:
1x coolant temp sensor
1x m8 flange nut
1x bolt: m8 x 15mm

Fitting the coolant temp sensor to the cylinder head is an extremely fast process, first begin by fitting the coolant temp sensor over the large circular hole in the back of the cylinder head.

Lastly, fit the m8 x 15mm bolt in the top left of the sensor and the flange nut in the bottom right and toque both to 20nm.

Cam Gears, Thermostat, Valve Cover and Electrical Inputs

This section of my guide will teach the user how to fit the cam gears, mount the cylinder head to the engine block, assemble the valve cover, and how to install the coil pack and plug wires required to complete the assembly of your cylinder head.

Cylinder Head Mounting
Parts Required:
10x head bolt

Now, it is time to mount the cylinder head to the engine block, to do this simply install the head bolts in the marked locations, torquing to 79nm from the centre bolts outwards.

Thermostat Installation
Parts Required:
1x thermostat
1x thermostat neck
2x bolt: m8 x 15mm

Next you are going to want to mount your thermostat to your cylinder head, to do this simply place the thermostat neck against the front of the cylinder head just below the camshafts in a central position and insert the two bolts in the guide holes either side of the necks base. Torque both of these bolts to 20nm and insert the thermostat into the open end of the neck as shown.

Cam Gear Installation
Parts Required:
1x engine timing plate
6x timing plate bolt
2x cam gear
2x bolt: M10 1.25 x 35mm
1x cam gear locking tool

The process of fitting the cam gears to the end of each camshaft is fairly straightforward. Begin by installing the engine timing plate, this plate is a vital component that helps you to time your engine properly. To do this simply place the timing plate underneath the ends of both camshafts on the front of the cylinder head and torque all 6 of the timing plate bolts to 10 nm.

Now it is time to fit the actual cam gears, the first step in doing this is fitting the cam gears to the end of each camshaft at the front end of the cylinder head as shown in the picture below.

Now you are going to want to fit the cam gear locking tool between the two cam gears to prevent the camshafts from rotating when you tighten the retaining bolts in the next step.

Finally, torque both bolts to 55nm.

Valve Cover Assembly
Parts Required:
1x valve cover
1x valve cover gasket
1x PCV valve
1x oil fill cap
1x coil pack
2x bolt: M8 x 15mm

The next stage in assembling your cylinder head is to assemble your valve cover, begin by turning your valve cover upside down and fitting the valve cover gasket to the underside of it.

Next you are going to fit your PCV valve and oil fill cap on top of the valve cover, the oil fill cap screws into the larger of the two marked holes, and the PCV valve fits in the smaller of the two.

Lastly, it’s time to fit the coil pack onto the valve cover, begin by flipping the valve cover up-side down again and placing the coil pack so that it occupies the space to the left of the semi-circular shaped hole on the rear end of the valve cover. Then insert the two M8 x 15mm bolts either side of the coil pack body and torque both bolts to 20nm.

Fitting the Valve Cover

It is worth noting that this part of the guide assumes that you already know how to assemble all of the timing components for the engine and have already done this prior to these last few steps, as this guide is to assemble and fit the cylinder head I will not be covering the engine timing assembly, so to not make this guide over-convoluted, however, I plan to cover this in another guide at some point. If you have not yet assembled the engine timing you should do this now before continuing with the final steps of this guide.

Valve Cover Retainment
Parts Required:
11x valve cover bolt

Now it is time to fit the valve cover to the cylinder head, doing this is a very simple process, just fit the valve cover on top of the cylinder head ensuring that the coil pack is to the rear of the valve cover and that the oil filler cap is near the front. Then torque all of the valve cover bolts to 7.5nm in the order shown.

Plug Wire Insertion
Parts Required:
1x plug wire (cyl 1)
1x plug wire (cyl 2)
1x plug wire (cyl 3)
1x plug wire (cyl 4)

Lastly, it is time to fit the plug wires to connect the spark plugs to the coil pack. This is the simplest part of assembling a functioning cylinder head. To do this simply place the plug wires so that the thick rubber probe fits into the holes above their corresponding cylinder and the hollow rubber cap fits over a hollow cylinder on the coil pack.

Congratulations, you have now completed the assembly of your cylinder head, just fill the engine up with oil and you are good to go.


Written by: RumHam


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