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Do-It-Yourself Projects
Engine Assembly, Part 5: Installing the Cylinder Heads
By Wayne Scraba/autoMedia.com
Printable version
Degree of DifficultyModerate
Moderate
Estimated Time240 minutes
240 minutes
Installing the Head Gasket
Clean the cylinder block deck surface. Typically, we spray a small amount of brake cleaner on a lint-free shop towel and wipe the deck clean. Ensure the cylinder head dowels are in place on the deck surface. Following the head gasket manufacturer’s specifications, install the gasket. Some composition gaskets such as the Fel Pro Permatorque MLS shown in the accompanying photos do not require any special sealers and, as the name suggests, they do not require a hot re-torque. Some gaskets mandate a small bead of silicone be applied around the water ports in the deck surface. Other gaskets require sealers to function properly. In any case, the gasket can now be placed over the head dowels on the deck. Most gaskets are designed to either fit one way or with the part numbers facing up (toward you).
 
Installing the Cylinder Heads
Clean the cylinder head deck surface using the same process as used on the block deck surface. Rotate the engine on the engine stand so that the deck you’re working on is parallel to the floor. Carefully place the cylinder head on the deck, over the head gasket. Be sure the heads fully engage the alignment dowels and are flush with head gasket.
 
Before the cylinder head bolts are installed, be certain you have the right mix and length of fasteners. With the cylinder head installed, hand thread each head bolt into the block deck to determine the length is correct. In our case, we used ARP head bolts with hardened washers (which have an effect upon the installed length). Our big block example uses 16 head bolts in three different lengths per cylinder head.
 
Once the number of bolts and length is determined, you can install the fasteners. We always wipe the fasteners clean and follow the manufacturer’s installation instructions. Some engines (where the head bolt enters a water jacket) mandate a thread sealant on the bolts. Others such as our sample engine have blind holes in the deck. That means the bolts do not enter the water jacket and as a result, sealants are not required. Companies such as ARP provide a special assembly lube with their head bolts. Apply the assembly lube to the bolt threads as well as the area between the head bolt and the head bolt washer. You’ll note the head bolt washers are machined on the ID. The machined side faces the hex on the head bolt.
 
Torque the Fasteners
Head bolts (or studs) should be torqued in three steps of equal value. They should also be torqued in the right sequence. The manufacturer of the engine you’re working on will definitely have a torque specification along with a sequence of which fasteners to torque in which order. Generally speaking, the sequence begins in the center of the engine and works outward.
 
What we try to do is to split the specified torque into three. For example (and this is only an example), if the engine manufacturer specifies the torque as 90 foot-pounds, we’d begin by setting the torque wrench at 30 foot-pounds and then go through the torque sequence. Next, we’d adjust the torque wrench to 60 foot-pounds and go through the torque sequence. Finally, we’d set the torque wrench to 90 foot-pounds and re-torque once more, following the sequence. Repeat the entire process on the second cylinder head and you’re done.
 
Install Rocker Arm Stands
Conventional stud mount rocker arms are installed after the lifters are dropped into the lifter bore. Next, a pushrod is set in place and then the rocker arm can be installed on the rocker stud. It’s a simple process, and we’ll show more of it in the final segment.
 
A shaft rocker, such as the Jesel setup shown in our build is a little different. It functions by way of a small shaft bolted to a stand. These stands are held in place by two torx-head capscrews along with a special link stand. First the link stand is set in place, followed by the actual rocker stand. Typically, the rocker stand for the intake differs from the one on the exhaust side. You have to be careful during the installation to ensure the right stand goes on the right rocker boss on the cylinder head.
 
On an engine such as the big block Chevrolet shown in the accompanying photos, two different length torx capscrews are used. You should use the longest bolt possible, but be sure to inspect the ports. In some cases, if a long capscrew is used, it will protrude through an intake port. If it does, switch to the shorter (supplied) torx fasteners. On cylinder heads where the capscrew (or the rocker arm stud) enters the intake port, you’ll have to use some form of thread sealant on the fastener threads.
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