Engine Building Fundamentals: Head Installation
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Head Installation
03.19
| 00:00 | - Once we have all the pistons fitted to the block, the last part of the assembly process that we're going to deal with here involves fitting the cylinder head. |
| 00:10 | First though, there's little prep work required on the block. |
| 00:14 | We want to begin by making sure the crank shaft is rotated until the piston at number one cylinder is located at TDC. |
| 00:21 | This will ensure that we don't risk bending valves while the cams or valve train are being installed and timed. |
| 00:29 | The head gasket seal requires the mating surfaces of both the block and the cylinder head to be perfectly clean, so before installing the head gasket, I'll use a product such as Brakeclean or isopropyl alcohol and a clean rag to wipe down both surfaces and remove any oil or dirt. |
| 00:49 | If you're using a head stud kit, this is the time to install the head studs into the engine block. |
| 00:55 | Any fastener you install in a threaded hole should install smoothly by hand. |
| 01:00 | If you need to apply excessive force, then it may indicate the thread in the block, or perhaps the fastener is damaged. |
| 01:07 | In this case, you should stop and address the problem. |
| 01:10 | Studs don't need to be installed with a thread-locking compound and they also don't need to be tightened excessively. |
| 01:17 | All we need to do is screw the stud into the block until it bottoms out and is hand tight. |
| 01:23 | Now we can install the head gasket using the studs to guide the gasket into place. |
| 01:28 | It's always important to ensure that the orientation of the gasket is correct, and any oil galleries and water jacket transfer holes line up correctly. |
| 01:39 | The head gasket will typically locate over a couple of dowels in the block, and it's important to make sure it's in place and sitting flat on the engine block. |
| 01:49 | Now we can lower the head into place over the studs, ensuring that the head is lowered squarely onto the engine block. |
| 01:57 | Once it's correctly located over the dowels in the block, the washers and nuts can be installed and the head can be torqued into place. |
| 02:05 | If you're dealing with aftermarket head studs, this can get a little tricky as often, there'll be little information to go on other than the final torque setting that we need to use. |
| 02:16 | What we need to do is torque the head down in stages and torque the fasteners in the right order, so that the head is clamped down evenly and achieves the best seal possible. |
| 02:29 | If the stud manufacturer doesn't provide an order to torque the studs in, then I follow those used by the OE manufacturer, which might look something like this. |
| 02:39 | The torquing process will normally start in the middle of the head and then move gradually out towards each end. |
| 02:46 | If you're using factory head bolts, then you'll want to use the factory torque specifications and stages, but with aftermarket studs you may only have the final value to go off. |
| 02:57 | In this case, I'll torque the studs in three equal stages. |
| 03:01 | For example, if the final torque is 90 foot-pound, I'd torque all of the studs initially to 30 foot-pound followed by a second stage to 60 foot-pound and finally a third stage to 90 foot-pound. |
