Part 1. Preparation and safety
Objective
- Install the heads onto the block.
Personal safety
Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:
- Work clothing - such as coveralls and steel-capped footwear
- Eye protection - such as safety glasses and face masks
- Ear protection - such as earmuffs and earplugs
- Hand protection - such as rubber gloves and barrier cream
- Respiratory equipment - such as face masks and valved respirators
If you are not certain what is appropriate or required, ask your supervisor.
Safety check
- Make sure that you understand and observe all legislative and personal safety procedures when carrying out the following tasks. If you are unsure of what these are, ask your supervisor.
Points to note
- Lubricate under the heads and on the threads of the bolts.
- Identify the correct orientation of the gaskets from the markings.
- Use non-hardening sealer on the threads of the head bolts.
Part 2: Step-by-step instruction
- Clean and lubricate
Clean the block deck surface and the decks of the heads with some lacquer thinner.
Retrieve all of the head bolts from their storage bin to be prepared. If the head bolts go into holes that have solid bottoms to them, you only need to put engine oil on the threads and on the undersides of the heads of the bolts themselves. If any of the head bolts go into holes that extend into the water jacket, it is essential to put some non-hardening sealer on to the threads of the bolts to keep the coolant from leaking past the threads. They will also need some oil or assembly lubricant on the underside of the bolt heads.
- Install head gaskets
Look for any 'this side up' or 'front' labels on the head gaskets. If there are no labels, it shouldn't matter which side goes up. Just double check that for every hole in the block or heads, there's a corresponding hole in the gasket.
Composition gaskets don't need any sealant on either side but a metal shim gasket needs an even coat of a high-tack gasket sealer sprayed on both sides .
- Install head
Gently lay the head on the alignment dowels of the block and start threading in the bolts. If you have a few different sizes of head bolts make sure that the right bolts go in the right places. Also, install the safety pin in the stand to keep the weight of one head from spinning the engine upside down before it's balanced with the other head.
- Torque head bolts
Go through each bolt on both heads and make them hand tight with a wrench. Torque in three increments, resetting the wrench and increasing by a third each time.
Cylinder heads require that you torque the bolts in a certain sequence. Most heads have a similar sequence to this engine. Start from somewhere in the center and tighten in a spiral pattern towards the outer bolts. If your engine has it's own particular pattern, follow the instructions in the repair manual.
Sometimes it's hard to keep track of which bolts have been torqued and which haven't. Make a note of how many total bolts you have, and count as you go. When you get to what you know is the last bolt in the sequence and the count is one short, then you'll know that you missed one. You should double-check regardless, especially when you get to the final torque specification.
