How to Install Head Bolts

If you have never installed head bolts, it is best to do your homework and arm yourself with the bolt torque and tightening order specs of the engine you're working on. Proper bolt lubrication, cleaning, and deburring, along with aluminum heads and washer placement, all help to make the engine work properly upon completion. There is no such thing as a quick-and-dirty job when it comes to head bolt installation: do it right or you'll have a problem on your hands.

Procedure:
1. Inspect each bolt to assure clean and undamaged threads. Use a wire brush to clear any foreign matter off the threads. Use the service manual to check proper bolt length for each location. If the head has been resurfaced, bolts may be slightly too long and bottom out before exerting the proper downward force on the head. In this case, use hardened steel washers to make up for lost head height.
2. Run a bottoming tap down each bolt hole to clear out any debris. Apply motor oil to all bolt threads and to the bottom of the bolt head. If the head is aluminum, use manufacturer-recommended hardened steel washers under each bolt head, chamfered-side up, lubricated. If the head has been resurfaced, you will have to use thicker washers to make up for lost head height to keep bolts from bottoming out. Make sure all surfaces on the head, washers and bolts are clean and burr-free.
3. Drop each bolt into its respective location and finger tighten. Use the service manual for bolt-tightening sequence. Use the beam-deflector torque wrench to tighten all bolts in 3 to 5 steps. The first step tightens all bolts in sequence to a percentage of full torque. Each subsequent step tightens all bolts in sequence to progressively higher torque specs until the final step sets the bolts to the rated final torque. Guesswork can warp the head or cause leakage and overheating.
4. Re-check torque on all bolts. If you missed one, this step will find it. Bolts are made to stretch somewhat, so the final torque check assures proper clamp force on the head.