Crucial Head Bolt Installation Tips Every Engine Specialist Must Know

The essential fasteners for any engine are head bolts. Therefore, you must ensure all head bolts remain lubricated and in excellent condition to prevent overloading. If you are an engine specialist or technician, continue reading for essential tips to seal up your engine.

First, always ensure all your engine head bolts are in perfect working condition with untampered threads. Damaged and dirty threads result in inaccurate torque readings, as well as reduce the bolt's clamping force. Therefore, you must inspect, wire brush and replace the worn-out or deformed bolt threads. Additionally, when you can't easily thread a bolt into a hole using your fingers, that implies a problem.

Dirty and damaged hole threads in your engine block can also be responsible for reduced clamping force. To fix this, you need to consider running a bottoming tap on every block's bolt hole. Chamfer tops of each hole to prevent upper threads from pulling above the engine's block deck after tightening. Additionally, don't forget to clean up each threaded hole of any debris.

You should also check your head bolt's length. Regularly ensure you have the right measurements for your bolts, as well as for every hole position. You may require longer or shorter bolts for different holes. Having shorter bolts means risking pulling threads from the block's holes since they engage only a few threads. Always scale and compare bolts to identify any signs of stretching. Consequently, replace any stretched-out bolts immediately as they may be weak or unable to hold torque efficiently.  

Resurfacing your engine's cylinder head may lower its standard height. Hence, it may help if you check the length of the bolts to prevent them from bottoming out in the block's blind holes. Bottomed-out bolts exert less or no clamping force to the head, resulting in leaking gaskets. For a milled head with several bolts almost bottoming out, correct this issue with hardened steel washers beneath the locks. 

Always use the recommended torque wrench for tightening standard-type head bolts. Do this in 3-5 incremental steps while observing the required manufacturer's sequence and torque specifications. You should also consider tightening the bolts gradually to achieve an even clamping force as well as decrease head distortion. Always double check your final torque readings on each head bolt for precision.


These are the five crucial head bolt installation tips you must keep handy while sealing up your engine. You can reach out to your local auto shop to learn more about using ARP head bolts.