Head Studs Vs Bolts: An Ultimate Guide

Every car engine experiences some kind of stress on a daily basis.

Especially for heavy-duty diesel engines like the Cummins, Powerstroke, and Duramax, you will find them somehow particularly vulnerable to external factors.

So to prevent your vehicle from being exposed to potential risks (for example, having broken wheel studs while driving), certain components like head bolts or head studs are what keep these engines from disintegrating, blowing the head gasket, or experiencing similar issues.

That is why it matters for you to grasp in depth the advantages and disadvantages of head studs vs bolts and know whether you should use the former or the latter.

Now, let’s wait no more but read on for further details!

When Should You Use Head Bolts?

Head Studs Vs Bolts

People typically use the bolt head to secure engine cylinder heads even when the cylinder wall gets damaged, which are usually in groups of two plus two.

As such, this element’s mission is to guarantee that cylinders are completely sealed, limiting pressure losses in the combustion chamber, and preventing any pressured burnt gasses from leaking to coolant conduits.

But how could they do so? Many may wonder.

The process can be easily understood as they apply an axial load that maintains a consistent contact pressure on the head gasket.

They must also avoid excessive loads to prevent cylinder deformation and subsequent engine breakdown.

As a result, their surface coatings’ friction coefficients should be specified and constant, as well as their mechanical strength must have a relatively small tolerance range.

When Should You Use Head Studs?

When Should You Use Head Studs

The answer is: whenever it is possible! You will see its great help over main cap bolts in terms of use for a heavy-duty or performance application.

Yet, why so? Let’s together check out the reason and find out whether head studs better than bolts!

First and foremost, since studs do not need to rotate as bolts do when tightening, this component allows for measuring far more precise torque values.

The studs only extend in a single axis during nut tightening because they are fixed. This explains your gaining of even considerably more uniform and accurate clamping forces.

What will also impress you about these units’ benefits is their ability to withstand abrasion.

It is because using studs reduces the amount of wear placed on the block threads. Thus, you can now extend the threaded holes’ lifespan during servicing and rebuilding.

In the case of alloy blocks, the use of such components is extremely crucial as well. Studs help to align the main cap and make it easier to install the main cap.

As such, the primary cap is less likely to slip because the studs don’t move while the cap is being clamped.

Head Studs Vs Bolts – The Differences

One remarkable difference between ARP studs vs bolts is that studs often get threaded on two ends, whereas bolts frequently feature an unthreaded center region in the shaft.

Also, the bolts always possess a head, but studs never do.

Aside from these apparent distinctions, it is also useful to consider some further aspects as differentiating the mark between bolt vs stud.

The list includes the serenity of engine congregation and separation, gasket alignment, torque, cylinder pressure, and general engine performance.

Engine Head Fastener Design

Little did you know, compared to head studs, stability and ease tend to be the main considerations in the design of head bolts more frequently.

The contributory factors for that leg up must be the engine head bolts’ capacity of standout integrity.

It is because they will normally get treated thermally in advance of being in the machining process or having threads cut into them.

Therefore, this ensures significant precision and durability in measurement.

It is not to mention that some manufacturers’ head bolts also have broad flange diameters.

As a result, there is little chance the mechanic will need to take off the valve train or the bolts when implementing cylinder maintenance.

What about head studs? These components also get thermal treatment, like bolts, to increase structural strength at high pressure.

The difference is that even though roll threads before heating offer superior mechanical power and pressure tolerance in the finished product, they can be roll-threaded before or after heat treatment.

That is why if you are waiting for a highly accurate measurement, as in head bolts, we are afraid the truth will fail your expectation.

Torque Efficiency

Another dissimilarity between studs vs. bolts is regarding torque efficiency.

The first thing you may wish to know is that a bolt needs to be torqued into place during engine maintenance or assembly.

When the strain on the engine’s combustion chamber’s cylinders starts to build up, this process produces both a twisting and upward clamping force

This whole thing leads to one result, which causes the bolt to stretch and twist.

For that reason, the bolt can no longer tie up the head stably like before.

A less dependable sealing cover in forceful engines due to the component having to simultaneously respond to two different forces will appear as a foregoing consequence.

On the other hand, a head stud is capable of tightened into position without exerting a single resultant clamping force.

Using “finger tightness,” or the amount that might be tightened with your hands only, a stud can be threaded into a slot.

The cylinder head should then be mounted, and a nut would be tightened opposite to the stud.

Instead of the fastener’s torque, it is the torque of the nut that provides the clamping. And that’s how the process helps eliminate rotating force.

As such, the stud can only deform in the direction of its vertical axis because it is being torqued in a resting state and not under any additional twisting strain.

In comparison to that of the head bolt, the outcome is a torque load that is more evenly distributed and precise.

The result is increased trustworthiness and a decreased risk of head gasket malfunctioning.

Engine Head Assembly

The one key distinction between ARP head studs vs head bolts worth mentioning is how an engine head gets assembled or repaired.

The head gasket and cylinders can be securely positioned with nearly perfect alignment using higher-end head studs precisely constructed within precise tolerances.

Utilizing cylinder head studs to construct an engine is made simpler by this feature.

Yet, head bolts get much more practical when removing a vehicle engine or performing maintenance, like a part replacement.

Master cylinders and other parts that protrude into the compartment of the engine are common in everyday-use vehicles.

As long as the engine is not completely out of the vehicle, as is the case of head studs, the cylinders can be removed using head bolts.

Simply put, head bolts tend to be more useful for personal, everyday cars, but the head stud will be your greater match for high-performance vehicles with even more outstanding power demands.

Therefore, concluding that one kind of fastener categorically surpasses the other would be incorrect.

The choice thus will come into existence by the car in question and the intended uses for it.


Above is all that you may wish to grasp regarding the comparison between head studs vs bolts.

Now that there is a full package of the benefits and downsides of each kind in your hands, it’s time to decide the tie and get right into what you want the most.

Also, don’t forget to leave a comment and let us know if any concerns are not yet resolved.

See then!

Leave a Comment