12v 5.9 Cummins Timing Marks You Need To Know

We have heard of people looking to find out more about the 12 v 5.9 Cummins timing marks. 

This is important to ensure proper operation of your vehicle. So, if you are in need of information on this, as well as how to tailor valve timing events, you are on the right spot! We will address these topics in this post to help you out.

Let’s dive right into it!

12v 5.9 cummins timing marks

12 v 5.9 Cummins Timing Marks Facts

Some owners talk about buying an older Cummins engine for the purpose of swapping it into their much older truck. Now, if the engine you have purchased happened to lack marks on the gears, you may be wondering how to time it properly. Perhaps, the older engine no longer has the pump, but there may be a mark on the pump mounting plate. 

If you are wondering how you may be able to time it, then this is a dilemma you would like to address. Technically, there should be 4 letters you can find on your gear. But for most people, it can be just as confusing to know which one of these you need to use.

Now, you can begin by checking your factory service manual. For instance, it should say that you need to align the “E” on your IP gear right to the “C” on your adjoining gear. But you should only do this if your adjoining gear is still intact and not pulled out.

However, if you wish, you can also go straight to “C”. There should be marks found on your drive gear located on the “0” on your gear. 

Another thing we would like to mention is that in the 5.9 Cummins, when determining the timing marks, the key should be pointed upwards. Whenever you have your pump removed, you should keep in mind that your key is in the 12:00 position prior to removal. Hence, this should be where your timing marks are placed. 

Additionally, it is typical for a set of marks on your pump gear available. This is why there is no way for you to mess this one up. 

Key Facts About Timing Events

Now let us talk about valve timing events. There are a few things you can do to tailor this process. For instance, you can add or subtract the duration. When you add the duration to the lobe, this means opening the valve and then closing it later. When you remove the duration, this leads to inverse effects.

Next, you can also retard or advance your camshaft. When you advance your cam lobe, this will open and close your valve at an earlier time. On the other hand, when you retard your lobe, this results in an opposite occurrence.

Keep in mind that your camshaft performs at complete revolution while your crankshaft tends to rotate twice to produce a complete engine cycle. Timing the camshaft is expressed in your crankshaft degrees that are relative to your piston’s location in your cylinder. This corresponds to your TDC and BDC. 

Prior to deciding if you should change the lobe’s closing or opening point through adding the duration or advancing your lobe, you need to first understand that there is an impact to the other side of your lobe. Thus, there needs to be harmony between all of your parameters. When you modify a valve timing event, there is a likelihood of certain repercussions that can directly impact the engine performance – whether in a negative or positive manner.

If you retard your camshaft, this leads to an enhanced RPM breathing, yet the idle becomes unstable – in addition to less power when you have a low RPM.

But if you advance the camshaft, the idle is more stable while the low RPM power is also good. On the other hand, breathing is poor and you get a lower power when at a high RPM.

In the case of valve timing events, there is an order of importance to consider. First is the intake valve closing, intake valve opening, exhaust valve closing and exhaust valve opening. 

Performing an overhead cam timing tends to be rather tricky when it comes to certain engines. This is why you need to consider an OEM timing procedure. This way, you can determine how your timing marks must be aligned. For a few engines, you even need to count your chain links located between the sprockets to achieve the right alignment. 

It is important to note that with the intake lobe, there are intake valve events placed according to the first two important positions. Intake events can be less forgiving when changed as compared to exhaust events. In fact, even a very small change in the design of your engine can lead to adverse effects.

The duration of your intake lobe design is crucial for producing power. When you increase the duration, this results in more air charge filling your cylinder, which is critical when at a high RPM. Thus, you need to also boost your RPM when you add duration. Cylinders have an equal air volume no matter what your RPM is.

As more duration is added, this also extends the valve’s opening and closing point. This will then positively impact the breathing as the valve is higher and in a more functional lift at the start of the induction stroke. Furthermore, as the duration is extended, this boosts the air/fuel mixture responsiveness to the piston location. 

But once again, you need to consider the drawbacks and long term effects of this process before proceeding to it.

Read More: What Happens If Ignition Timing Is Too Advanced? Problems To Consider


We hope this post has been helpful in determining the 12v 5.9 Cummins timing marks. As always, it is always helpful to consult a specialist if you are not very well versed in this process. A custom-tailored timing event may prove to have certain benefits but it is also good to be aware of some negative impacts before performing this process for your vehicle’s optimum performance.

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