Are you hearing a sudden engine knock? Is your engine running rough?

These can be signs that your camshaft is failing.

Replacing a camshaft can be an expensive and frustrating repair, especially if it needs to be done outside an engine overhaul.

You want to do everything you can to keep your engine running for miles to come and avoid unnecessary downtime. That's why we're taking you through some problems you could see with the camshaft for the Cummins ISX.

The ISX has gained a bit of a reputation for issues with camshafts. In this post, we're looking at where you might be seeing these problems, and what you can do to keep your ISX running great!

WHY DID THE CAMSHAFT IN MY ISX FAIL?

If you're experiencing a camshaft failure in your ISX, you probably want to know what went wrong so you can avoid it in the future.

CHANGES TO THE ISX CAMSHAFT

Cummins has changed the camshaft rollers multiple times to get more surface area between the roller and the cam. But the differences in the camshaft lobes are designed to spread out pounds per square inch.

That's basically the load on the camshaft.

So, you would think that the widest camshaft you could get would be the best. The problem, however, is that the more surface area you have in contact, the more surface area there is to fail.

WHAT'S THE IDEAL CAMSHAFT FINISH?

There's a lot to do with startup. You want to have a finish on the camshaft that's coarse enough that when the cam starts turning for the first time, it gets the roller to turn with it and the roller doesn't slide. That's because you have a roller that has heavy down pressure on the camshaft.

So, if your roller doesn't start turning with the camshaft, it will slide, which is the starting failure point.

The way to avoid slide is to narrow the camshaft so your pressure is higher. Or, you make the surface more coarse. In the end, though, that can work against the longevity of the camshaft.

You might wonder, then, "How wide and smooth should I make it?" If you make it so wide and smooth that it doesn't even roll, then you've gone too far.

That's the biggest battle with the camshaft, and one of the big reasons gasoline engines have started to move away from camshafts. There's just too much opportunity for wear.

LOOK AT YOUR ISX CAMSHAFT WHEN YOU'RE OVERHAULING YOUR ENGINE

It's a good idea to take a look at your ISX camshaft when you have the engine apart for overhaul.

You might not think you need to take it in to get a valve adjustment done, because it's running fine, but you might have valve clearances expanding or contracting. This can cause the cam rollers to beat on the cam.

INSPECT YOUR LOBES AND ROLLERS

When you're doing an overhaul, take a look at your lobes and rollers.

Make sure they're in good shape before you put it back together. They can and do fail, and it's a lot of work to take it back apart to change a cam.

REGULAR DIESEL ENGINE OIL CHANGES ARE KEY

It's also important to do regular oil changes to ensure everything is working properly. It can be tempting to try and push it a few more thousand miles, but this can cause damage to your camshaft. And it could end up costing you more money in repairs than if you'd changed the oil regularly.

Doing oil samples can also help you diagnose an issue with your camshaft. It gives you a chance to check for metal shavings.

These are often a symptom of failure and can damage other lobes on your cam. They can even travel downstream and damage other components.

ISSUES WITH ROCKER ARMS IN THE ISX CAMSHAFT

Some ISX engines have had an issue with rocker arms that have led to camshaft problems.

Some productions of rocker arms prevented the correct amount of oil from flowing, which starved the components. These rocker arms begin to stick and smack the camshaft, which leads to lobe flattening.

To fix this problem, both the rockers and cam will need to be replaced, otherwise the faulty rocker arms will damage your new camshaft as well.