Fifth wheels, trailers, and other heavy loads all have one thing in common. When drivers want to haul them with a vehicle, they need enough power, strength, and torque available to have a successful experience.
An RV cam is sometimes called a “pulling cam.” Although it can work with recreational vehicles, this choice is a generalized type that works well in the lower RPM range for more pulling power.
If you want the right fit for your setup, contact the cam manufacturer to get the correct options for your vehicle.
They’ll need to know the valve size, rocker ratio, compression data, carb info, and other specs to give you the best fit.
Without that info, you could find about two dozen potential cams that could work for your pulling needs.
What Is an RV Cam?
An RV cam is a mild performance option designed to make more torque in the lower RPM spectrum than generate a massive horsepower number. This choice works best in situations when the RV’s motor requires an upgrade, generating about 75% of the power of a standard 3/4 cam.
The heart of every engine is the cam. If you select the right one, you’ll love everything that it can do. When you choose the wrong one, you’ll hate it until you can fix the situation.
All vehicles come with a stock cam. The choice comes from the automaker’s compromise between idle quality, smoothness, fuel economy, power, and other features.
When you swap that thing out for an RV cam, you’ll turn your engine into something that handles low RPM torque at the expense of higher RPMs and horsepower.
An RV cam has specs within the following ranges.
- About 250 to 270 degrees of advertised duration.
- Lifts ranging from .470 to .515, although there is some play in those numbers.
- An @.050 duration of 200 to 215 degrees duration.
You can find plenty of spec variation within the different RV cam designs out there, but they should all accomplish the same outcome.
What Does a Cam Do for a Motor?
A camshaft is a rotating object that contains pointed cams. This setup converts the rotational motion from the motor into reciprocal motion that generates torque for movement. They’re typically installed for automotive internal combustion engines to operate the exhaust and intake valves, although you can also find them in early electrics and mechanically controlled systems.
The camshaft also functions as a timing device. It sets the valve overlap that occurs at the center of the exhaust stroke.
When someone installs a performance camshaft, the lobe profile of the unit is tailored more to the motor’s potential.
That means you get a higher lift to increase the valve stroke’s length, allowing for more air to come through the inlet and increase power.
RV cams qualify as a “mild cam.” That means it is a little bigger than the initial stock installation. You’ll notice a bit of lope to it in return for the extra power.
What Is Engine Lope, and Why Does It Matter?
When an engine lopes, it is surging in its RPM cycle while sitting at idle. You can experience a difference of up to 1,000 RPM after installing an RV cam on some engines.
The reasons why an engine starts loping are many, which is why a thorough evaluation is necessary after experiencing this situation.
Although you can often assume that an RV cam addition causes this problem if it didn’t happen before, you’ll want to review these problems in components or systems to ensure there aren’t other issues to resolve.
- Fuel system problems.
- Ignition system malfunctions.
- PCV and EGR system concerns.
- Throttle body malfunctions.
- An idle air control valve.
- Compression issues.
- Leaks in the pressure or vacuum systems.
If there was a light lope with the engine before the RV cam upgrade, you might experience pronounced systems after finishing the work.
Since the troubleshooting process can show multiple systems at fault for this issue, a practical way to approach the diagnostic process is necessary.
Table of Potential Issues to Review After RV Cam Upgrade
The information below can help you identify a potential problem that co-exists with your RV cam changes.
If your check engine light is on, please remember to scan for diagnostic codes and check those components or flagged systems first.
| Potential Lope Issue | How to Correct the Loping Issue After an RV Cam Upgrade |
| Lopes When Cold | When the motor lopes when temperatures drop, some of the components could be worn. Look for a bad heat control valve or early fuel evaporation heater. It also helps to check fuel pump performance and to inspect the thermostatic air intake. You might also need to remove the old cam bearings. |
| Lopes When Warm | If the engine gets hot and starts loping, it could be the throttle position sensor. You’ll want to check that the heat control valve is opening. The most likely issue is that the mass air flow sensor or circuit needs a good cleaning. |
| Fuel System Issue | Numerous components in the fuel system wear out and fail. If you notice pressure decreases, it could be the pump, regulator, filter, or injectors. Each might require a thorough inspection. |
| Ignition Timing | If the loping occurred after the RV cam upgrade, you might have knocked the camshaft or crankshaft sensors while working. You’ll also want to check the intake air, throttle position, and engine coolant sensors. |
| Clogged PCV Valve | The PCV valve is usually near the valve cover. Disconnect the hoses, check the condition, and remove any foreign matter found. If you hear a rattle in one, that means it’s in good condition. When you hear silence, cleaning or replacement is necessary. |
| EGR Valve Leaks | Check the vacuum hoses in the EGR system for wear and tear. It’s not uncommon for the connection to get bumped when working on a vehicle. If it has gone bad, it’s usually possible to remove the valve for cleaning or replacement. |
| Throttle Body Problems | Engine lope can come from bore or throttle plate issues. After operating for a while, carbon starts accumulating around these items to generate performance issues. You can remove the buildup with a basic carburetor cleaner. |
| Incorrect Idle Speed | On older vehicles, the loping problem could be due to an unintentional idle speed adjustment. Check the VECI label in the engine compartment for the correct adjustment procedure. Modern vehicles have the idle solenoid or valve fail after a few years of use. |
| Ignition System Problems | The spark plug gaps might require adjustment or cleaning. If you’ve put a ton of miles on the engine before the RV cam installation, they might need to be replaced. Review the distributor, ignition coils, and cables for additional concerns. |
| Compression Leaks | Leaks can come from the cylinder head gasket to cause loping systems. This usually occurs with a high-mileage engine, but it can develop after an impact while working in the area. You can check for this issue by doing a cylinder compression test. |
| Intake Manifold Gasket | A leak from this gasket can cause engine loping. Use a piece of vacuum o fuel hoe to check for leaks by placing one end to your ear and the other while the motor idles. If you hear hissing, you’ll need to correct this problem. |
| Vacuum Leaks | Any leak from the vacuum hoses can affect engine performance. By paying close attention to the sounds coming from the engine, you can typically discover problems. |
| Clogged Air Filter | If it has been more than 25,000 miles since you last cleaned or changed your air filter, this component could be responsible for your surges. Don’t forget to clean the housing while reviewing this area. |
| Worn Camshaft Lobes | High-mileage images might have worn lobes that cause the engine to lope, even when everything else functions correctly. You’ll need to use a dial indicator to measure for this problem. If it falls outside the automaker’s specs, a repair will be necessary. |
| Leaking Valves | Any valve can start leaking to cause loping. It’s usually from carbon building that you can remove. It helps to have a compression gauge to diagnose this mechanical problem and a couple of hours of free time. |
Should I Upgrade to an RV Cam Today?
An RV cam makes sense for drivers who need extra torque for towing or hauling. Before investing in this option, it helps to review the automaker’s specs to ensure the vehicle frame can handle the power getting equipped to it with this upgrade.
I’ve always had vehicles with minimal towing and hauling power. It’s nice to have a truck for running errands, but we’ve never had a need for other purposes.
We had an SUV that we wanted to haul a fifth wheel with after a while. The original towing capacity was minimal, but that was because of the engine specs.
We went with the upgrade, increased the power, and now spend plenty of time outside the house.
This upgrade has several benefits to consider, but they aren’t universal. That’s why a complete overview of your needs, including the potential for engine lope, is necessary.
