What makes an engine lope?

Lope is a result of the intake and exhaust valves both being open at the same time. This is called overlap. Mild cams have little or no overlap at any valve opening that makes a difference. Hotter aftermarket type cams have a lot because it aids high RPM breathing.

What causes a lope?

What Makes A Truck Lope? It's called lope because of overlap between an exhaust valve and an intake valve when they are opened. There will be more overlap between lines if there's more overlap. The purpose of the exhaust duration is to calculate what the duration will be.

Why do performance engines lope?

A compression leak may come from a cylinder head gasket and cause the engine to lope sometimes. This usually happens because the engine has high mileage, or a particular failure, like overheating, caused the gasket to blow. To check for a leaking head gasket, do a cylinder compression test using a vacuum gauge.

What makes a cam have a lopey idle?

what makes the cam have that lumpy sound? The overlap of the exhaust valve closing and intake valve opening causes the engine to be inefficient at low speed which results in the lumpy idle. The closer the Lobe Seperation Angle the more the overlap, the more duration the more (typically) the overlap.

Why is my car loping at idle?

If an engine is not getting enough fuel (this is called “running lean”), due to fuel pressure (regulated by the fuel pump and regulator), restricted fuel injectors, a vacuum leak or really anything that throws off the fuel mixture going in to the engine, this can cause the surge.

Lobe Separation And What It Means

What causes RPM to fluctuate while idling?

Worn out or fouled spark plugs can cause rpm fluctuations. Check the engine vacuum and make sure there are no leaks. Leaks in the engine vacuum can cause rpm fluctuations. Replace the fuel filter if it is clogged or dirty.

What causes engine to rev up and down?

If the engine can't keep idling, it will keep trying to get the engine revved up to compensate. The cause of the erratic engine you're experiencing could be a vacuum leak, sensor failure, or an EGR system malfunction.

What is considered a mild cam?

In general, a stock replacement camshaft with duration of less than 200 degrees will have a lobe separation angle of more than 114 degrees. An RV or towing camshaft, which is considered a mild performance or an economy cam, will often have a narrower LSA, between 112 and 114 degrees.

What does lobe separation do for a cam?

Typically, narrower lobe separation develops peak torque at lower rpm and widening the separation tends to build peak torque higher in the rpm range. Nitrous engines, which make plenty of power and torque, often run wide lobe separation angles to moderate cylinder pressures and temperatures.

What does an aggressive cam do?

Maxing Engine Performance. Consider installing a performance camshaft. Performance cams increase the duration and timing of the valve openings during the engine stroke, increasing horsepower and making your car accelerate more quickly.

What makes a motor chop?

LSA (lobe separation angle) determines the choppiness, it has to do with the overlap of when both valves are open, as in when the exhaust valve is closing and the intake valve is opening to pull fresh fuel in on the intake stroke after pushing out the burnt fuel.

What is a hotter cam?

The "Hot Cam", as others posted, is a GM Performance Parts hydraulic roller cam that's a popular replacement for the ZZ4 cam as it has more lift and duration. A "hot cam" can mean any cam that is bigger than stock.

Does cam duration affect idle?

Again, keeping all else constant, more duration will make the engine less efficient at low rpm, with more overlap dilution of the induction charge, and the later intake valve closing reducing the trapping efficiency. Therefore, a long-duration cam will cause rough running at idle (lope) and a loss of low-rpm torque.

What part of cam makes car lope?

Lope is a result of the intake and exhaust valves both being open at the same time. This is called overlap. Mild cams have little or no overlap at any valve opening that makes a difference. Hotter aftermarket type cams have a lot because it aids high RPM breathing.

What is camshaft overlap?

A: Overlap is when the intake and exhaust valves are open at the same time. It is expressed in degrees of crankshaft rotation. Not all camshafts have overlap. If they do, it happens at the end of the exhaust stroke and the beginning of the intake stroke.

What does cam duration do?

DURATION: Duration is how long the cam holds the valves open. It's expressed in degrees of crankshaft rotation (remember, the cam rotates at half the speed of the crank). A 280-degree-duration cam holds the valves open longer than a 260-degree-duration cam.

What does retarding a cam do?

Advancing or retarding the cam pushes the centerline of the camshaft to one side or the other of the crankshaft centerline. This changes the Timing of the valve opening and closing events, in relation to the position of the piston in the cylinder.

How do I check my lobe separation?

To check your LSA you calculate it by adding the intake and exhaust Lobe Centerline figures together and dividing their sum by two (Ex: 112 intake Centerline + 116 exhaust Centerline = 228 / 2 = 114-degree LOBE SEPARATION ANGLE).

Should I advance my cam timing?

Advancing or retarding a camshaft's timing from its original "zero" position causes the valve events to happen either earlier or later in the engine's cycle. A camshaft that is advanced four degrees will cause each opening and closing event to occur four degrees of rotation sooner than before.

What does Stage 3 cam mean?

The Stage 3 cam is designed to work with some larger valves, port work, and upgraded carburetor or EFI system. This cam starts moving the power band a little higher in the RPM range (2500-6000). This is the biggest cam we recommend for a street application.

What is the difference between a Stage 1 and Stage 2 camshaft?

Most Stage 1 type modifications are typically in the +10-15% power increase over stock. Stage 2: this is typically referred to an engine with a performance cam upgrade as well as the other components within a Stage 1 combination. A typical Stage 2 has generally +20-25% more HP than stock.

Why are my revs bouncing?

In an automatic transmission, transmission fluid is used to lubricate, act as a coolant, as well as deliver power from the engine to the transmission. When the transmission develops a leak and fluid levels fall, a vehicle will begin to rev at higher levels as a result of the gearbox band or torque converter slipping.

Why does my RPM needle bounce when accelerating?

If your car's RPMs fluctuate while accelerating, then you may be dealing with an engine vacuum leak in the engine. A vacuum leak is when there is an interruption in the air flow in the intake manifold or exhaust system of your vehicle.