Camshaft Testing
Here at Torque Developments International we’re on a mission to merge tactile skills of Craftsmanship skills with the latest technologies available. A new addition to our technical capabilities is a scientific-quality camshaft analyser from Performance Trends.
Camshafts are a critical component for determining engine performance so it’s crucial to understand the lobe geometries and relative positions in order to accurately predict the outcomes. In simple terms, we look for the fastest opening ramps and slowest closing ramps (limited by valve control, NVH and wear-rates) to achieve maximum valve-open time, but this must be matched to the Static Compression Ratio (SCR) in order to not reduce the Effective Compression Ratio (ECR) – otherwise the engine performance will be compromised.
We’re able to digitally analyse camshaft profiles for the following parameters:
- Camshaft lift
- Duration
- Lobe separation
- Acceleration and deceleration
- Asymmetry
- Seating velocity
- Minimum tappet diameter required
- Lobe runout
The camshaft analyser data can also directly input data into our Engine Analyser software to more accurately determine the performance trends of an engine package. This software allows us to accurately predict how the engine performance will be affected by making changes to the valve-lift, valve-duration and valve-timing. It also provides data on when valve-float (AKA valve-bounce) will occur, and see how that is affected by making changes to the valve-train.
Once analysed and performance-predicted, we can then recommend changes to the camshaft specifications in order to achieve the objectives, and then select profiles from existing catalogues or suggest new specifications. For camshaft manufacture we work with HKS, Toda Racing, Cosworth, Kent Cams, Piper Cams, Kelford Cams, Cat Cams etc.
In additional to our camshaft testing and analysis, our facilities also include airflow test rig, dynamic crankshaft balancing, hub mounted chassis dynamometer, CNC milling, ECU calibration, and general machine shop processes.
A full list of our Services and Capabilities can be seen here.
For Camshaft Testing information and bookings please contact us
Here’s a short description of camshaft characteristics for a better understanding from Wikipedia :
Duration
The camshaft’s duration determines how long the intake/exhaust valve is open for, therefore it is a key factor in the amount of power that an engine produces. A longer duration can increase power at high engine speeds (RPM), however this can come with the trade-off of less torque being produced at low RPM.[16][17][18]
The duration measurement for a camshaft is affected by the amount of lift that is chosen as the start and finish point of the measurement. A lift value of 0.050 in (1.3 mm) is often used as a standard measurement procedure, since this is considered most representative of the lift range that defines the RPM range in which the engine produces peak power.[16][18] The power and idle characteristics of a camshaft with the same duration rating that has been determined using different lift points (for example 0.006 or 0.002 inches) could be much different to a camshaft with a duration rated using lift points of 0.05 inches.
A secondary effect of increased duration can be increased overlap, which determines the length of time that both the intake and exhaust valves are open. It is overlap which most affects idle quality, in as much as the “blow-through” of the intake charge immediately back out through the exhaust valve which occurs during overlap reduces engine efficiency, and is greatest during low RPM operation.[16][18] In general, increasing a camshaft’s duration typically increases the overlap, unless the Lobe Separation Angle is increased to compensate.
A lay person can readily spot a long duration camshaft by observing the broad surface of the lobe where the cam pushes the valve open for a large number of degrees of crankshaft rotation. This will be visibly greater than the more pointed camshaft lobe bump that is observed on lower duration camshafts.
Lift
The camshaft’s lift determines the distance between the valve and the valve seat (i.e. how far open the valve is).[19] The farther the valve rises from its seat the more airflow can be provided, thus increasing the power produced. Higher valve lift can have the same effect of increasing peak power as increased duration, without the downsides caused by increased valve overlap. Most overhead valve engines have a rocker ratio of greater than one, therefore the distance that the valve opens (the valve lift) is greater than the distance from the peak of the camshaft’s lobe to the base circle (the camshaft lift).[20]
There are several factors which limit the maximum amount of lift possible for a given engine. Firstly, increasing lift brings the valves closer to the piston, so excessive lift could cause the valves to get struck and damaged by the piston.[18] Secondly, increased lift means a steeper camshaft profile is required, which increases the forces needed to open the valve.[19] A related issue is valve float at high RPM, where the spring tension does not provide sufficient force to either keep the valve following the cam at its apex or prevent the valve from bouncing when it returns to the valve seat.[21] This could be a result of a very steep rise of the lobe,[18] where the cam follower separates from the cam lobe (due to the valvetrain inertia being greater than the closing force of the valve spring), leaving the valve open for longer than intended. Valve float causes a loss of power at high RPM and in extreme situations can result in a bent valve if it gets struck by the piston.[20][21]
Timing
The timing (phase angle) of the camshaft relative to the crankshaft can be adjusted to shift an engine’s power band to a different RPM range. Advancing the camshaft (shifting it to ahead of the crankshaft timing) increases low RPM torque, while retarding the camshaft (shifting it to after the crankshaft) increases high RPM power.[22] The required changes are relatively small, often in the order of 5 degrees.[citation needed]
Modern engines which have variable valve timing are often able to adjust the timing of the camshaft to suit the RPM of the engine at any given time. This avoids the above compromise required when choosing a fixed cam timing for use at both high and low RPM.
Lobe separation angle
The lobe separation angle (LSA, also called lobe centreline angle) is the angle between the centreline of the intake lobes and the centreline of the exhaust lobes.[23] A higher LSA reduces overlap, which improves idle quality and intake vacuum,[22] however using a wider LSA to compensate for excessive duration can reduce power and torque outputs.[20] In general, the optimal LSA for a given engine is related to the ratio of the cylinder volume to intake valve area.[20]
Functionality
Camshafts are integral components of internal combustion engines, responsible for controlling the opening and closing of the engine’s intake and exhaust valves. As the camshaft rotates, its lobes push against the valves, allowing the intake of air and fuel and the expulsion of exhaust gases. This synchronized process is crucial for optimizing engine performance, fuel efficiency, and emissions control. Without precisely engineered camshafts, the smooth and efficient operation of an engine would be compromised.[24]