A Practical understanding of Camshaft Selection

There is so much debate around camshafts, which is the best to use, mild or wild duration, high or mild lift, which degree makes the most power, and if it works on the track, will it work for me? These questions are generally thrown around on forums and social media networks with some realistic and unbelievable results, dyno charts, flow charts and claims of power that we all want but are not in our budget or best interests for our everyday drive.

Fitting a Performance Camshaft is the most economical way of adding more power to your engine. Back in the 1960’s Camming was to cars what the Internet is for computers these days. Although technology has changed over the years the crucial Camshaft Selection Process has not.

“The camshaft is the brain of your engine, mechanically opening and closing the valves. It dictates when the valves open and close, how long they are open and closed and when they are open and closed in relation to crankshaft position.”
The camshaft has a very large effect on the type of power your engine makes.
Within the Performance Trade, Products , Mechanics ,Tuners & Salesman get slandered daily due to incorrect applications which are mainly caused by misinterpreted or misguided information or lack of knowledge.
Responsibility needs to be taken for poor choices and regardless of good advice fitting a 288-degree camshaft to a 1400 Chico is a bad idea as well as joining a thread to slag off the entity that questioned this choice to begin with. With less lowdown power than standard and all power above 5000 rpm, drivability is seldom considered. Although there are salesman out there that will sell sand to the Arabs the final decision is taken by the purchaser, so understanding a bit more about the product should assist you in a wiser choice.
Fitting a 300 degree Camshaft to an everyday driver is not the answer so please be careful as to the advice you take as there are many camshaft durations and combinations for the track but we are very limited to availability for street usage in comparison.
I am sure that this basic information will help you in understanding a bit more about how to choose your first or next camshaft when spending your hard earned cash on improving your ride.

Realise your needs before you select
 When it comes to Performance Camshafts we must consider factors such as engine capacities, compression ratios, type of fuel being used, carbs, sidies, ITBs, fuel injection, street or track use, management type, the list goes on!
Phases of camshafts range from everyday mild street to full Race Spec, Wild duration and high lift.

We can look at the following for a better idea of the difference between a mild & wild camshaft and how drivability can be affected on a VW Golf:
1 ) “A” claims a 288-degree camshaft in an 1800 Golf works great and that anyone with a golf that fits anything smaller is wasting their time and money. What is not mentioned is that this vehicle is driven hard at high rpm on weekends at drags. Power is above 4000rpm with a rough idle, with no concern for the lowdown torque loss or high fuel consumption.
2 ) “B”  drives at a max range of 3500rpm in his 1800 Golf to work and back daily enjoys the standard lowdown torque but feels he has to drop a gear up hills. A 272 degree cam will be a good choice as existing lowdown torque and fuel efficiency remain and a power gain from around 3000rpm is achieved.
 If “B” fits a 288 a rough idle is created without useable power below 4000rpm. Taking into consideration his driving style the 272 will suit his requirements better. He may not obtain the gains of the 288 but from a driveability point of view his gains are sufficient for his requirements.
With max power there will always be a trade-off so realising the limitations and side effects of the incorrect selection and application is of high importance. By gaining 10kw with a  288 degree camshaft  on a standard VW 2lt 8v is a great increase but the power is all above 4000rpm and there is no apparent gain below that , so gaining higher up in the rev range has a sacrifice of lowdown torque loss.
Fitting a milder camshaft  will increase the usable power for instance from 3000rpm or 3500rpm where you will be able to use it more to your advantage in everyday usage .

Camshaft Facts never mentioned…
Camshaft Profiles in SA are generally copies of other well-known brands such as Schrick who develop and produce camshafts from street to F1 applications.
Anyone who claims they are the “Cam Father” in SA is only kidding themselves as profiles are mostly derivatives of World renowned brands. Most profiles are copied and changed to suit requirements.
Camshafts Profiles in SA are all much of a muchness with a few minor changes such as additional lift and lobe centre changes but the basis is the same copied profile.
Changing the lift, base circle size, and lobe centres and suddenly you have a newly designed camshaft profile?  It’s like calling a Fiat a Ferrari!
For example, a 288 profile with a standard 110-degree lobe centre can be widened or narrowed :
 If the lobe centre is narrowed to 106 degrees on a 288-degree camshaft a claim of a new design of a 284-degree Camshaft ?  or a 276 with 114 degrees Lobe centre and a 280 degree is born …. Don’t be Fooled – THE FACT IS, the remain 288 & 276-degree camshafts but with a different lobe centre.  
 
Camshaft basics …
Three main Camshaft types :
Re-profiled – Using your existing camshaft is generally only suitable for mild durations anything too wild will result in an undersized base circle and depending on how much base circle is lost in the grind valves may need to be lengthened to compensate for this loss.
Billet – We all refer to Performance Camshafts as a Billet , this is incorrect , a Billet is turned from a steel bar and is Nitride Hardened after grinding.
Blank – Generally made from a Chilled Iron Casting  ( Chilled Cast ) and has far superior wear characteristics than any other material.  Chilled Cast material is exceedingly scuff-resistant and is the only material for producing Quality OHC Performance Cams.
The most important thing in preventing premature wear of a camshaft is the material type,  thus the reason for most Performance Camshafts being manufactured the Chilled Cast method.
What is a CHILLED CAST?
When the camshaft is cast in the foundry, the iron is poured and hardens off very quickly (known as Chilling) this causes the material to form a matrix of carbide on the cam lobe.

This material will cut glass!
A Chilled Cast Camshaft may cost more than re-profiling your existing camshaft but the wear characteristics speak for themselves.

Degrees , Lift etc … What does this all mean ?
Camshaft technology & design is a very complex art, this article is not to develop more “Cam Fathers “ but merely as a basic guideline.
Duration This is the amount of time, in crankshaft degrees, that the valve is off its seat.
We hear a lot around camshaft lobes that do not measure the same from one lobe to the next on the same camshaft this is due to the following design patterns : 
Single Patterns have the same duration on the intake and exhaust lobes( Intake & Exhaust lobe  measurements are the same )
Dual Patterns have slightly or completely different durations on intake and exhaust (Intake & Exhaust measurements will differ)
Cams with different durations on intake and exhaust are also referred to as Split Pattern Camshafts.
What makes one cam better than another?
There are many opinions and claims but there is no fair way to compare Single and Dual Pattern Camshafts.
Both work quite well and based on this there is no benefit in choosing one over the other.
On any dyno you will always be comparing apples to oranges. 

Lift This is how far the lobe of the cam will push the lifter in a linear distance.
Lift is measured by subtracting the base circle diameter from the diameter at the highest point. ( differs with rocker arm ratio types )
The bottom line on cam lift is that it is pointless to go overboard. All newer designs have adequate lift for the operating range of the cam. The minimal gains from an extra high lift cam are not worth the extra work in a street vehicle.
LSA: Lobe Separation Angle Lobe Centre Angle or Lobe Displacement Angle.
This is a measurement in camshaft degrees that tells you how far apart the centrelines, or maximum lift points of the exhaust and intake lobes are.
Overlap: the amount of time in camshaft degrees when exhaust and intake valves are both open.

Intake and Exhaust Centerlines:
Intake Centerline:
This represents where the intake lobe’s peak lift is in relation to crankshaft rotation. It is the point of maximum lift of the intake lobe and is measured in crankshaft degrees.
Exhaust Centerline:
This represents where the exhaust lobe’s peak lift is in relation to crankshaft rotation. It is the point of maximum lift of the exhaust lobe and is measured in crankshaft degrees.

How does this affect my engine’s power?
Duration Increasing duration will move the power and torque curves up in the RPM range. Longer durations generally suite higher RPM applications as at high RPM the amount of time the valve spends open is smaller than at lower RPMs. Keeping the valves open longer allows the cylinders to fill with more air and fuel.
 More duration generally means more power in the higher RPM range.
LSA Lobe separation for a given duration will alter a few things.
Narrower =  increased overlap  , this means Less lowdown and more high up power , good for Race Cars , Carbs & power.
Wider = broader power band, good for Street use, EFi & Fuel Efficiency.
Changing the LSA also changes the valve timing by opening the exhaust valve sooner and closing the intake valve later
Overlap
Overlap and LSA are closely tied together.
 More overlap can fool electronics and cause tuning headaches with EFI.
 Increasing overlap gives  a rougher idle due to the valves opening together for a longer period . Exhaust gasses are pushed into the intake at low speeds causing an uneven vacuum and fuel metering. At higher RPM it works better due to the fast-moving exhaust gasses making a slight vacuum which helps by creating new intake charge known as scavenging.
ICL Intake centreline can be altered either by the camshaft grind or the use of an Adjustable Vernier Pulley that allows us to advance or retard timing, this enables us to fine-tune where the power comes in.
Lift
Many believe that the higher the lift the better the performance as the valve opens further, this may be true but consider the following :
 Lift does not change the RPM range but it will alter how much area is available for flow.
Getting more air in is a serious benefit on any engine but generally airflow is restricted by the standard cylinder head , throttle body and intake system.
Keeping in mind that lift is best matched to your cylinder head, a head flows more as it lifts more. If your head starts decreasing flow above an 11,5mm lift, there is no reason for an 11,7 – 12mm lift.
More lift is better up to the point where the head starts losing flow.
A higher lift works better with a higher or improved Airflow, therefore combination is crucial when considering upgrading your camshaft and engine.
Ensure that the valves, retainers, and springs can handle the extra lift without coil binding, if not they should be upgraded.
High lift on a short duration cam is very hard on the lifters and causes valve to piston problems (especially with narrow lobe centres), valve spring retainer to valve guide/seal interference, rocker arm interference, and valve spring coil bind.  All of this must be checked and corrected before a high lift cam can operate properly.
Excessive lifts will cause more problems than they are worth in an engine that is not worked or fully race-prepared.

I think we have covered enough basics to assist you in choosing your camshaft more accurately and remember you can boast all you want on forums about power figures and who has the biggest and best camshaft, after allthe proof is in the product selected for your application.