This section is designed to help in selecting the correct camshaft for your engine. There are many different programs available on camshaft selection Ivan Tighe Engineering are currently investigating these programs. The programs tested are very accurate if a Chevrolet V8 is the test engine, but if a 16v Suzuki is tested, in particular parameters the selection does not work on the dynometer.

The most important thing to remember is that there are 2 or 3 different profile combinations that will have identical results in an engine, particularly in a road driven vehicle. The engine may have different characteristics but produce the same H.P. & Torque.

250º - 264º

Advertised Duration.

195º - 210º

0.050" Duration.

This range is designed for bottom end, better economy and better throttle response designed for a standard engine, if a engine has been modified this range of camshaft will still perform well, but wider lobe centres may be required to achieve best results.

Suitable for towing and heavy-duty applications, smooth idle, high vacuum for both auto and manual use. Typical lobe separation of 1100 - 1130

 

Power Range:

Small Capacity

1850 - 5200 R.P.M.

Large Capacity

1250 - 4500 R.P.M.


264º - 272º

Advertised Duration.

210º - 225º

0.050" Duration.

This range is designed more for the midrange, smooth cruise and slightly lopy idle. Still suitable for automatic transmission using standard stall converter. Modified Distributor and exhaust system recommended. Good for towing in larger capacity engines.
Higher compression ratio not required, Larger valves not recommended.
Typical lobe separation 108º - 112º.

 Power Range:

Small Capacity

2000 - 5800 R.P.M.

Large Capacity

1500 - 5000 R.P.M.


272º - 290º

Advertised Duration.

225º - 245º

0.050" Duration.

This range is designed for modified street, limited modification race or speedway. For single carburetor (350 holley), 6 cylinder engines. Twin carburetors recommended for 4 cylinder engines.
For road application suggest, Ported Cylinder head, Bigger Valves, Balancing and higher compression ratio (9 or 10:1). Distributor also requires regraphing. Lopy idle, if Automatic transmission is used a higher stall will be required. A wide area of camshaft selection, different durations and lobe centre lines used to give different power ranges.

- Lower rear axle ratio may be required to achieve the best from the modifications. Typical lobe separation of 106º - 110º

 

Power Range:

Small Capacity

2600 - 6500 R.P.M.

Large Capacity

2200 - 6000 R.P.M.

 NOTE: Valve spring retainers must be checked for suitability, depending on piston choice, valve to piston clearance will also require attention.


300º +

Advertised Duration.

250º +

0.050" Duration.

This range of camshaft is more for engine design rather than for camshaft replacement The engine most be designed and built with the design of the camshaft in perspective.

  • Multiple carburetors recommended for both 4 and 6 cylinder engines.
  • Minimum of 600-750 C.F.M. Carburetor recommended for V8 engines, size of carburetor depending on engine capacity.
  • Valve springs must be checked for suitability, Harmonic testing recommended if high R.P.M. is to be used.
  • High compression recommended to achieve best performance (Above 10.5:1}
    Typical lobe separation of 100º - 106º

 

Power Range:

Small Capacity

4200 - 10000 R.P.M.

Large Capacity

3700 - 8500 R.P.M.


Points to keep in mind when selecting your camshaft.

 The following remarks are intended to help you select the correct camshaft, if you have a camshaft that works very well in one type of engine, this will allow you to adapt from one engine to another.

 
  • If the cylinder head is flowing more (has been ported) the lobe centreline can be closed. This will give the best benefit of the improved airflow.
  • If the capacity of the engine is smaller the lobe centrelin~hold be opened to achieve the same results.
  • The exhaust profile is much less critical on low compression engines. Ivan Tighe Engineering recommends a smaller exhaust profile on low compression, small engines.
  • It is highly recommended that for the best results, the flow figures for the cylinder heads are used. This helps to give the engine the correct balance inlet to exhaust.
  • The closer the lobe centreline the harder the engine will "come on the cam". Ivan Tighe Engineering use wider lobe centrelines on Speedway application, for this reason.
  • If a hydraulic cam is being replaced with a solid cam, the 0.050" duration needs to increase by 80 or 100 to obtain the same effective duration.
  • For every 10 CI. (200cc ) the duration needs to be increased by 10 at 0.050" to have the same effective duration. This is more effective in V8 engines rather than 4 CYL. engines.
  • The inlet profile has more influence on the power range than the of the higher performance 4 Valve engines, have a larger inlet than exhaust A difference of up to 20º is not unusual. This gives the engine more flexible power.
  • The exhaust profile can dictate to the inlet, the exhaust can help the cylinder fill and clean the combustion chamber on overlap. This allows more mid range, but with a loss of fuel efficiency and response.
  • The camshaft designers in the U.S.A. use the large exhaust concept as to sell the customer the camshaft they require. The camshaft does not have a larger exhaust, but a smaller inlet profile. This allows the camshaft to be solid as a 280º duration but has the characteristics of a 270º camshaft, because the inlet has more influence on the power band.