What camshaft should i use

This is when all of the coils of the spring contact each other before the valve fully lifts. Valve springs should be capable of traveling at least. Advertisement B. At least. Valve to piston interference. This occurs when a change in cam specs lift, duration, or centerline is enough to cause the valve and piston to contact. Minimum recommended clearances are. Rocker arm slot to stud interference. As you increase valve lift, the rocker arm swings farther on its axis.

Therefore, the slot in the bottom of the rocker arm may run out of travel and the end of the slot will contact the stud and stop movement. The slot in the rocker arm must be able to travel at least. Advertisement 6. Distributor Gear Wear. The main cause for distributor gear wear is the use of high volume or high pressure oil pumps.

If these types of oil pumps are used, reduced cam and distributor gear life will result. However, you can increase the gear life by adding more oil flow over the gear area to help cool off the point of contact. Some engines use a thrust plate to control the forward and backward movement of the camshaft in the block. The recommended amount of end play on these types of engines is between. Many factors can cause end play to change. When installing a new cam, timing gears, or thrust plates, be sure to verify end play after the cam bolts are torqued to factory specs.

If the end play is excessive, it will cause the cam to move back in the block, causing the side of the lobe to contact an adjacent lifter. Advertisement 8. Broken Dowel Pins or Keys. The dowel pin or Woodruff key does not drive the cam; the torque of the timing gear bolts against the front of the cam does.

Reasons for the dowel pin or key failing are: Bolts not being torqued to correct specs, incorrect bolts of a lower grade stretching and losing torque, not using the correct hardened washer which may distort and cause torque of the bolt to change, LocTite not being used, or some interference with the cam, lifters, or connecting rods causing the cam to stop rotation.

A broken camshaft is usually caused by a connecting rod or other rotating part coming loose and striking it. Sometimes the cam will break after a short time of use because of a crack or fracture in the cam due to rough handling during shipping or improper handling prior to installation.

Features: Justina Reusch, Reusch Diesel. Magazine Current Issue Past Issues. Connect with us. Advertise Subscribe Contact Us. ICE vs. Compound Turbo 5. By Engine Builder. Are you building an engine for everyday driving? Most street driven vehicles seldom see the high side of 5, rpm, and most cruise at 1, to 2, rpm on the highway depending on how they are geared.

According to one cam supplier we interviewed, the best approach is to get more lift with the rocker arms and less with the cam. Sometimes the rpm drop between shifts is rpm. Cams with durations in the to degree range measured at.

Some cam lobes may have steeper or shallower ramps to change the velocity at which the valves open and close. Down the Road What type of changes or technology improvements will engine builders see in their cam selection coming down the road? Incorrect Break-In Procedure After the correct break-in lubricant is applied to the cam and lifters, fill the crankcase with fresh, non-synthetic oil. Always Use New Lifters With A Flat Tappet Cam If you are removing a good used flat tappet cam and lifters and are planning to use them again in the same or another engine, you must keep the lifters in the order they were removed from the cam they were on.

Incorrect Valve Spring Pressure Recommended valve spring seat pressure for most street-type flat tappet cams is between lbs. Mechanical Interference A. Distributor Gear Wear The main cause for distributor gear wear is the use of high volume or high pressure oil pumps. Camshaft End Play Some engines use a thrust plate to control the forward and backward movement of the camshaft in the block.

Broken Dowel Pins or Keys The dowel pin or Woodruff key does not drive the cam; the torque of the timing gear bolts against the front of the cam does. Broken Cam A broken camshaft is usually caused by a connecting rod or other rotating part coming loose and striking it. In this article: camshaft. Watch Engine Builder's latest discussions and explanations. Shop the latest Engine Builder merchandise. Roller Camshaft versus Flat Tappet Camshaft. More Info. Related Articles.

Once you're ready to start selecting valve train components, we have some useful tips and tools that should boost your performance. We discuss proper valve-springs, pushrod length, and rocker arm ratios. One of the most important parts of your racing operation is the engine.

This article gives a detailed overview on how to maintain your engine to get the most out of it for as long as possible. Also learn some tips to prolong the life of your engine. Picking a proper camshaft for your project can rapidly deteriorate into chaos.

So many possibilities. Want a little advice? Click here! Learn the basics to engine performance like; how does a cam work? Advertisement Consequently, you want cam lobes that open the valves quickly, hold the valves open when airflow is greatest, and then close the valves quickly to minimize compression losses.

Roller cams are much better in this respect because a roller on the bottom of a lifter can follow a more radical lobe profile. A roller cam can open and close the valves faster for more total airflow with the same lift and duration.

Advertisement Valve Timing Issues Valve timing includes the points at which the intake valves open and when they close, and when the exhaust valves open and when they close. Of these four timing events, intake valve closing actually has the greatest impact on now much power a particular camshaft will make.

If the intake valve closes too soon, the cylinder may not fill completely during its intake stroke. Holding the intake vale open longer allows more airflow into the cylinder — up to a point. If the intake valve remains open too long past the point where the piston has reached and passed bottom dead center, the upward motion of the piston can start to reverse airflow and push air back out of the intake port. Advertisement The point at which the exhaust valve opens has the second greatest impact on performance.

If the exhaust valve opens too soon, cylinder pressure may be lost before it can complete its work. If the exhaust valve is opened too late during the exhaust stroke, it increases the pumping effort required to push the exhaust out of the cylinder. The closing of the exhaust valve and the opening of the intake valve, by comparison, have the least impact on performance. The point at which the intake and exhaust valves open and close is determined by the ramps on the cam lobes.

As soon as the lifter or follower reaches the point where the ramp starts from the lobe base circle, the valvetrain begins to move and starts to open the valve. The opening point may be measured at a specified amount of lift such as. Advertisement For example, a typical street performance cam might have a listed duration of degrees for the intake and exhaust valves measured at. The lobe separation between the peak lift points of the intake and exhaust valves might be degrees.

Street cams and cams that are designed to produce more low to mid-range torque typically have less overlap and more lobe separation, while cams that are designed more for maximum high speed power have more overlap and less lobe separation. Confusing Calculations Comparing one cam grind to another can be tricky because camshaft suppliers often measure their cam specifications differently. If duration is measured at. Generally speaking, the longer the duration the higher the rpm range where the cam makes power.

Short duration cams are good for low speed torque and throttle response while long duration cams are best or high revving engines that need to make lots of top end power. Cams with durations in the to degree range measured at.

Once you go beyond to degrees of duration, intake vacuum starts to drop. This upsets idle quality and affects the operation of computerized engine control systems. Advertisement Performance cams typically have durations ranging from up to degrees or more.

A cam with a duration of degrees of higher will typically produce the most power from 3, to 7, rpm. Cams from two different manufacturers may have identical lift and duration specs, but have considerably different performance characteristics because of the shape of the lobes.

A lot of development work has gone into revamping lobe profiles in recent years to optimize performance, and many cam suppliers have introduced new product lines that reflect these improvements. Advertisement Some cam lobes may have steeper or shallower ramps to change the velocity at which the valves open and close.