General Tips

High Lift Cams
When changing to a higher than stock lift cam, several items must be checked to ensure long engine life and high performance. Spring coil bind, correct pressures, retainer to guide clearance and piston to valve clearance are just a few of the more common considerations. There is no exact formula to tell when you are getting into trouble, so to avoid serious problems, it is better to double check these things when installing a cam. If ever unsure, contact CAM HELP® at 1-800-999-0853.

Springs
By far the most common problem encountered when installing a new high performance camshaft is the incompatibility of the existing valve springs to the new cam. Factory valve springs are designed to work with a certain lift cam, and since most aftermarket cams have higher lift, the springs must be addressed. It is highly recommended and a requirement of the warranty that the suggested springs be installed along with any COMP Cams® camshaft.

Valve Stem Oil Seals
When changing to a higher than stock lift camshaft, it is common to have a clearance problem between the bottom of the spring retainer and the top of the valve stem oil seal. Before final assembly of the heads, install one seal, one valve and one retainer without the spring. Measure the distance between the top of the seal and the bottom of the retainer to be sure that it is greater than the lift of the valve by at least .050”-.060”. Be sure to take into account any extra lift due to higher ratio rocker arms.

Flat Tappet Break-In
All flat tappet cams require special attention during the break-in process. Special springs and certainly tender loving care will be required to ensure long life of the cam. Please refer to the instructions in your cam box for complete procedures. If ever in doubt, please call the COMP Cams® CAM HELP® line at 1-800-999-0853.

High Ratio Rocker Arms
A higher than standard ratio rocker arm moves the pushrod closer to the rocker arm shaft. It then becomes necessary to check

the clearance between the pushrod and the head where the pushrod passes through the head. This is a very common problem and should be checked when a rocker arm ratio change or pushrod diameter change is made.

Rocker Arm Geometry
Proper rocker arm geometry is necessary to ensure the maximum benefit from any cam design. Camshaft base circle, block deck height, cylinder head design and lifter design all contribute to possible errors in geometry, which must be compensated for with pushrod length and shaft height. Usually, a longer than stock pushrod will be necessary in a high performance engine, but care must be taken to choose the correct length.

Fuel Pump Pushrod
All Chrysler “B”, “RB” and Hemi engines use a fuel pump pushrod to actuate the fuel pump. The fuel pump must be removed and the rod dropped away from the cam prior to camshaft removal. Failure to do so will result in damage to the cam, pushrod or both.

Rocker Arm Adjustment/Lifter Preload
All but a few Chrysler engines were equipped at the factory with non-adjustable rocker arms. Anytime a solid lifter camshaft (either roller or flat tappet) is used, you must also use the adjustable rocker arms and appropriate pushrods.

When installing any high performance hydraulic camshaft, the lifter preload is something which must be considered. Too little preload will result in a noisy valve train, and too much preload will result in tight valves and a poor running engine. Either condition can result in less than expected performance or engine failure. After the cam, lifters and rocker arms are installed and prior to installing the intake manifold, you must check the plunger depression in the lifter. With the cam on the base circle (valve closed) the plunger in the lifter should be depressed .040”-.060”. With nonadjustable rocker arms, you must change pushrod lengths to obtain proper lifter preload. This is a delicate and time consuming process, so if you have any questions, contact the CAM HELP® line at 1-800-999-0853.