Single Or Dual Pattern?

In the area of single and dual pattern camshafts, controversy seems to reign supreme. Proponents of the dual pattern grind feel that a standard pushrod engine will breathe better on the intake side than it does on the exhaust side. In this scenario, the exhaust lift and duration figures are greater in order to compensate for the exhaust port inability to breathe. The single pattern group point out that the exhaust is somewhat controlled by the engine cylinder pressure. The piston movement helps to force the exhaust from the combustion chamber and as a result, the intake port does not have any real advantage. This makes for a single pattern camshaft that features identical intake and exhaust lobe profiles. Which is the better of the two designs? Both have merit. Your particular combination might respond properly with a dual pattern cam grind while another similar car might show promising results with a single pattern grind.

Getting It Right ...

Remember bigger is not always better when it comes to cams. Using a cam grind that a buddy uses in his vehicle might not be the correct cam for you. Finally, keep in mind that camshafts are not selected by price alone. An "off-the-shelf, on-sale" grind might have a reduced price sticker, but is it the right cam?

Ditto with small parts such as retainers, locks and seals. This stuff isn't expensive.
Buy it new and have it matched to the other valve train components. You won't be sorry.

With these three important factors in mind, your next step should be a consultation with your favorite camshaft manufacturer. Virtually all of the major cam companies offer a technical support department that is geared toward proper cam selection and installation. The tech line staff will ask a maze of questions when you make an inquiry. Be prepared to supply accurate information -- it's no use fudging on the details -- and the cam company will be able to match a specific cam to your vehicle. Also remember that with the variety of grinds available (coupled with the many variables found in your application), the cam company might have more than one cam to suit your particular application. As a result, it might be up to you to decide which cam is best suited to your vehicle. In some cases, you might even have to test two or more grinds to arrive at the sometimes "elusive" perfect cam combination.

So what can be expected by carefully tailoring the cam to the applications? How about significantly improved performance, better throttle response, more outright engine torque (and of course, improved horsepower), superior idle characteristics and yes, even more "tunability" in the engine? And by the way, you can get all of this with a relatively simple camshaft. Just remember to analyze your personal situation carefully and don't be afraid to contact a camshaft expert in regard to his or her opinion about camshafts in your application.

Click here to read part one of CAM-ROD-ERY.

Special thanks to Crane Cams for the preparation of this article. Crane Cams can be reached at:

Crane Cams 530 Fentress Boulevard Daytona Beach, FL 32114 PH# 904-258-6174 Fax# 904-258-6167

 

Previous Stories

Back-2-Basics — 2/20/04 We gave it some 'go,' now we need some 'whoa' "CAM-ROD-ERY" (PART1) — 2/11/04 Picking The Right Low Buck Cam Combination