Project Dodge Neon - Crane Cam Installation - Sport Compact Car Magazine

In our last edition of Project Neon (Feb, '02), we applied the basic bolt-ons to our Neon's SOHC engine in hopes of eliminating the cheap rental car power output blues.

Our carefully chosen bolt-ons were, in our opinion, a great success, but it took a lot of parts. Adding a CNNP exhaust, AEM intake, Unorthodox pulley, Mopar Performance ECU, Kirk Racing header, Random Technology cat, RC engineering throttle body, and advancing the cam two degrees with an AEM cam gear provided up to 16 hp and 18 lb-ft of torque.

Now, we're going deeper into our Neon's engine in hopes of getting more than just acceptable performance.

Camshaft
When reviewing the specs of the stock Neon camshaft, it became apparent our engine needed help. For whatever reasons, probably emissions compliance and fuel economy, Chrysler has put an amazingly small cam into the SOHC engine. This conservative tuning is probably why our engine's power drastically falls off above 5000 rpm. The conservative valve events also mean a very unsatisfying powerband that encourages short shifting and explains our engine's reluctance to make power with bolt-on mods.

Our stock cams had a ridiculously low intake valve lift of 0.283 inches with a very small duration of 207 degrees. The exhaust valve lift was an even smaller 0.277 inches with 229 degrees of duration. This is the least lift we've ever seen on any automotive engine. The cam's lobe centers are spread so far apart there's no overlap at all. As a comparison, the intake cam in a stock Nissan SR20DE has 41 degrees more intake duration, and 0.112 inches more lift. The SR20 also has 17 degrees of valve overlap.

The tech wizards at Crane recommended we run the second of their three available cam grinds, P/N CHR-250-2SR-8. This cam, which is supposed to make gains from 1500 to 6800 rpm, has considerably better lift and duration numbers than stock. The intake lift was a much higher 0.355 inches with a duration of 250 degrees. On the exhaust side, the lift was 0.315 inches with a duration of 250 degrees. The Crane cam has a tighter lobe separation angle of 108 degrees. Although these numbers are much bigger than stock, they pale in comparison to your typical high-performance grind.

We noted that the SR20 and the Neon engine are both 2000cc with similar bore and stroke. However, the Neon cylinder head has much smaller ports, especially on the exhaust side. The angle of the Neon's exhaust ports is also rather flat, with the port turning a tight radius inside the head. Usually ports of this nature do not flow well at high lift, the flow tending to stall as maximum lift is approached. In this case, opening the valve higher than the stall point usually does not help power and is much harder on the valvetrain. A big cam on a stock head would simply narrow the powerband and make the idle rough without giving much of a peak power gain.

The SOHC Neon also has a rather poorly conceived rocker arm/cam follower design. The heavy hydraulic lash adjuster is built into the valve end of the rocker arm where it cycles at the valve's maximum stroke with each revolution. This is the worst possible place such a device could be installed. On most typical overhead cam engines, the hydraulic lash adjuster is stationary. The Neon's design probably necessitates overly heavy valve springs and increased friction that robs both power and fuel economy. Why the engineers chose to place the adjuster where they did is beyond us.

To help control the gyrations of the valvetrain at high rpm, we replaced the stock valve springs and retainers with Crane's recommended valve springs and lightweight titanium retainers. Though not mandatory for use with this cam, the heavy rocker arms of this engine make the choice an obvious one.

The Neon uses shaft-mounted rocker arms. Note that the hydraulic lash adjuster (HLA) is in the worst possible place where it has the most inertia to cause valve float. It's apparent that this heavy valvetrain was not designed for high revs.
The Neon uses shaft-mounted rocker arms. Note that the hydraulic lash adjuster (HLA) is in
The Crane cam, titanium retainers and higher tension valve springs are at the top of the photo; the stock Neon cam is on the bottom. The copper plating in-between the cam lobes on the Crane cam is there to help seal porosity and prevent casting sand and other debris from contaminating the engine. This is a nice touch unique to Crane.
The Crane cam, titanium retainers and higher tension valve springs are at the top of the p
Looking at the cam lobes closely, it's easy to see that the lobe profile on the Crane cam is more radical with more lift, duration and area under the lift curve.
Looking at the cam lobes closely, it's easy to see that the lobe profile on the Crane cam