For about the past three years, MM&FF has tackled a lot of projects using Three-Valve engines. We have made ridiculous power thanks to the latest forced induction components, as well as having some fun with the giggle gas stuff. Our staff has also beat the latest mod motor to death on chassis dynos, dragstrips, road courses, and even engine dynos, to show what the aftermarket has to offer. In reviewing some of the previous stories on the engine, we noticed a trend of working mostly with forced induction or simple bolt-ons. This month, we ventured to Livernois Motorsports and tackled a naturally aspirated buildup. We decided to swap the heads and camshafts on a stock engine, which was bolted up to Livernois' in-house engine dyno.
In stock trim, the Three-Valve engine made 313 hp and 314 lb-ft of torque. Our test engine was fitted with Kooks dyno headers, XFI stand-alone EFI, no engine accessories (except for a water pump), and no airbox or MAF sensor. VCT was locked out due to the use of the aftermarket EFI.
The latest modular engine features some interesting technology that addresses some issues of the modular line. First and foremost, the small cubes definitely hurt overall torque output. To solve the problem, without hurting high rpm power production, Ford turned to a neat trick that other manufacturers utilized in their small-sized engine packages. It's called Variable Camshaft Timing. Essentially by adjusting the cam timing, the power curve can be shifted up or down. In the past, once you set cam timing you were stuck with its results, but not anymore. The Three-Valve engines have the ability to move the camshafts while the engine is operating.
In stock trim, Ford sets up Three-Valve engines with 7-degrees advance and then retards the camshafts as the rpm powerband moves north. The computer is capable of shifting the camshaft timing as much as 60 degrees (in relation to the crankshaft). That puts camshaft timing at a total of negative 2 degrees (a total of 9 degrees retard from the initial setup). To accomplish this task, Ford uses a series of channels and reservoirs in the camshaft sprocket in order to physically move the camshaft while the engine is running. The system is a really basic concept where computer controlled valves (one for each cam) regulates the oil flowing in and through the sprocket. The rule of thumb with camshaft timing is that advancing the cam shifts the powerband to the lower rpm levels. Retarding the cam timing moves the powerband higher. Combine the new camshaft movements with a killer set of Three-Valve heads, and Ford built a modular engine that out performs the previous generation of Two-Valve mod motors and even some of the naturally aspirated Four-Valve cars.
The stock heads were removed and discarded. We reused the stock camshafts for our first test, just to see what the Livernois-ported heads would gain over stock.
Back in the Aug. '08 issue of MM&FF we explored the concept of limiting variable camshaft timing (VCT) in Three-Valve modular engines ("Lockdown," pg. 128). In the article, we tested Comp Cams' Phaser Limiters, which restrict the camshafts to just 20-degrees of movement. Limiting the camshafts works well, and we picked up a lot of power with our test subject, a 300ci mod motor. As with everything in this hobby, there are many different ways to get results, and Livernois Motorsports has its own version of locking down the VCT. Its engine shop has developed special inserts that completely lockout the cam timing, making it a fixed entity.
Livernois has vast experience with these engines and has chosen to completely lockout the VCT using inserts in the cam sprockets. Why would they decide to do so when it seems the system works so well, giving these Three-Valve engines both low-end grunt and top-end charge? "The main reason we prefer the full lockout method is that currently we have seen far too many issues and failures to feel comfortable with the VCT system functioning. We have seen completely stock VCT systems have issues with cam phaser failures. This is why we suggest to lockout the phaser," says head Livernois engine builder Mike Schropp.