The Choate Self-Oiling Integrated Valve Covers were designed out of necessity. Anyone with experience with the 6.4 understands this issue all too well. The 6.4 was coming off the heels of the 6.0 platform that used a “HEUI” fueling platform. This “hydraulically actuated electronically controlled unit” means that the injector, upon firing, emits a stream of oil as it is exhausted. This extra oil allows for lubrication on the top of the rocker arm conversely. This allows the 6.0 rocker to last many miles without failure. However, upon the arrival of the 6.4, International changed to the “High-Pressure Common Rail” design. This was to achieve the injection pressures that were needed to meet the emission standards set at that time. In doing so this did away with the oil that was so desperately needed for the rockers. And ended up in many catastrophic failures.
Studies were done to determine how long the oil would take to reach the rocker arm upon start-up. This obviously will vary based on the pour factor of the oil, viscosity, and ambient temperature. The study was done using a 15w40 diesel engine oil ASTM D-97 pour factor -15c with a cetostoke of 12. It was noted that based on the location of the rocker arm to the oil galley, it took up to 3-5 minutes before lubrication reached the rocker arms at 750rpms@60 psi oil pressure.
That in and of itself should alarm any 6.4 owners!
The wear on the rocker arm creates a reactionary chain of events to take place that end in the cataclysmic failure of the engine. Once the rocker arm begins to wear down, not only is metal introduced into the engine, and loss of valve lift, performance, and fuel mileage; but most importantly the geometry between the valve bridge and the hydraulic lifter is compromised. This leads to incorrect preload of the lifter. And creates a shockwave upon each rotation of the camshaft as the valve is opened. This applied force into the lifter is transferred into the smallest bearing in the engine, the needle bearing of the lifter. This in turn leads to premature lifter failure, which damages the lobe on the camshaft, which is installed by way of the rear of the engine. So this means that the engine must be removed and all the contamination from the failed parts must be cleaned. Which requires entire engine disassembly. At this point, the owner is going to be buying an engine.
The Choate valve cover addresses this issue by using an oil galley that is machined into the valve cover itself. This is fed off the oil cooler housing that feeds the turbo cartridge. The oil is then regulated down thru an orifice that restricts the oil to .343 GPM @ 40 psi. It then enters the valve cover and is allowed to go thru the oil galley to each spray jet that is machined and installed directly over each rocker arm. Consequently providing the oil to the rockers, just milliseconds upon startup. This eliminates the wear of the rocker arms and provides two other purposes for the engine.
- A study was done on the same vehicle at the same operating temperatures, with all things equal. With the factory cover on, the reading taken was 98.8 decibels. Upon installing the new Choate Valve covers the same test was done, this time yielding a decrease in noise at 86.9
- The second byproduct of the cover is that it allows for noise reduction in the cab. This means no more having to turn the engine off at a drive-thru.
- Thirdly, the gains also provide heat dissipation via the aluminum cover that reacts as a heat sink to the oil. These results vary and have been seen to lower oil temperatures by five degrees.
Tests were done to ensure that the deviation of oil would not cause any adverse conditions in the oiling system. Pressures were tested before and after the Choate covers were installed and found to not alter at any time over factory set up.