The Jesel beltdrive system...
The Jesel beltdrive system has been around a long time and is used by a lot of professional engine builders. The exposed belt allows quick cam changes and easy adjustment of the cam timing.
Jesel does have a rocker arm set for the Indy 440-1 head, which is a close cousin to the Indy EZ head, so we purchased the 440-1 kit and began our modifications. The existing rocker stands on the head have to be machined away in order to mount the Jesel shaft stand. This machining requires precision equipment like a milling machine since the hole centers need to be properly located. The Jesel kit didn't come with any machining instructions, but after a few phone calls to Jesel, an engineer faxed us the necessary information and we were off to the machine shop with our blueprints in hand.
Once we had the new rocker arms mounted on our heads, we quickly noticed that the high offset 440-1 intake rocker arm wasn't really a good match for our EZ head, since it moved the pushrod over too much. We could have re-machined the head for extra pushrod clearance, but we decided instead to work with Jesel on getting a set of standard-offset intake rocker arms. The standard-offset rocker arms eliminated our pushrod clearance issues but caused another problem, which we didn't discover until it cropped up during dyno testing.
In addition to the Jesel rocker arms, we also installed a Jesel beltdrive for the camshaft. A beltdrive has a number of advantages over a chain drive, including lower harmonics, less friction, easy adjustments, and higher strength. We especially like the fact that the camshaft can be changed without scraping the timing chain cover gasket or disturbing the oil pan gasket. Also, the camshaft end thrust is quickly adjusted with shims rather than machining a cam button. The Jesel beltdrive system has been around a number of years, and is fairly well proven. Consequently, they tend to bolt on without much fuss or hassle. In our case, we just had to hone out the lower gear in order to get a better fit onto our crankshaft, and then everything slid right on.
BeltDrive Distributor and Ripple Effects
Camshaft thrust is easily...
Camshaft thrust is easily adjusted by changing shims behind the bearing retainer. We set up this motor with .007-inch of thrust clearance.
We decided to install a beltdriven distributor on this motor to free up some clearance around the valve cover, and that triggered a series of changes that required several weeks of machine shop time to resolve.
Typically, the location of the big-block Mopar distributor is an advantage since it is up front on the engine and angled over towards the passenger fender. But when you start to use taller aftermarket cylinder heads with large valve covers and a large distributor with big fat spark plug wires, everything starts to run into each other. We eventually got tired of wrestling with the Indy valve covers every time we had to pull the distributor, so we purchased a beltdriven distributor from Jesel. Since we were using a crank trigger ignition, we didn't need any type of advance mechanism, and the Jesel distributor is small, lightweight, and has a big cap to reduce spark scatter.
We used an MSD crank trigger...
We used an MSD crank trigger for the ignition system since it provides rock-steady timing. The bracket that came with the MSD kit didn't fit with the Jesel beltdrive so we fabricated a custom bracket. While we were at it we included an adjustable TDC pointer.
The first issue we ran into is that the mounting bracket that comes with the Jesel distributor didn't fit our motor at all. Once we fixed that situation, we discovered that the Jesel distributor occupied the same space as the thermostat housing on the water pump. We considered making some long spacers to move the water pump housing forward on the engine, but then someone showed us the new reverse flow water pump from Meziere. This water pump has an outlet on each side of the block that points forward rather than a central outlet pointed upwards. Without the central thermostat housing, we had plenty of space for the beltdriven distributor. The lack of a thermostat didn't bother us since one isn't required on the dyno anyway, but if a person was going to use this water pump in a car, they would need to fabricate some sort of thermostat setup.
Once we sorted out how to mount the Jesel distributor, we went to work on the crank-trigger bracket. The bracket kit that came with the MSD kit didn't align properly with our combination of ATI damper and Jesel beltdrive, so we headed back to the machine shop. Eventually, we developed a slick little bracket that mounted the crank trigger in the correct location and provided a mount for a TDC pointer.