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Slightly more than a year ago, we took a detailed look at Jesel’s innovative high tech camshaft belt drive system. In that article, we explained how Jesel’s belt drive helps to eliminate valve train harmonics, promote stable cam timing and simultaneously improve engine power and reliability. It’s a great piece and it’s been well proven in all sorts of motorsports ranging from drag racing to circle track to endurance competition. This time around, we’ll look at the belt drive setup from the installation perspective. Jesel’s belt drive package isn’t difficult to install, but there are some considerable differences when you compare the installation to a conventional timing chain.
When installing a belt drive on any application, the first thing you have to ascertain is the fit of the belt drive timing chain valley cover plate. Due to tolerances in block manufacturing, there can be some differences between respective components. Case-in-point is the Chevy Gen 6 Bow Tie big block shown in the accompanying photos. GM changed up their casting over the years and there are several points of interference. They have to be resolved, and we’ll show you how to accomplish that right here in the first segment of our series (more in the accompanying photos).
Another big consideration before you go any further is if the block in question has been line bored. If that’s the case, Jesel notes that you may encounter misalignment between the crankshaft seal and the crankshaft snout. If that’s the case, Jesel recommends you enlarge the dowel pin holes in the cast valley cover and loosely install the cover bolts prior to driving on the lower pulley. Jesel states this procedure will insure that the crank seal is centered on the crankshaft snout.
Finally, you should also check for any potential inference between the belt drive and the water pump as well as the harmonic damper. For an application such as a big block Chevy with a conventional long water pump and something like an 8-inch damper, you’ll seldom encounter a clearance issue. On a short water pump application, you might have to clearance the water pump to fit the belt drive.
Following is series of photos that show how to clearance the cylinder block to accept the belt drive timing chain valley plate. The process isn’t difficult, but you have to go slow with iron removal (it’s easy to remove too much!). Check it out:
Here’s the face of a new Chevy Gen 6 Bow Tie big block. Over time, the cylinder block castings have been revised and there can be some fit interference issues with the Jesel timing valley cover plate.
Here’s one area of interference. The boss surrounding the cover plate threads in this location interferes with the fit of the cover. There’s a similar boss that requires trimming on the opposite side of the block. By the way, the block must be clearanced – not the cover plate.
As you can see, the backside of the timing cover has indentations for the respective bosses. The trouble is, Chevy’s latest boss is larger than the indentations. Each boss has to be trimmed.
The block is covered and taped as shown here. The idea is to minimize the amount of iron shavings and debris that enter the cylinder block. Additionally, the block is marked where it has be clearanced.
Iron removal is easily accomplished with a small hand held die grinder fitted with a tapered burr combination such as this. It works well, but be cautious: You can remove quite a bit of iron in a short period of time with an air powered die grinder.
Here’s what the valley looks like after trimming. Not a lot of material has to be removed – just enough to fit the Jesel valley plate. FYI, this testing fitting and checking clearances applies to all engine blocks, not just Gen 6 big blocks. Double check the fit on all applications.
Once the block is clearanced and the fit of the Jesel valley cover is double checked, the block can be washed. A bath in a mix of dish detergent and hot water works well.
While you’re at it, you should brush out the oil galleries.
After the block is rinsed clean, dry with compressed air and lint-free paper towels soaked in oil.
