THE SHOP

January '21

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50 THE SHOP JANUARY 2021 Another go-round building a tried- and-true Gen 1 small-block Chevy. Back to Basics By Mike Mavrigian Part III EDITOR'S NOTE: This is the third article in a multi-part series detailing the build of a 422-ci small-block Chevrolet Gen 1 engine. Part I appeared in the July 2020 issue of THE SHOP magazine and Part II in the October 2020 issue. CRANK BALANCER INSTALLATION It's critical to install a balancer by drawing it onto the crank snout slowly and evenly. The fit will involve a slight interference of 0.001- to 0.003-inch, depending on the manufacturer and application. For this build, I chose a Fluidampr 6.25-inch balancer that features timing marks. Our SCAT crank snout OD mea- sured 1.2465 inches, and our Fluidampr bore measured 1.2445 inches, providing us with a very nice 0.002-inch press fit. Always measure, as it's possible that a manufacturer's crank snout and/or bal- ancer bore may provide a variable that will result in an excessive interference fit. If the fit is too tight, many builders tend to gently hone the balancer bore to achieve the specified fit— although balancer makers advise not to modify. Once clearances have been determined, coat the crank snout and the balancer bore with a high-quality anti-seize com- pound. Align the balancer to the crank snout, initially engaging the key. Use a balancer installation tool such as the Moroso 61743 puller/installer kit. Install the appropriate-size threaded adapter to the tool's threaded mandrel. In the case of a small-block Chevy, this is the adapter that features a 7/16-20 thread. Apply oil or assembly lube to the adapter threads before assembly to pre- vent galling. Also lube the mandrel's threads and install the pusher nut onto the threaded mandrel. Insert the mandrel into the pusher plate with the flat side of the plate facing you. Screw the mandrel into the crank snout with the 7/16-inch adapter engaging the crank snout threads. The plate features a built-in bearing that the driver nut seats against. While holding the hex at the exposed end of the mandrel steady using a 5/8-inch wrench, use a 1-1/16 open-end wrench to turn the driver nut clockwise. This pushes the balancer onto the crank snout. Make sure that the balancer is square to the snout. Avoid any angles that would result in galling the crank snout. Draw the balancer fully into place until it dead-stops against the crank gear or, in this case, the Jesel belt-drive crank pulley. Remove the tool. If the 7/16-inch adapter happens to remain in the crank snout, it is easily removed using a flat-blade screwdriver. PISTON/ROD INSTALLATION The rings supplied with our ICON pistons required a file-fit. Slightly oversized rings allow you to file-fit to achieve exactly the desired end-gap. Their specification calls for a gap of bore diameter x 0.0045-inch. In our case, this calls for a gap of 0.0187-inch. Using a Summit Racing ring filer equipped with a diamond wheel, I carefully filed all top and second rings to achieve an end gap of a snug 0.019-inch. Once the rings were file-fit, the filed edges were carefully deburred using a small, fine flat file and then thoroughly cleaned. When checking ring end gap, insert the ring into a clean bore and square the ring at a depth of about 3/4 to 1 inch, using a ring-squaring tool that pushes the ring down evenly. The entire ring circumference must be set at an equal depth in the cylinder in order to obtain an accurate gap measurement. JANUARY 2021 Ed Iskenderian p.58 Engine Products p.62 This closeup shows the timing mark on the cam pulley aligned with the zero mark on the spider. Each mark on the spider represents 2 degrees, allowing builders to advance or retard as needed. 50 THE SHOP JANUARY 2021

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