October '17

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OCTOBER 2017 PRECISION ENGINE 9 PRECISION ENGINE MOTOR MOUNTS & DOWELS A pair of Moroso 0.620-inch-diameter steel dowel pins that featured a chamfer at both ends were installed and fully seated in the rear of the block at a press fit of about 0.0018 inches. The World Products Motown II LS block features both SBC and LS motor mount threaded holes, making it convenient to install the block to either a vehicle that originally had a Gen I small-block or to a vehicle that originally had an LS engine. Note that all of the block's motor mount holes are threaded for 3/8-16 bolts (for both SBC and LS motor mount attachment). Whether securing the block to motor mounts, to a cradle or dolly, or to a dyno stand, all motor mount holes require 3/8-16 bolts. PRE-OILING Prior to the dyno trip, I pre-oiled the engine while it was still mounted to our Goodson engine cart. I first removed all spark plugs to ease crank rotation. I filled my Goodson EPL-120 aluminum oil pressurizing tank with oil, then pressurized the tank with 80 psi of compressed air. The tank hose was connected to the block's 1/4-NPT sender port and we then opened the pressure tank's valve. This forced oil throughout the oil passages, while I slowly rotated the crankshaft twice (360 degrees) to ensure oil delivery to all bearing hole feed locations. This was followed with a driver and drill to run the Mel- ling oil pump, verifying pump operation and oil delivery. After pre-oiling, I drained the oil pan sump, then added 6 quarts and 20 ounces of 5W-30 Pennzoil mineral oil, plus 12 ounces of COMP ZDDP break-in high-pressure lube in order to provide the total 7 quarts of sump capacity. CORRECTION: In Part 1 of this series, I inadvertently listed the use of a Chevy 350 two-piece rear main seal. This application calls for a thicker 400 small-block rear seal. MIKE MAVRIGIAN owns and operates Birchwood Automo- tive in Creston, Ohio, where he builds custom engines, street rods and performs vehicle restorations. He has written thousands of technical articles, as well as nine books on automotive technology during the past 30 years. Mike can be reached at 330-435-6347 or Visit Birchwood's website at Although Ross Racing specializes in a variety of engines with an emphasis on Pontiac, Buick and Olds, the shop didn't have any LS headers in stock, so we supplied a set of Hooker ceramic-coated headers for our dyno run. The ceramic coating definitely reduced the loss of radiant heat and cooled surprisingly fast as compared to bare or painted pipes. Prior to final pulls, the engine was run at high idle to seat the rings, followed by cautious increases in rpm.

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