Corvette Engine Build - The Power Principal

An Economical 383 Engine Build Anyone Can Do

Chris Petris Dec 8, 2009 0 Comment(s)
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The new Clevite 77 H-series bearings have a coating that we lightly scrub off with a worn Scotch-Brite pad. Clevite 77 H-series bearings are used because of their chamfer on the outside edges of the bearing shell. This allows clearance for the Eagle crankshaft's large radius at the main and rod bearing journals. The large radius prevents cracking at high rpm. We could use P-series bearings, but we would have to chamfer the bearings ourselves. Plus the H-series are race bearings that can take a pounding from nitrous if necessary.

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Finally, we can apply our Royal Purple synthetic assembly lube to the main bearings and lay the crankshaft in place. Of course, we washed the new Eagle crank in mineral spirits solvent and used shop air to blow it dry. Any grit left behind will imbed itself in the bearing and chew away at the crank so keep everything clean. Remember, all parts should be cleaned before installation, even new parts in plastic bags.

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Before we torque the main bearing caps, a dead blow urethane hammer is used to seat the crankshaft against the rear main thrust bearing. The crank is thumped from the rear and front to position the rear main cap. When we checked the clearance before and after the thumping, the clearance changed from 0.002 to 0.0045. If we neglected to position the main cap, only half of the rear thrust bearing would take the load applied by the clutch when we shift the five-speed Tremec transmission.

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It would be nice to show every step of the way, but since we can't, the four-bolt main bearing caps are torqued to specification after we apply light oil to the main-cap bolt threads. If we put the main caps back in the correct location, the crankshaft should spin easily. New engine blocks and OE engine blocks do not have the main or connecting rod cap position marked, so beware! If the caps are not put back in their respective positions, the block or connecting rods will require line boring because the crank won't turn.

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Next, the pistons can be installed with our 4.030-bore tapered sleeve. A liberal coating of Royal Purple 10W30 oil was applied to the piston and cylinder to ease piston installation and prevent dry start-up. Before the piston is installed in the sleeve for cylinder installation, the ring endgaps are positioned 120-degrees apart to lessen compression gas loss that blows into the crankcase. Remember, being conscientious and repetitive makes for a reliable engine. It may sound boring, but it is the only way to know the job is done right.

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Our Clevite 77 crankshaft protectors are placed on the connecting-rods' bolts and a coating of Royal Purple Synthetic assembly lube is applied to the rod bearing before the piston is seated on the crankshaft. Connecting rods have a bearing lock recess to prevent bearing spin. The lock recesses should always face the outside edge of the block. Connecting-rod beams are offset on the bearing saddle with the connecting rods sitting closer together at the center of each crank throw.


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