Kevin's Engine Overhaul Project

Engine Assembly: Crank, rods, pistons

Although not shown below, prior to final assembly all main and rod bearing clearances were checked with plastigage. All rod bearing clearances were 0.015-0.020" All main bearing clearances were 0.025". Originally, the main bearing clearances were too tight, measuring less than 0.0010". Although Packard specifies as small as 0.0005", Craig considered this much too tight and sent the crankshaft, block and main bearings back to the machine shop to gain more clearance. This was accomplished by line honing the block and grinding & polishing the crank slightly. The moral of the story: ALWAYS check these bearing clearances and do NOT assemble the engine if they are not within spec.

The install ring gaps for ALL rings were checked by feeler gauge in the cylinder in which the particular ring was to be installed. The ring was "squared up" in the bore by using a piston inserted upside down about 2" down in the bore.

With this inexpensive (about $30 from Summit Racing) ring gap grinder, Kevin carefully removes a little material at a time. 2nd rings were gapped at 0.015" and top rings were gapped at 0.020" None of the oil rails needed grinding, being at least 0.025" out of the box.

All the rods are assembled on the new Egge pistons using the pins and clips supplied. All the pistons are interchangeable rod-to-rod, but the "notch" in the piston top points to the front of the engine. MAKE SURE that the oil squirt hole on one side of each rod will be pointing to the other cylinder bank!

With the piston rings installed on the piston (marked top installed "up" and gaps 90-deg apart) this piston ring installer tool was used to compress the rings smaller than the bore and then the piston was tapped into the bore. Note the "waffle" ring design and over-center tightner. This installer WORKS! The typical plain band type installer did NOT and should be thrown away as less than useless!

While Craig taps the piston/rings/rod assembly down into the bore, Kevin carefully guides the rubber hose-covered rod bolt by the crank pin. Once the rod & upper bearing insert is seated against the crank pin, the rubber hose is removed and the rod cap and bearing insert are pushed on and the nuts snugged down finger tight.

Kevin finds that torquing the rod cap nuts are easier than the mains. Done by adjacent rods on an individual crank pin, the nuts were torqued first to 20lb-ft, then to 43lb-ft.

Crankshaft, rods, pistons, rings and bearings are now installed. Put a big plastic bag over it because "it's Miller time!"


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