The following items are things we learned over the years that can make a big difference in the quality/reliability of a rebuild. No checklist is ever perfect, but we hope this list will help you to apply our experience to your rebuild – so that you may not have to do it again.
1) _____Check all castings for rust and scale removal.
2) _____If a steel 1/4″ pipe plug (usually Allen-headed) has been installed in the center of the rear wall of the valve chamber, remove it and replace it with a brass or stainless plug.
3) _____Check the floor of the cooling water jacket in late model heads, directly below the thermostat housing opening for the presence of a small pin hole (in a location that is just slightly under the edge of the head gasket). These holes can be repaired by drilling and tapping for a 1/16″ pipe plug.
4) _____Inspect the lower 1″ to 2″ of each cylinder bore, especially along the cam shaft and water jacket sides, for any discoloration that would indicate extreme thinness and possible pin hole leaks. Probe any discoloration with an ice pick.
5) _____Check for maximum gap of .008″ (total) between head to block, and manifold to block mating surfaces.
6) _____Oil passage ways in block thoroughly cleaned.
7) _____Oil passage ways in crankshaft thoroughly cleaned.
8) Cam bearings installed with oil holes aligned with holes in block.
9) _____Inspect threads within stud holes in block and dry-run studs to check for fit. If any studs are quite lose, replace with an MMI 7/16” repair stud.
10) _____Inspect inside of thermostat housing for proper configuration.
11 _____ If there was evidence of water intrusion on the engine, particularly in the reversing gear assembly, check the small 1/8” roll pin securing the cast iron oil pump drive gear to the shaft. If you see any sign of rust in the area of the roll pin, replace it. They are available at any local hardware store for about 10 cents.
Items to be checked prior to installing oil pan:
1) _____Three oil plugs installed; one at each end of the cam shaft and one directly below the oil pressure regulating valve. There are a total of 6 oil plugs; the other three are accessible on the outside of the block on the carburetor side.
2) _____Timing marks on crankshaft and cam shaft gears aligned.
3) _____Two set screws installed to retain idler gear spindle.
4) _____Check max ring end-gap of .018″ on at least 2 cylinder bores.
5) _____Check max of .004″ between ring and ring grooves in pistons.
6) _____Pistons installed with number one toward flywheel.
7) _____Pistons installed with arrows pointing toward reversing gear, or with slots in piston skirts pointing away from cam shaft.
8) _____Rods installed with numbers pointing toward cam shaft.
9) _____Alignment tabs on rod bearings placed carefully in their respective recesses in rods and rod bearing caps. To be sure the tabs stay aligned during final assembly of the piston, make sure the large rod end has a small amount of side to side end play on the crank journal.
10) _____Each rod rechecked for side play after installing rod bearings.
11) _____Oil strainer installed with proper slope along bottom of oil pan, and with some clearance so as to not press on the bottom of oil pan (spring between screen and 1/8″ street el should be almost fully compressed).
Items to check before installing head:
1) _____Proper roughness on block deck and head mating surface. (Scribe lines using an ice pick or similar tool.)
2) _____Seal all studs into block using Lock Tite “Studlocker” sealer.
Items to be checked before installing the aft housing:
1) _____Make sure that the shifting lever shaft rotates freely within the aft housing.
2) _____ Run feeler gauge under oil strainer to be sure that the screen is not pressing on bottom of oil pan (minimum of .005″).
3) _____Install small pilot bearing in rear of crankshaft.
4) _____Check that idler gear is installed properly and that a cotter pin is installed in the castle nut on early model engines.
5) _____Clean oil collection groove and return holes in flywheel housing.
1) _____All studs extending through head nuts the same distance.
2) _____Clean up all extra sealer.
3) Use the bolts shown below on the following components:
_____Oil pan 5/16″ x 7/8″
_____Rear oil seal housing 5/16″ x 1″
_____Electric fuel pump bracket 5/16″ x 3/4″
_____Accessory drive bolts 3/8″ x 3 3/4″
_____Fuel pump 5/16″ x 7/8″
4) _____Use copper or brass flat washers under water jacket side plate bolts, under the reversing gear cover plate, and under the lower three bolts in the rear oil seal housing.
5) _____Grind bottom of sheet metal flywheel cover flush with housing.
6) _____Trim the end of the upper left water jacket side plate stud (if installed) so that it clears distributor cap on late model engines.
7) _____On the latest engines, the surface of the block around the water jacket side plate opening sometimes is not always straight if you check with a straight edge. If this is the case with your engine, put a slight bow in the valve cover plate so it presses in against the gasket on each end.