In the 1950s and early 1960s, Buick, a division of General Motors, manufactured large automobiles that were powered almost exclusively by eight-cylinder engines. That changed in 1961 with the mid-sized Buick Special and Skylark models, which came standard with a new small-displacement 198 ci V6 engine. Buick sold the rights of its V6 to Kaiser-Frazer in 1967 to be used in Jeep models. In the mid 1970s, Buick found itself needing a small, lightweight engine to power its smaller vehicles again and bought the V6 back from American Motors, then-owner of Jeep. The engine was reworked to displace 231 cubic inches and was used in Buick cars for many years after. When assembling 231 V6 components, the correct tightness of the bolts must be achieved by checking them with a torque wrench.
The air conditioning compressor bracket nuts should be torqued to 74 foot-pounds, the compressor lower bolt to 59 foot-pounds and the compressor upper bolt to 36 foot-pounds. The alternator bracket bolts should be tightened to 36 foot-pounds. The vibration damper bolt at the front of the engine needs to be tightened to 111 foot-pounds. The long water pump retaining bolts should be tightened to 15 foot-pounds, while the short bolts need to be tightened to 11 foot-pounds. The spark plugs should be tightened to 15 foot-pounds. The exhaust manifold bolts should be torqued to 13 foot-pounds. The cylinder head bolts should be tightened to 37 foot-pounds. The water pump pulley retaining bolts need to be tightened to 116 inch-pounds.
The balance shaft sprocket retaining bolts should be tightened to 16 foot-pounds. The valve lifter guides should be tightened to 22 foot-pounds. The rocker arms need to be tightened to 11 foot-pounds. The connecting rod bolts require 20 foot-pounds of torque. The timing chain or belt sprockets need to be tightened to 74 foot-pounds.
The rear bell housing cover retaining bolts should be tightened to 5 foot-pounds. The valve covers require 89 inch-pounds of tightness. The timing chain cover needs to be tightened to 15 foot-pounds. The oil pump cover should be tightened to 89 inch-pounds. The oil pan retaining bolts should be torqued to 125 inch-pounds.
