The Life and Times of the Buick V6 |
Ken Mosher - kenmosher@turbo-link.com
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The venerable Buick 3.8 V6 has had a long and fairly illustrious career, powering many Buicks, and other GM vehicles over the past 30 years. The original design for the V6 started in the early 60s when Buick created a V6 based on the all aluminum 215 V8. The very first "Fireball" V6 displaced a whopping 198 cubic inches and shared tooling with the 215 aluminum V8 in 1962. In late 1963, the bore was increased to be the same as the 300 V8, which made displacement 225 cubic inches, where it stayed until 1967. Since the V6 had the same bore as the 1966 340 V8 it could be produced on the same assembly line. This made it cheap and easy to produce for the "compact" cars in GM's car lines. The demand for the V6 was never very great and the design resulted in an uneven firing order that produced a rough idling engine, so the design was sold to Jeep in 1967.
In the 70s, with the advent of the gas crisis and the demand for a versatile, lightweight, and inexpensive engine, Buick bought the design back from Jeep in 1974. The little V6 was reworked so that it could be made on the same assembly line as the Buick 350, which entailed making the bore 3.800". Using this bore size, it could share pistons and other parts with the V6. This engine retained the original designs "odd-fire" design.
In 1977, Buick redesigned the firing order to make it a smoother running engine by revising the crank throws. This was a mid-year change, so some odd-fire and some even-fire V6s were made during 1977. The new even-fire engine still retained the same bore spacing as the odd-fire version, so the bores were no longer centered over the rods and the engine had to be under balanced and soft motor mounts were used. The balancing took care of the vertical component of the vibrations and the motor mounts took care of the horizontal component.
Several variations of the 231" V6 were made over the years, including the 3.0 liter in some of the early 80s front wheel drive cars, the 4.1 liter used in some of the larger rear wheel drive cars, and of course, the turbo 3.8 variations used in the various Sport Coupes, turbo Regals, some early '80-81 Monte Carlos, and some of the Riviera's.
This article will concentrate on the 3.8 versions, since that's more relevant to those of us with the turbo cars. The basic design for the engine that went into the turbo Regals really didn't change much from late 1977 until 1987. The blocks had slight revisions up until 1986-87, mainly to increase oiling and to revise the deck heights to allow the use of thicker composition head gaskets. One of the biggest changes was in 1985, when the oil pans went to 20 bolt oil pans instead of 14 bolt oil pans.
All in all, there were a lot of the 3.8s produced, due to it's many virtues. The availability of basic mechanical parts is still very good and many specialty parts for the GN/turbo Regal turn up as new parts for other car models with the 3800 (a redesigned 3.8), such as the Reatta. Below is a history of the V6, followed by a chart cross referencing some of the blocks/cranks/heads used over the years that was derived from the March 1994 issue of Automotive Rebuilder.
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
Block, Head, Crank - Part Numbers
Application
Year
Block
Head
Crank
1975-76
1249432
.
.
1977
1254083
1237722
1257125
.
.
1255862
.
.
.
.
1232438
.
.
1978
1261438
1257661
1260877
.
.
1261787
1257051
2551229
.
.
25505554
.
.
.
1261438
1257661
Rolled Fillets
1979
1261787
1262098
25500229
.
.
25505554
25504443
.
.
25514290
25504443
.
.
.
25505554
25504443
Rolled Fillets
1980-81
25506818
25505900
See 1978
.
.
25506293
.
.
25506818
25505900
See 1978
.
.
25506293
.
.
25506818
25505900
See 1978
.
25506485
25506293
.
1982
25506818
25510191
See 1978
.
.
.
25514290
.
.
25506818
25510191
See 1978
.
.
.
25514290
.
.
25506481
25510191
See 1978
.
.
25524289
.
.
1983
25524289
25518445
See 1978
25506397
.
.
.
25524289
25518445
See 1978
.
25524289
25518445
See 1978
1984
25524290
25518445
See 1978
.
.
25528601
.
.
.
.
25520040
.
.
.
25520040
25518445
See 1978
.
.
25518603
.
.
.
25520040
25518445
See 1978
.
.
25520042
.
.
.
.
25528603
.
.
1985
25524140
25518445
See 1978
.
.
25520329
.
.
.
25520329
25518445
See 1978
.
25520231
25518445
See 1978
.
25520043
25518445
25514267
1986
25526109
25518445
See 1978
.
25526109
25518445
See 1978
.
25526110
25524248
25514267
.
25526111
25524248
25514267
1987
25526109
25518445
See 1978
.
25526109
25518445
See 1978
.
25526110
25524248
25514267
.
.
25526111
25529889
25527515
1988
25528801
25527515
25514267
.
25532617
25529723
25530502
.
.
.
25522646
.
1989
25528801
25527515
25514267
.
25526109
25536702
25511229
1990
25531617
25534250
25530502
.
.
.
25532646
.
.
25532674
25534250
25534737
1968-1972
3877178
3895052
.
.
.
3850817
3927763
.
4.1L RWD
1973-1976
366855
3962084
.
.
.
348675
14002012
.
.
.
328575
370696
.
.
.
743483
355795
.
.
.
358675
377133
.
4.1L RWD
1980-1984
25506484
25504443
.
.
.
25505553
25505900
.
.
.
25514291
25506293
.
.
.
.
25518445
.
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