NOTE: this page is a local copy of the page from http://www.gnttype.org/general/v6hist.html

The Life and Times of the Buick V6
The Little Engine That Could!

by Ken Mosher, Midlands Chapter Member GSCA

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 V8. In 1963, the bore was increased to be the same as the 340 V8, which made displacement 225 cubic inches, where it stayed until 1967. Since the V6 had the same bore as the 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 '78-81 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

• Odd fire design in early model year
• Even fire design produced late in model year
• Cylinder heads revised with new exhaust ports and cast rocker stands

• ---

1978

• Harmonic balancer bolt changed from 5/8" to 3/4" (both versions were produced this year)

1979

• Intake ports revised for better breathing

1980

• Oil sump and feed passages enlarged from 0.500" to 0.625"

1981

• New connecting rods with heavy section cap (they have 2 dots with #763 on the side of the rod)
• New harmonic balancer and flywheel for different balance due to new connecting rods
• Block revised for rod cap clearance

1982

• M10x1.5 metric for accessory mounting holes on heads
• Boss on the rear of block for Knock Sensor

1983

• Head revised to remove iron at outside edge for valve cover baffle clearance
• New intake valve guide seals to fit 0.546" instead of 0.600" guides.
• Revised oil pan and valve covers with baffles

1984

• New camshaft design with 0.030" larger base circle diameter
• 0.015" shorter push rods and 0.015" shorter lifters to accommodate base circle (8.703" vs. 8.718")
• Oil groove added to the block behind cam bearing #1 and oil groove removed from cam shaft from the cam shaft

1985

• Oil pan went 20 bolts from 14 bolts
• New block, front cover and oil pan
• Torque-to-yield non reusable head bolts

1986

• Deck height reduced by 0.035" to accommodate 0.058" thick composition head gaskets
• Torque-to-yield reusable head bolts
• Water drain plugs added to block on both sides between freeze plugs
• 3.8 liter transverse FWD introduced
• VIN B with flat lifters
• VIN 3 with roller lifters
• New heads/valve train with pedestal style rockers
• Gerotor oil pump
• Needle bearing camshaft thrust bearing (P/N 25532588) *which works great with the turbo 3.8s!
• 3/8" dipstick hole with O-ring seal on tube

1987

• 3.8 liter transverse FWD changes
• Mid-year change to 0.057" longer push rods (7.966") to reduce
• cold start noise
• New timing chain cover and oil pump pressure regulator
• 7/16" dipstick tube with O-ring seal

1988

• 3800 transverse mounted FWD
• New on-center block design with balance shaft for improved primary balance
• Steel camshaft with improved precision tolerances
• Crankshaft balanced with 50% on bob weights
• Lighter Slipper skirt pistons with thinner rings for reduced mass

1989

• 3.8 liter RWD resurrected for special Turbo Trans Am 20th Anniversary edition
• 3300 (3.3 Liter) version introduced

1990

• EV-6 VIN L with one piece rear seal introduced in the FWD Regal
• Tuned Intake

1991

• 3300 version upgraded to one piece rear seal (blocks 25534816, 24502090, 24500498, and crank 25534817)
• All 3800s have one piece rear seal

1992

• 3300 version heads upgraded to same as 3800 but they have one less bolt hole on intake side

Application	Year	Block	Head	Crank
3.8L RWD	1977	1254083	1237722	1257125
.	.	1255862	.	.
.	.	1232438	.	.
3.8L RWD	1978	1261438	1257661	1260877
.	.	1261787	1257051	2551229
.	.	25505554	.	.
Turbo RWD	.	1261438	1257661	Rolled Fillets
3.8L RWD	1979	1261787	1262098	25500229
.	.	25505554	25504443	.
Turbo RWD	.	1261787	25504443	.
.	.	25505554	25504443	Rolled Fillets
3.8L RWD	1980-81	25506818	25505900	See 1978
	.	.	25506293	.
Turbo Monte/Regal	.	25506818	25505900	See 1978
	.	.	25506293	.
Turbo Riviera	.	25506818	25505900	See 1978
	.	25506485	25506293	.
3.8L RWD	1982	25506818	25510191	See 1978
.	.	.	25514290	.
Turbo Regal	.	25506818	25510191	See 1978
.	.	.	25514290	.
Turbo Riviera	.	25506481	25510191	See 1978
.	.	25524289	.	.
3.8L RWD	1983	25524289	25518445	See 1978
Turbo Regal	.	25524289	25518445	See 1978
Turbo Riviera	.	25524289	25518445	See 1978
3.8L RWD	1984	25524290	25518445	See 1978
.	.	25528601	.	.
.	.	25520040	.	.
Turbo Regal	.	25520040	25518445	See 1978
.	.	25518603	.	.
Turbo Riviera	.	25520040	25518445	See 1978
.	.	25520042	.	.
.	.	25528603	.	.
3.8L RWD	1985	25524140	25518445	See 1978
.	.	25520329	.	.
Turbo Regal	.	25520329	25518445	See 1978
Turbo Riviera	.	25520231	25518445	See 1978
FWD (Flat lifters)	.	25520043	25518445	25514267
3.8L RWD	1986	25526109	25518445	See 1978
Turbo Regal	.	25526109	25518445	See 1978
FWD Flat Lifters	.	25526110	25524248	25514267
FWD Roller Lifters	.	25526111	25524248	25514267
3.8L RWD	1987	25526109	25518445	See 1978
Turbo Regal	.	25526109	25518445	See 1978
FWD Roller Lifters	.	25526110	25524248	25514267
.	.	25526111	25529889	25527515
FWD Roller Lifters	1988	25528801	25527515	25514267
FWD 3800 Roller	.	25532617	25529723	25530502
.	.	.	25522646	.
3800 FWD Roller	1989	25528801	25527515	25514267
Turbo Trans Am	.	25526109	25536702	25511229
3800 FWD Roller	1990	25531617	25534250	25530502
.	.	.	25532646	.
3800 EV6	.	25532674	25534250	25534737

Contributed by:
Ken Mosher
kenmosher@home.com
 

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