Consider the Buick V6, it is short, plentiful, and powerful. What more
can you ask for in your short Jeep. The Buick is well suited for a
swap into any short CJ-5, CJ-3B, CJ-3A, CJ-2A, or their military
brethren. It isn't so powerful you'll rip your frame apart and break
your axles and it is spunkier than the F-Head and L-Head engines. It
is also easy to buy and buy parts for.
From 1966 until 1971 Jeep used the Buick 225 V6 as the optional engine
in CJs. Kaiser purchased the tooling to build the engine from Buick in
1967 and began production of the engine. The "Dauntless" 225 is an
"odd fire" engine meaning the cylinders fire odd order. The odd-fire
design cause a the engine to idle a bit rough. This version of the
engine and parts from these Jeeps can be used to swap a Buick V6 into
One big advantage of the Dauntless 225 V6 is the heavy flywheels
used on these engines. The flywheels come in 75lbs and 100lbs versions
to create low end torque. The normal car flywheels are closer to
The bid disadvantage of the 225 is it is more difficult to fuel
inject because of the odd fire ignition. The tachometer signal will
confuse the computer of regular TBI fuel injection.
When AMC purchased Jeep, they started putting AMC engines in Jeeps.
The Buick V6 was not used after 1971 and with the gas crisis, Buick
became interested in the V6 engine again. They purchased the tooling
back from Jeep in 1974 and reworked the engine so it use components
from the Buick 350 engine. The larger bore increased the displacement
to 231 cubic inches.
In mid 1977, Buick introduced the first "even fire" version of the
Buick V6. This engine has a smoother idle, but more vibration than the
older engine. The odd fire engine uses a distributor cap with equal
spaces between the plugs on the distributor cap and the even fire
engine has unequal spaces between the plugs on the distributor cap. It
is not very intuitive, but that's the way it is.
The 231s are internally balanced and the 225s are externally
balanced. Technically, you need to rebalance a 231 if you replace the
flywheel or install a flywheel in place of a flex plate. Some people
report that they have had no problem swapping different flywheels on
these later engines with out rebalancing.
Later Buick 231s use multiport fuel injection. The Buick V6s never
used TBI fuel injection from the factory.
During the early 80s some large rear wheel drive cars used a version
of the 231 with a bigger bore. The displacement of the 231 was pushed
up from 3.8L to 4.1L or 252 cubic inches. This engine has the same
external dimensions as the 231 and can be told from the 231 by the
4.1L cast in the drivers side rear instead of 3.8L. Keeping these
engines cool is a bit more challenging than the 3.8L, but it is nice
to have the extra displacement.
Project Pieces & Parts Engine Installation
: Project Pieces & Parts
finally gets the fired up with a Buick 231 V6 sitting on engine mounts
from Advanced Adapters
Corvette Starters: The Corvette used a nice Denso high torque and
light weight starter. This is a great and relatively cheap way to
upgrade the starter in your Jeep with Chevy or Buick engine.
Buick 225 V6
The "Dauntless" 225 V6 engine was used in CJ-5s,
CJ-6s, and Jeepster/Commandos.