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The "Dauntless" 225 V6 engine was introduced in 1966 in the CJ and C101 models. The V6 configuration of the engine makes it very compact which is a big plus in tight Jeep engine compartments. Kaiser purchased the tooling to build the 225 from Buick and later, AMC sold the tooling back to Buick.
A descendent of this engine, the 231 (3.8L) V6, is used in GM cars to this day. The modernized and common 231 is a good candidate for replacing a blown 225. There are differences in the balancing of the engine though, so it can be tricky. The 225 is externally balanced and the 231 is internally balanced. This means you cannot just throw your 225 fly wheel on a 231, the 231 must be balanced.
The flywheel itself used with the 225 is not typical. The flywheels used in the Jeep vehicles are very thick and heavy to help prevent stalling at low speeds. The flywheels used in Buick cars are much lighter.
Since the 225 is a Buick engine, it uses the standard Buick bell housing. The standard Buick bell housing will bolt to a SM420, so this is probably the best transmission swap option for Jeeps equipped with this engine. The T-14 and T-86 3 speed transmissions used behind this engine are not known for their strength.
The Buick 225 uses a cast iron block and cylinder heads with mechanical lifters and 3 main bearings.
| Dauntless Buick 225 V6 | |
|---|---|
| Bore x Stroke | 3.75" x 3.40" |
| Displacement | 225 (3.68L) |
| Compression Ratio | 9.0:1 |
| Horsepower (net) | 160@4200 |
| Torque (net) | 235@2400 |
| Main Bearings | 3 |
| Valve Configuration | OHV |
| Fuel | 2bbl |