Why the Buick 225 Dauntless V6 Flywheel Is So Heavy

[Moses Ludel]

I follow the Goodson Tool videos, and this #Short caught my attention.  When the Buick 225 was a Kaiser/Jeep CJ and Jeepster mainstay, the flywheel played a large role in keeping the engine running as smoothly as the odd-fire design would allow.  (The 90-degree odd-fire engine was notoriously "rough as a cob" as one Jeep® engineer noted in the day.) 

In the #Short below, a 225 Dauntless flywheel gets resurfaced at a quality automotive machine shop.  The size/mass of this iron flywheel is exceptionally heavy, especially for a smaller displacement engine like the Buick 225 V6.

So why is the flywheel this heavy?  Buick and Jeep did everything possible to smooth out the odd firing pulses of this engine, and the mass of the flywheel helped.  It also helped keep the engine from stalling in off-pavement rock crawling at low engine speeds.  These engines had much more torque than the F-head four cylinder engine, but Jeep® hedged its bets with a heavy iron flywheel.

In the eighties and nineties, I built two magazine/book project Toyota FJ40 Land Cruisers, each with a stroker 383 Chevrolet V8 engine.  In both cases, I used the 168-tooth GM "truck" flywheel rather than a smaller mass 153-tooth passenger car type.  My motive was to mimic the Dauntless V6. 

One of these 4x4s went on the Rubicon Trail in the late eighties.  The engine had a mild CompCams 252 grind torque cam and a Quadrajet 4-barrel carburetor jetted for sea level.  At 8,000 feet elevation, the 383 would not stall while inching along at a crawl pace on the rocks.  I could apply the brakes with the clutch engaged in low range, first gear and bring the engine's speed down to 400 rpm without bucking, stalling or stumbling.  That's the value of a heavy mass flywheel for off-road rock crawling: