Velvet Drive

[DOGGYDOO]

I Am Assembling A Formula 23'3 With An Inboard Setup Utilizing An Olds 455 Mated To A Velvet Drive 72c 1to1 And I Have A New Damper Plate. Do I Need A Flywheel Or Flexplate For The Application And Can Someone Explain The Difference? I Have Several Flexplates But Would Need To Acquire A Flywheel But I Noticed Most Jetboats Use The Flexplate. Thanks Dave

[stonebreaker]

In automotive applications, flexplates are used with automatic transmissions and flywheels are used with manual transmissions. Does your transmission have a torque converter? If so, it probably uses a flexplate.

[Corpus Skipper]

My Crusaders with 72Cs have flywheels. I think the flexplate would move the damper too close to the engine, not engaging the tranny input shaft splines enough. Is your starter a top mount? (mounted to bell housing up high and facing aft) If so, you also need to make sure your ring gear is on the aft face of the flywheel.

[DOGGYDOO]

I Understand Your Point About The Spacing Differences Between A Flexplate And Flywheel. I Am Going To Use A Stand Mount Starter On My 4555 Which Means It Will Be Bolted To The Block In The Standard Automotive Location. My Main Concern Was If The Flywheel Was Used Instead Of Flexplate Because Of Inertial Differences With The Borg Warner Versus A Jet Drive Pump. I Do Know From The Engine That I Removed That It Had A Flywheel. Also Wondering If There Are Any Performance Differences Between The Two. I Do Have Spacing Shims That Could Be Installed With The Flexplate To Align The Shaft Spacing Properly. Thanks Dave

[Jango]

Velvet Drive Trans. are intended to be used with a standard shift type flywheel. I asked this same question and was reminded that the lighter flex plate will have far less inertia enabling rapid RPM change(over reving). The flex plate should work, but you run the resk of blowing your engine if the prop becomes air born.