basics, flexplate vs flywheel

[grumpyvette]

I forget some of the new guys don,t know the basics, I got asked whats the differance between a flexplate or a flywheel.

 

 

flywheels are used to mount clutches on manual trans cars

flexplates are used to mount torque converters on auto trans cars

 

 

the differance between the 153 and 168 tooth size in a flexplate or flywheel is the diameter , small VS large both a flexplate and a flywheel have a ring gear to allow the starter to spin the engine over to start it

 

 

the 168 is generally prefered BUT be aware that there are a few rare applications where the 168 will cause clearance problems with the trans case or starter in some combos, it would be a good idea in many cases to stay with the size that came with the transmission and starter your using, also be aware that some aftermarket high torque starters have dual mounting holes to accept/(work with) either flexplate diam. and give max header clearance,( header heat and starters don,t play well together) but some starters will only work with a single diam.,since high torque starters can get expensive and header clearances can get tight thats something to think about

keep in mind the clearances your working with and that mini starters are comonly set up to work with either size, but some clutches and torque converters will only fit on the larger size and some bellhouseing will only fit the smaller size, ask questions, everything must match the application and clearances

the 168 tooth flexplate/flywheels are a larger dia. but MANY bellhousings will fit either one and headers are NORMALLY designed to clear either size, and yeah, you may need a high torque mini starter with over 10:1 cpr, and the mini-starters use a gear reduction to increase torque to the flexplate, usually between 3:1 and 4:1 that more than make up for the smaller motor size.and some headers do cause clearance problems with the stock starter.many starters work WITH EITHER SIZE FLEXPLATE/FLYWHEEL, many mini-starters also allow you to index or clock the starter for maximum header clearance. and add or remove them without removing the headers unlike the stock starters, so keep that in mind

 

keep in mind stock starters are HEAVY and you save weight, get additional; clearance and usually gain effective starter torque due to the mini-starters being geared to aid leverage

Id suggest getting a starter with the dual bolt pattern that fits both size flexplate/flywheels

 

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