Quarter Midget Engine Key ( Keystock )

The engine key is the small piece of steel that keeps your engine gear hub from spinning free on the crankshaft. It costs two dollars and it stops your night before it starts when it shears or walks out of the keyway. Most teams keep a handful in the toolbox for exactly that reason.

This is 3/16" keystock from Ultimate QM, cut to length for quarter midget engine use. Plain steel, square stock, standard fit for the keyway on common quarter midget powerplants.

When to replace it

Pull the key and look at it any time you have the engine hub off. If the edges are rounded, twisted, or peened over, it is done. A rounded key lets the component shift under load, which chews up the keyway in the crankshaft itself. That repair is not two dollars.

Also worth swapping after any hard hit or a jammed chain even if it looks fine. Steel that has taken a shock load is not the steel you want holding all of your forward drive.

Tips from the pit

Set the key in the crank keyway first, then slide the component over it. Do not tap the component down onto a key that is sitting proud, since that is how keys get bent before they ever see a lap. Check that the key sits flush and does not rock in the slot. If it does, the keyway is worn and needs a look.

Buy a few. They are small, they disappear on a trailer floor, and you will need one on a Saturday morning when nothing is open.

Details

• Part number: qm622
• Brand: Ultimate QM
• Type: Hardware
  
• In stock and ready to ship