What does a flex plate do?

The flex plate bolts to the engine crank shaft and to the torque converter of your automatic transmission. When the engine starts and is running the flex plate turns, which turns the torque converter and powers your hydraulic pump in your transmission. They sometimes will crack from just metal fatigue and vibration.

How do I know what flexplate I need?

The key to choosing the correct bolt pattern and tooth count is measuring the torque converter you are using. A 153 tooth flexplate will be paired with a torque converter that has a 10 3/4-inch bolt circle. A 168 tooth flexplate uses a 11 1/2-inch bolt circle.

What is an SFI flexplate?

2.0 DEFINITIONS. 2.1 Automatic Transmission Flexplates are circular plates that mount between the engine crankshaft and the automatic transmission converter. They replace stock units and are used in racing applications. 2.2 Flexplates are also called flywheels in some configurations.

What causes flex plate failure?

Aside from a manufacturing defect, the only things that will cause a cracked flex plate are improper torque on the plate bolts at the crank and torque converter and the most common cause of transmission to engine misalignment; sometimes caused by missing alignment dowel pins that mate the transmission to the engine.

What happens when a flex plate breaks?

When a flexplate cracks, it often produces a loud knocking noise as it rotates. The sound is very similar to a bad engine rod and is often misdiagnosed. Removing the bolts to the torque converter and sliding it back into the transmission will often reveal the real problem.

How do you know if your teeth are flexplate?

With the engine idling, use a shop light to illuminate the flexplate and watch the rotation of the teeth end of the plate. A good flexplate does not wobble. A warped flexplate wobbles around the outside ring teeth, even if the warp is slight.

What does SFI rating mean?

Parts that carry an SFI approval are certified to be safe for racing. This means they are designed and tested to meet certain safety requirements. The requirements are established by The SFI Foundation, Inc.

Who makes SFI Flexplate?

ATI SFI Flexplates for Racing Automatic Transmissions. Manufactured in the USA on state-of-the-art CNC equipment, ATI’s Flexplates are created from SFI-spec steel and are SFI 29.1 Certified and are double MIG/TIG welded for additional strength and lasting precision pass after pass.

Why is it called a flex plate?

The name refers to the ability of the disk to flex across its main axis – bending side to side – to take up motion in the torque converter as rotational speeds change.

How much does it cost to fix a flex plate?

How much is a replacement flex plate? The flex plate or flywheel plate should cost somewhere in the region of $50-160, on average.