Comet Torque Converter Belt Troubleshooting Guide

A worn or damaged torque converter belt can be a sign of a problem somewhere in the drive system. Simply replacing the belt may not solve the issue if the underlying cause is excessive slipping, pulley misalignment, incorrect belt installation, excessive RPM, or a problem with the clutch or pulley system.

This guide covers some of the most common Comet torque converter belt problems, what can cause them, and what to check before installing another belt.

Quick Comet Belt Troubleshooting Chart

1. Belt Is Worn Thin in One Portion

If only one portion of the belt is noticeably worn thin, the primary cause identified in the troubleshooting guide is excessive clutch slipping.

Possible contributors include:

• A locked track or axle
• Engine idle speed set too high

What to Check

Rotate the track or axle by hand to make sure it is free. If the clutch has been damaged by excessive slipping, it may need to be repaired or replaced.

Also check the engine idle speed and reduce the engine RPM if necessary.

2. Driver Clutch Turns While the Engine Is Idling

If the driver clutch is turning while the engine is idling, two possible causes identified in the troubleshooting guide are:

• Idle speed is set too high
• The belt is too short

What to Check

Try reducing the engine RPM and verify the belt length against the application specifications before replacing the belt.

3. Belt Is Cup-Shaped or Concave on the Sides

If the sides of the belt have developed a cup-shaped or concave wear pattern, the troubleshooting guide points to excessive runout on the clutch.

What to Check

• Inspect the clutch for excessive runout.
• Repair or replace the clutch if necessary.
• Check the center distance between the drive and driven components.

4. Belt Is Disintegrating

A belt that is coming apart or disintegrating can be the result of excessive belt speed.

What to Check

Check engine RPM, particularly at high speed. If excessive belt speed is causing the belt to disintegrate, reduce RPM at high speed.

5. Belt Rolls Over at High Speed

A torque converter belt that rolls over at high speed can indicate a problem with the pulley system or belt speed.

Possible causes include:

• Pulley system is out of line
• Drive belt speed is too high
• Excessive runout on the clutch

What to Check

Start by checking pulley alignment. If the system is properly aligned, check engine RPM and inspect the clutch for excessive runout.

Corrective actions include aligning the system, reducing RPM, and repairing or replacing the clutch when necessary.

6. Cord Breakage Along the Belt Edge

If the cords along the edge of the belt are breaking, possible causes include:

• Misalignment of the system
• Belt not properly installed

What to Check

Inspect the alignment of the drive system and verify that the belt has been installed correctly.

7. Cracking Between the Belt Cogs

Cracks developing between the cogs are identified as a sign that the belt is wearing out.

What to Do

Replace the belt and inspect the drive system for other signs of belt-related problems.

8. Broken or Torn Belt Cogs

Broken or torn cogs can occur when:

• The belt is not installed correctly
• The belt is rubbing against another component

What to Check

Verify that the belt is installed correctly and inspect the drive system for anything that could be contacting the belt.

Look for signs of interference around the belt and pulley system before installing a replacement belt.

9. Belt Is Worn Unevenly on One Side

Uneven wear on one side of the belt can indicate that the drive system is out of alignment. A loose engine mount is another possible cause.

What to Check

• Check alignment between the drive components.
• Inspect the engine mount.
• Tighten the engine mount if it is loose.

10. Belt Has a Glazed or Baked Appearance

A belt that looks glazed or baked can indicate excessive slipping.

The possible causes listed in the troubleshooting guide include:

• Not enough pressure on the belt
• Horsepower too high
• Oil on the pulleys

What to Check

Inspect the driver clutch springs and weights. Also clean the belt and pulley faces and make sure they are dry.

If oil or other contamination is present on the pulley faces, address the source before putting the system back into service.

11. Belt Top Width Is Wearing Excessively

Excessive wear across the top width of the belt can be caused by:

• Excessive slipping
• Scratched or rough pulleys
• Incorrect belt angle for the pulley faces

What to Check

Check the drive clutch for proper engagement and inspect the pulley faces for damage or rough surfaces. A damaged pulley may need to be repaired or replaced.

Also verify that the belt and pulley configuration is appropriate for the application.

Don't Just Replace the Belt

One of the most important things to remember when troubleshooting a torque converter belt is that belt damage can be a symptom rather than the actual problem.

If a replacement belt quickly develops the same type of wear, inspect the rest of the drive system before installing another belt.

Pay particular attention to:

• Belt length and application
• Belt installation
• Pulley alignment
• Engine RPM
• Clutch condition
• Clutch runout
• Engine mount condition
• Pulley condition
• Possible belt interference
• Oil or contamination on pulley faces

How to Diagnose Your Belt Problem

A good place to start troubleshooting is by looking closely at the belt itself. The wear pattern can provide a useful clue about where to look next.

Before Ordering a Replacement Comet Belt

Before ordering a replacement belt, verify the application and belt specifications. Using the correct belt for the torque converter system is an important part of troubleshooting belt problems.

If you're unsure which Comet torque converter system you have, identify the series before selecting a replacement belt. BMI Karts provides additional information covering Comet torque converter series and belt applications.

Final Troubleshooting Checklist

Finding the cause of the belt failure before installing a replacement can help prevent the same problem from happening again.