Tech Tip: Troubleshooting Common Crank Grinding Problems – UnderhoodService

Tech Tip: Troubleshooting Common Crank Grinding Problems

Using an improper wheel is most likely to blame for metal particles lodging in abrasive grains or in wheel pores. Try using a wheel with a coarser grit or more open structure to provide chip clearance. Also try using more coolant. Faulty dressing could be another cause of wheel loading. Examine your diamond tool and replace it if it appears to be worn. A worn diamond will appear rounded.

PROBLEM: Wheel loading
Using an improper wheel is most likely to blame for metal particles lodging in abrasive grains or in wheel pores. Try using a wheel with a coarser grit or more open structure to provide chip clearance. Also try using more coolant. Faulty dressing could be another cause of wheel loading. Examine your diamond tool and replace it if it appears to be worn. A worn diamond will appear rounded. During the dressing process, a rounded diamond will roll some of the severed wheel back into its pores. This causes the wheel to become loaded, even before grinding. Also, check your coolant to make sure it’s not too concentrated. And, be sure to change dirty coolant.

PROBLEM: Wheel glazing
If your wheel looks shiny and feels slick, be sure that the wheel you are using is the right one for the application. You may need to choose a wheel with a coarser grit or softer grade. Or, you can try manipulating the wheel to get a softer grinding effect. Be sure to use a sharp diamond tool to dress the wheel. Turn the diamond 1/4 turn every fifth dressing. Use faster traverse and deeper penetration. The grinding operator should try using more in-feed, this should help deter wheel glazing.

PROBLEM: Fine spiral or thread on work
This is most likely caused by a faulty wheel dresser. Replace cracked diamond or reseat diamond. Try using a slower traverse speed. Rotate diamond every fifth dressing. Be sure that set screw on diamond is tight. Dress with less in-feed and do not allow the diamond to stop while in contact with the wheel. Make sure the you move the diamond evenly across the face of the wheel and re-radius the edges of the wheel.

PROBLEM: Tapered journal
Examine your grinding machine thoroughly. Correct worn ways and alignment of tail-stock and head-stock. Tighten their spindle bearings or replace worn out bearings. Re-level the machine. Check the dressing fixture for rigidity and examine the diamond itself. Try moving the point of the diamond closer to the fixture, but do not over-extend. Diamonds must be submerged in coolant continuously during dressing to maintain constant temperature. If the diamond’s shank is allowed to expand or contract with temperature change, taper will result.

PROBLEM: Chatter marks
Long, regular-spaced chatter marks that form a checkerboard pattern woould indicate that your wheel is out of balance. Re-balance the mounted wheel using th appropriate stand provided with the grinder. Remember to run the wheel without coolant to throw-off excess water to prevent water from settling at the lower edge of the wheel during storage. The wheel might also be out of round. To remedy this, true sides to face and rebalance. Regular-spaced chatter marks are usually caused by general vibration. Check for loose motor mounting bolts (head stock or wheel head) or a loose spindle pulley. Also check the balance of the motor. General chatter marks are typically due to faulty dressing. For best results, be sure to use a sharp diamond tool, rigidly held close to the wheel.

Tech Tip courtesy of Goodson Tools.

You May Also Like

Understanding Coolants

All-season coolant used inorganic acid technology and worked great for almost 30 years.

In the 1960s, coolant was changed twice a year. In the fall, antifreeze with ethylene glycol-based coolant was put into the engine to prevent the coolant from freezing and cracking the block when a cold front hit. Often, if the engine got hot, the antifreeze would boil off. In the spring, the engine would be drained and filled with water and maybe a small can of an anti-corrosion treatment.

Ignition System Do’s and Don’ts

Why do ignition systems give technicians problems when diagnosing ignition-related misfires? The answer is that some technicians use tests that might give inconclusive results or do damage to the coil or drivers inside a module.

Tools To Service Serpentine Belts

Servicing the serpentine belt on some vehicles is a tough task.

Battery Charging and Diagnostics

Here are six tips to use when diagnosing a vehicle with a dead battery. 

Why Do Timing Chains Stretch?

As the timing chain wears, it can change the timing of the camshaft and crankshaft.

Other Posts

Carbon Deposits and Direct Injection Engines

The primary cause of these problems is that fuel and added detergents are not hitting the back of the intake valves.

Acura Turbo Engine Service

It is important to check the operation of the solenoids that control vacuum to the actuators.

Subaru EJ25 Head Gasket Problems

Most of the EJ head gasket failures occur around the 100,000-mile mark and start as a slow oil or coolant leak.

New Oil Specifications

Many 0W16 oils have a new donut certification mark on the bottle called API SN-PLUS and SN-PLUS Resource Conserving.