Metallurgical Testing & Consulting Engineers

Silverdale. NSW. 2752. Australia

(Near Warragamba Dam -Covering Sydney Metro)

Phone: (02) 4774 1017

Mobile (Stephen Hooker): 0419 498 115

 

INFO SHEET - CRACK TESTING

Metallurgical Testing and Consulting Engineers provide a non-destructive testing and advisory service to the high performance motor-racing industry. We also provide an in-house parts improvement capability including aerospace quality shot peening and cryogenic treatment. Our prompt and professional service ensures that our Customers can operate their business operations at a high level of confidence and reliability.

WHAT SHOULD I HAVE TESTED?

The question is trying to determine which parts are critical, and how often they should be inspected. There are life-and-death items on every car such as axles, hubs, spindles, hub carriers and steering arms that could cause a serious accident. Other high stressed parts in the engine, transmission and driveline could cost a lost race and some expensive internal damage. The cost of inspection is insignificant compared to normal teardown time and the potential loss from failure.

Typically the top race teams check: hubs and hub carriers, rack and pinion, drive shafts, universal joints/yokes, transmission input and output shafts, differential ring and pinion units, intermediate gears, engine valves, con-rods, pistons, piston pins and crankshafts.

It is advisable to crack test gears at least once per season, however they should be inspected after any shunts or accidents. Input and output shafts take a lot of abuse and should be crack tested every 1000 km. Examine the axle shafts for twisting at the ends of the splines every race.

Cast wheels and wheel centres are popular, and in many cases have been in service for a long time. At least once a year the tires should be dismounted, the wheels thoroughly cleaned, and given a good visual inspection. If they pass a quick visual inspection for damage, have them bead-blasted and crack tested. Advanced eddy current crack testing techniques utilised by MT&C Engineers also allow inspection of the wheel, without resorting to removal of the paint. Localised deformations of the rim are often repairable, but brittle cast materials do not like being bent back.

Contact Stephen Hooker on 0419 498 115 for your crack testing requirements today. We can also pick-up and deliver in Western Sydney.

IT'S BEEN TESTED, WHAT DO I DO NOW?

If the part comes back as cracked find out if the tester has any ideas on whether the part is serviceable. The part may require minimal reworking to salvage the damage. It is possible that highly stressed parts will be recommended for replacement . . . do not put the part on the shelf, or flog it off . . . experience has shown that these parts always come back to haunt you!

HINT: If the part has to be repainted after the inspection, use a thin layer of brittle paint. If the part is overloaded, the paint will crack before the part, giving you a chance to find a stronger replacement. This is highly recommended for cast wheels, and cast wheel centres.

Fatigue failures are easily recognised, and usually start from a focal point on the surface. These focal points are stress raisers such as fillets, holes, keyways, seams, laps, tool marks, scratches or structure variations. When fatigue failures are encountered, these stress raisers should be eliminated where possible.

Previously peened parts that exhibit damage that has been dressed back (eg. conrods dressed after a lifter failure) can be shot peened to restore their original fatigue resistance.

Also, if the failure is a common occurrence find out if their are any processes that may extend the life of the part. Processes offered by MT&C Engineers such as dressing, cryo treatment and shot peening can be used in many cases to extend the life cycle of critically loaded components.

AUTOMOTIVE TESTING & SERVICES | CONTACT US | CRACK TESTING | CRYOGENICS | DRAG BIKE | FAILURE STATISTICS | LINKS | METALLURGICAL SERVICES | MISC SERVICES | PEEN REPORT | PROJECTS | SIDECAR RACING | JEDI RACING | SHOT PEENING

Just for further information, here are some statistics on a sample of parts we have tested. The failure rate indicates the percentage of parts tested that revealed a crack.

COMPONENT

FAILURE RATE, %

COMPONENT

FAILURE RATE, %

BRAKE DISC

67

MARINE PROPELLER

50

CONROD

15

MARINE PROPELLER SHAFT

25

CRANKSHAFT

25

MARINE RUDDER

50

CYLINDER HEAD

40

PINION GEAR

10

DIFFERENTIAL SET

29

PISTON

35

ENGINE CRANKCASE

25

REAR AXLE

21

FASTENER - BOLT

12

ROLLER ROCKER

9

FASTENER - NUT

13

STAINLESS / Ti VALVE

36

FLYWHEEL

17

STEERING ARM

33

FRONT AXLE STUB

37

STEERING BALL ROD END

35

FRONT HUB

21

SUSPENSION ECCENTRIC

17

GEARBOX SHAFT

13

WHEEL CARRIER

13

KING PIN

22

WHEEL CASTING

24

This page last updated: 03/02/17