Here's a selection of his blog post all of which you can find HERE
'“Cumulative Fatigue Failure for Dummies”
I broke a crankshaft while racing my 100S and that experience always haunted me because original 100S engine blocks are extremely rare and I knew that I had been very lucky not to have destroyed mine with that “blow up”.
Over the years I had encountered many cases of 100 crankshaft failures and it was the fear of another in the “S” that caused me to study the issue. The conclusions arrived at and described below prompted me to build a very special competition engine for the car which you can read about here.
WHY DO AUSTIN HEALEY 100 CRANKSHAFTS BREAK?
The Austin Healey 100 engine was actually developed from a 1929 Chevrolet design and several aspects of the design contribute to the crankshaft failure problem, these include:
- The engine size which at 2660 c.c., is around the upper limit of what is optimal in an automotive 4 cylinder unit.
- The relatively spindly forged steel crankshaft which has no “pin overlap” and is only supported in 3 main bearings
- The extremely big and heavy flywheel necessitated by the engine design.
To understand why these 3 aspects of the design are major issues it is first important to understand some less than common engineering terms and concepts.
CRANKSHAFT ROTATIONAL SPEED OSCILLATION.... FOLLOW THE LINK TO READ MORE.
We think that an engine should be tested on a dyno machine with the AH 6 cylinder damper on it. If such a test shows that vibration in the engine is eliminated from 0-3000 RPM then the 6 cylinder damper is working.
At HDR we are working on developing rubber repairs for all these flat dinner plate style dampers.
Starting with Jaguar and Wolseley models.
