A TR4a owning friend of mine told me today how his crankshaft snapped
whilst doing a steady 80 mph on his way to Coventry. This is around
3,500 rpm on a TR4a. It broke between the flywheel and the back rod.
I'm told racing TR's have a low redline of around 5,500 rpm.
Is there a cure for this or is it a design feature ?? I suggested
nitriding the crank and having it the short motor balanced as
individual parts and then as a whole from fan to clutch. Are TR lumps
prone to this problem and is it an oil feed problem or are the cranks
weak ?
Any suggestions ??
My crank (ford OHV) is tuftrided and balanced and the engine red-lines
at 7,800. I use Cosworth bolts and special Vanderwell bearings, a Kent
OP5 oil pump, Valvoline 20-50 racing oil, extra sump baffling and the
oil is changed every 3,000 miles so I hope to avoid this kind of failure!
The flywheel is lightened also.
John Upham, (Chemical Physics Ph.D)
University of Sussex, Brighton, UK.
Email: kapn1%cluster.susx.ac.uk@uk.ac (BITnet)
kapn1@uk.ac.susx.cluster (Janet)
johnu%syma.susx.ac.uk@uk.ac (BITnet)
johnu@uk.ac.susx.syma (Janet)
Tel: +44 273 680500 (eve)
Tel: +44 273 678332 (day)
Fax: +44 273 671966
"I've counted them all out and I've counted them all back"
Murray Walker (?) commentating on the restart at F1 WC, Spa, 1990
|