Ellis wrote:Engine internals...and other weaknesses...
As everyone knows they are prone to breaking crankshafts. Lots of theories exist as to what to do and not to do
and while you may think you are doing the right things they will break whenever they feel like it.
At the 2009 Baskerville Historics Holden Reunion meeting just to prove that nothing changes after 40-45 years of racing
out of around 20 Humpies ....2 blew headgaskets, 1 broke gearbox, 2 broke cranks and 1 rolled.....
Mine didnt fail then...it waited another 15 months till this year and my crank went at Baskerville. Its not too bad , it
lasted 4 1/2 years.
About all that is done to the standard crank is balancing, better rod bolts and main bolts are used along with main bearing cap strengtheners on centre mains. Billet steel cranks are now available but are around $4k so not cheap and not too many are in use.
Lightenned flywheels and larger harmonic balancers are used along with enlarged and baffled sumps. The heads are ported and planed and larger valves are fitted along with tubular pushrods and with a bore out to 3 3/16" most use hi top pistons but some still run flatop.
Camshaft grinds are free and most use a well known Cam grinder in Melbourne...Clives Cams...no substitute for 45 years or so experience. Aluminium or steel timing geras replace the old original fibre versions.
The gearbox remains standard or maybe fit an EH cluster and a few circlips get silver soldered. The ratios in the gearbox are free and some run close ratio boxes which shifts low up and moves 2nd closer to top. A higher ratio diff is usually then required for some circuits.
Differential ratios are free but the original housing must be retained. For Nb regs drum brakes must remain but finned drums are permitted. Wheels for Nb must remain at 15" but are allowed to be 6" in width. The original old hubs were prone to cracking so later model 13" hubs are permitted with adaptors to take them back to suit 15" stud pattern. LSD or lockers are permitted. Not many of the cars running comply to these Nb specs so are logbooked as Targa class and run disc brakes and 13" wheels so are not permitted in Nb. Quite a few run later red motors and 4 speed boxes but the few purists retain Nb specs which almost mirror the old Appendix J rules from 1960.
So you see nothing has changed since the heady days of the 60's... except for one really important improvement...Tyres.
A one piece crank replaces the 2 piece from a few weeks ago....
