Spanners had to get the spanners out again. Local racing has been cancelled again because of the 'you know what virus' so I thought I'd do some driveway testing. A couple of spirited runs to check out the new mesh screens I made for the carby intakes. Wasn't happy with them so I deleted them and it made a huge difference. Put the racecar back into the trailer and had arranged to get the certification done in a couple of weeks. When I spoke to the certifier he told me to make sure the kill switch actually killed the engine. Back out to the trailer, fired the car up and found it didn't kill the engine. No excessive revs were used in the testing. Changed the alternator wire and hit the starter. Horrible internal clunk. Changed the starter, wouldn't turn the engine. Rolled the car out of the trailer and into the shed. Pulled the plugs and engine wound over. Plugs back in, hit the starter, it fired and locked. Pulled the sump and everything looked good until I rotated the flywheel by hand. Matching bookends! Good thing it didn't happen at full song. No debris in the sump but due to state wide lock down I can't get another crank ground so I changed out the dead engine and put the spare in. Shit happens.
Yes, it's the Archilles Heel of the Holden Grey. They never did like being over revved. The speedway blokes used to break heaps of them but mostly due to the constant on-off the throttle. I'm starting to wonder if my problem is the very light flywheel I'm running. Mind you, this engine has done over 120 passes since the last broken crank, doing something it wasn't designed for so I can't complain. Yes, they are a cast crank. There was a place over here that would build billet cranks for these old engines but the price tag was around the $2,000 mark, way too much for my retired pockets.
Was the cast crank turned down? Cast cranks don't much like having the surface removed, sometimes gives'em improved fracture starting areas.
Do you have a vibration damper on the snout? If not that will help, even if you have to adapt one from a similar engine.
Yes, there's a Ross Racing harmonic balancer on the snout. These engines only have 4 mains so they were never designed for this sort of punishment. They usually break through the oil gallery. In an ideal world I'd love to have the money to have a forged crank made but I'd have to sell both testicles plus an arm and a leg to do it.
I like your thinking but with only one leg I'll go around in even more circles than I do now. As for the testicles, what to scratch when pondering?
The Jalopy Journal
