its been a long time coming

ian.stewart · Post by **ian.stewart** » Sat Feb 02, 2008 1:55 pm

At last I have managed to move some pics from an obscure secure file my son had placed them, for those of you who remember, I cattled my engine last year, and heres the reason why----

broke these as well,

Nobody I have spoken to including a couple of Pro engine builders have ever seen one break.

badger · Post by **badger** » Sat Feb 02, 2008 5:01 pm

I've seen one go but it was a long time ago. Caused by force-fitting over corrosion on the crank nose!

ChrisJC · Post by **ChrisJC** » Sun Feb 03, 2008 9:39 pm

Any idea why?

Chris.

ian.stewart · Post by **ian.stewart** » Sun Feb 03, 2008 9:53 pm

I have a fair idea/guess as to what happened,
Drag raging, doing a burnout @7k, lifted off, and it went Pop, looking at the wear on the gears, especially the cam gear, I would guess, when you lift off and the engine in slowing down the chain goes slack on the front side, which allowed the chain to climb the sprocket and take off a tooth, unfortunatly, the tooth right beside the keyway, which went under the chain and cleved its way thru the weakest spot, and the rest is history, bent crank, tipped valves etc, surprisingly, the crank journals are spotless and so are the bearings apart from the thrust faces, I was wondering if that could have been a contributary to the failure with the crank walking fore and aft, unfortunatly, the crank is bent 0.004 on the nose due to the breakage, so its scrap.