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+--- Thread: Broken Mag Engine (/showthread.php?tid=4231)
RE: Broken Mag Engine - Charles P - 22-04-2020
(22-04-2020, 07:27 PM)Andy Cawley Wrote: Nick, I’m inclined to agree. Cranks usually break at the rear. I need to think positive and imagine that I have a pristine crankshaft??.
I've had the gears break at the front of a mag engine.
What usually happens is that the centre of the cam gear breaks. When that gear broke up it jammed the crank gear and that split into three parts. I don't think that this mode of failiure breaks cranks, which, as you say, usually break at the rear
c
RE: Broken Mag Engine - Andy Cawley - 22-04-2020
Chas, if that's the case, why no damage to the timing case?
RE: Broken Mag Engine - Charles P - 23-04-2020
(22-04-2020, 11:26 PM)Andy Cawley Wrote: Chas, if that's the case, why no damage to the timing case?
Once the crank gear spilt the whole timing gear train stopped revolving - and therefore nothing gets flung around by the forces of momentum or via the drivetrain as with a crank or rod breakage
c
RE: Broken Mag Engine - Terrytuned - 23-04-2020
This is what can happen if the crank breaks at the rear.
Terry.
RE: Broken Mag Engine - Charles P - 23-04-2020
(23-04-2020, 09:41 AM)Terrytuned Wrote: This is what can happen if the crank breaks at the rear.
Terry.
Gosh
On the bright side, the steel front bearing flange looks OK.......
RE: Broken Mag Engine - Andy Cawley - 24-04-2020
Wow!!!! That is most impressive, how many revs was it doing at the moment of failure??
RE: Broken Mag Engine - AustinWood - 24-04-2020
My Nippy engine broke like that when doing 30mph in top gear on a light throttle opening. Broke almost everything apart form the block, Head & flywheel. Including bending the camshaft.
RE: Broken Mag Engine - Zetomagneto - 24-04-2020
Hope it wasn't a proper Nippy engine
RE: Broken Mag Engine - Tony Griffiths - 24-04-2020
Bad luck with so much damage. I've only had one broken crank - driving out of the Thruxton circuit gates. Apart from the crank, nothing else was touched. Still, the tow back up the M1 at 70 m.p.h. was entertaining...
RE: Broken Mag Engine - Dave Wortley - 24-04-2020
I took my badly damaged crankcase to our local scrap dealer. It looked ok until you noticed that it was minus nearly all the front bearing housing. The dealer was impressed with the casting and now has it on his filing cabinet in his office.
The damage was caused by crank rear web fracture, as we came off the M1 after doing the Coast to Coast.