steve200b Posted May 31, 2014 Share Posted May 31, 2014 Any ideas as to the reason for the nose to break of the crank? The motor was balanced etc. very lucky we found it before more damage was done Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/ Share on other sites More sharing options...
XKLABA Posted May 31, 2014 Share Posted May 31, 2014 Did it have an extended oil pump drive fitted ? Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299386 Share on other sites More sharing options...
steve200b Posted May 31, 2014 Author Share Posted May 31, 2014 Yep Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299388 Share on other sites More sharing options...
89CAL Posted May 31, 2014 Share Posted May 31, 2014 Perhaps it was fitted incorrectly. Too much heat in the crank or retaining bolts/screws not installed properly Just a random guess seen as it sounds like you had a crank collar installed and thats where it broke. Better photos of the fatigue point? Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299435 Share on other sites More sharing options...
turbo76lx Posted May 31, 2014 Share Posted May 31, 2014 What brand balancer, ATI, Ross? Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299450 Share on other sites More sharing options...
Adriano Posted May 31, 2014 Share Posted May 31, 2014 Factory balancer bolt and washer? Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299467 Share on other sites More sharing options...
steve200b Posted May 31, 2014 Author Share Posted May 31, 2014 Ross balancer and factory bolt with washer Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299481 Share on other sites More sharing options...
Ben C34 Posted June 1, 2014 Share Posted June 1, 2014 (edited) That sucks man. I assume it would have bent some valves. .. Could it have been something silly like the bolt bottomed out in the crank? Edited June 1, 2014 by Ben C34 Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299508 Share on other sites More sharing options...
steve200b Posted June 1, 2014 Author Share Posted June 1, 2014 Very lucky made 480kw with some wheel spin and then lost 100kw and then started looking for the issue and found that. No other damage done lucky. Motor out today for another crank and some rings etc then back on the road in a few weeks Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299535 Share on other sites More sharing options...
steve200b Posted June 1, 2014 Author Share Posted June 1, 2014 Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299545 Share on other sites More sharing options...
89CAL Posted June 1, 2014 Share Posted June 1, 2014 Ill look at my wear guide later if I think of it but looks like it has fractured over a longer period of time. How long was this crank in use in this form for? And what Is the previous history of this particular part of the crank? (Heating to remove gear, crank collars on off etc) Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299609 Share on other sites More sharing options...
steve200b Posted June 1, 2014 Author Share Posted June 1, 2014 Was in a low km one owner r31 before this build. It has had two years of abuse with no issues. Just thought it was a strange place to break Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299636 Share on other sites More sharing options...
SimonR32 Posted June 1, 2014 Share Posted June 1, 2014 Ross balancer and factory bolt with washer Funny that... Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299664 Share on other sites More sharing options...
steve200b Posted June 1, 2014 Author Share Posted June 1, 2014 Funny that...I assume you use something different? Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299782 Share on other sites More sharing options...
Badgaz Posted June 1, 2014 Share Posted June 1, 2014 that happened to one of the drift guys in NZ but it was the other end...his was because he had too much weight on the back of the crank triple or twin plate clutch i believe. Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7299865 Share on other sites More sharing options...
SimonR32 Posted June 1, 2014 Share Posted June 1, 2014 I assume you use something different? Yes I do after seeing so many issues directly related to Ross balancers. To give you an idea I know a crank that was pulled out that was bent in exactly the same spot with Ross balancer. 1 Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7300107 Share on other sites More sharing options...
R32 TT Posted June 1, 2014 Share Posted June 1, 2014 Yeah not a fan of them either... Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7300116 Share on other sites More sharing options...
GTRPSI Posted June 1, 2014 Share Posted June 1, 2014 Looks like the woodruff key is at a slight angle and has moved inwards causing extra stress on the cranks snout. Id say the balancer was moving on the crank and the vibration caused it to crack. Ive heard similar about Ross dampners, that why we went with a ATI one from the start. Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7300121 Share on other sites More sharing options...
steve200b Posted June 1, 2014 Author Share Posted June 1, 2014 Thanks for the feedback I will change the balancer and see what happens this time Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7300183 Share on other sites More sharing options...
ido09s Posted June 2, 2014 Share Posted June 2, 2014 not the first one i have seen and of all the ones i have seen they have had external oil pumps. Must just be a weak spot in the standard crank that doesnt like the added pressure of a oil pump belt Link to comment https://www.sau.com.au/forums/topic/443843-broken-crank/#findComment-7300465 Share on other sites More sharing options...
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