Surge 1 Report post Posted July 18, 2011 Hey guys, Just had the rocker replaced on number 3 exhaust, put less than 2000kms on the fixed motor - then it dropped the valve... literally, the valve end broke off - with a piece of broken stem still attached to the retainer. I haven't pulled the motor apart yet but I'd say the whole thing is poked, which isn't too much of a problem as I have a replacement motor... However wondering what actually causes such a catastrophic failure. I've heard of retainers being damaged and the whole valve to fall into the motor but for half of it to snap? - Any insights as to what can be done to prevent this happening again. Quote Share this post Link to post Share on other sites
pureboiracer 0 Report post Posted July 18, 2011 i would imagine when the rocker broke it hit the valve in a way it didnt like, causing damage to it just at the base of the stem, then this created a weak point that eventually broke off. Quote Share this post Link to post Share on other sites
BM WORLD 1264 Report post Posted July 18, 2011 normally caused by the camshaft being worn down on one of the lobes due to lack of oil services or driven too slowly causing lack of oil pressure in the top of the motor. the camshaft lobe(s) will wear down and go a bit square at the top which cause the valve to shut very fast and will cause the valve head to break off. loud tapping noises normally give this away and just adjusting teh valves clearances or replacing the rocker wont fix it . will require the camshaft to be removed and repaired or replaced. looks a bit like this which then causes this Quote Share this post Link to post Share on other sites
Surge 1 Report post Posted July 18, 2011 Cheers for the replies and the pics. I'll check the state of the camshaft when I'm back in at work and see how it looks compared to the one you posted Brent. Quote Share this post Link to post Share on other sites
