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Post by pauldaf44 on May 18, 2014 16:26:30 GMT
You want to check back through its history and see who last worked on the head, then give them a serious talking to! I was the last to work on the head and the rocker shaft seemed to tighten down fine on reassembly. Studs been replaced and thread locked in place. It appeared to do up ok but I will be checking it with paranoi over the next few days
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Post by spunkymonkey on May 19, 2014 11:23:21 GMT
Yeah, I know you were the last to work on it, Paul, just having a little good-natured dig Obvously something went wrong with the reassembly. We've all had it at one time or another - my worst was a BMW 2500 that lost a valve head because I didn't allow for slack in the timing chain when replacing the head*. The important bit is to try an work out what went wrong so you don't repeat it next time. In this case, common reasons for head and rocker studs / bolts failing include under- or over- torquing (leading to stretch on non-stretch bolts) when fitting, oil or dirt under the pedestal foot, oil, dirt or water in the hole, and forgetting to re-check torque after it's been run up to temp for the first time (things tend to settle as they heat). Also, when re-checking torque, always check it by loosening about 1/4 turn then bringing back up to tightness - never just apply a torque wrench because (a) if it's under torque the sticktion of the threads before they move may well make it seem ok and (b) if it's already over-torque checking like that won't show the problem at all. Where there's more than one bolt / stud do them one at a time so the others hold everything in place. * eta: Yes, even I did make a mistake once
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Post by macplaxton on May 19, 2014 12:14:28 GMT
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Post by spunkymonkey on May 19, 2014 12:41:22 GMT
my worst was a BMW 2500 that lost a valve head because I didn't allow for slack in the timing chain when replacing the head yep, that series of smileys roughly sums up my emotions after finishing the job. 80 miles of huge smiles cos it was running SO much better, apart from an annoying tappet sound but "I'll adjust those when I get back". Then a big bang and a tow home - the tapping sound was one valve just touching a piston. Apparently you need to fit the tensioner on those before you fit the cam sprocket to avoid pulling the cam timing out by a tooth or two as it tensions. If only I'd read ALL the warnings in the manual......
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Post by macplaxton on May 19, 2014 16:09:14 GMT
Many moons ago, I counted required number of links at least three times when putting the cams back in on a Kawasaki GT550 and did exactly the same thing after pretty much the same mileage. Head of valve dropped off and said loose lump holed the piston in two places.
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Post by pauldaf44 on May 19, 2014 18:43:06 GMT
Wish I new for sure what happened. It was the stud that unwound not the nut on it and that wasn't disturbed when the head came off. I reckon most likely it was brightened and damaged the thread
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Post by pauldaf44 on May 19, 2014 18:44:20 GMT
Overtightened even
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Post by pauldaf44 on Jun 17, 2014 13:48:02 GMT
Oooh im a silly boy. Just bought this to go on the disco, after I ripped my standard placcy front bumper off last week. I suspect it will take some effort to do the same to that.
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Post by pauldaf44 on Jun 22, 2014 10:05:19 GMT
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Post by mattsdafs on Jun 22, 2014 10:29:49 GMT
Well done Paul,looks a lot of fun...a shame you broke your disco but sure your have that sorted soon
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