New Heads and Cam...
Seasoned HDF Member
Joined: Dec 2005
Posts: 19,929
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From: poway
So you're OK there..
About the only other thing I can think of is that the valve caught the edge inner of the pocket and you didn't see it..
Maybe it was bent on assy? The power loss at the track was due to the tower breaking..
About the only other thing I can think of is that the valve caught the edge inner of the pocket and you didn't see it..
Maybe it was bent on assy? The power loss at the track was due to the tower breaking..
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Seasoned HDF Member
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From: Poolville
Road Master
Joined: Mar 2012
Posts: 1,036
Likes: 994
From: Ohio
Seeing that the shaft wasn't bent because of the way I was able to move the valve up and down in the guide with no springs on it freely I would have to assume that there was piston valve contact but it was minimal. I think @Ohio HD was right.. It's possible that the lifters did pump up putting that much more lift on them possibly even to the point of possible coil bind or just barely touching e position....
Actually it was @harpwrench that brought that to light. but I agree with him.
Grand HDF Member
Joined: Sep 2022
Posts: 4,473
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From: Florida
Too me It looks like either the bolts stretched or they were not tightened down. One trick I have always put into practice is to ALWAYS clean all threads and thread holes before assembly. (Especially aluminum) Sometimes the residue of lock tight that compacts in the threads can lead one to believe its tightened down correctly. Not saying it was an error on assembly or manufacturing.. no clue. Just stating some obvious things.
Seasoned HDF Member
Joined: Dec 2005
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From: poway
Seeing that the shaft wasn't bent because of the way I was able to move the valve up and down in the guide with no springs on it freely I would have to assume that there was piston valve contact but it was minimal. I think @Ohio HD was right.. It's possible that the lifters did pump up putting that much more lift on them possibly even to the point of possible coil bind or just barely touching e position....
Now thinking about this, it may be correct. Normally with good design, the springs will never allow the lifter to pump over 0 lash.. The problem was that the bolts were loose and the tower started flexing and maybe crack. This allowed on the exhaust stroke for the intake lifter to be over regular lash and an when it came time to open, the exhaust was closing and the intake opened early.. Hitting the poston.. The tower may have cracked when the valve hit or before. Don't know.
That's my braindead guess..
Road Master
Joined: Jan 2024
Posts: 808
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From: Trinidad
a slackened bolt on the rocker housing would cause it to crack due to uneven forces. The only issue I am seeing is why if there was pv/vv contact how is there no evidence in terms of markings and damage.
Seasoned HDF Member
Joined: Dec 2005
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From: poway
Correct on the first part. I'm sure the towers flexed. The reason why you don't see a contact mark is that the impact was distributed..
The only other possible reason would be if Uri Geller was close by..
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From: New Hampsha
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Seasoned HDF Member
Joined: Mar 2010
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From: Poolville
I will say that about a week before the support plate broke to the point I'm at now, the motor did develop a slight tick that at first I thought was lifters going south but it was on the left side of the motor.. I actually thought maybe my compensator or chain adjuster was going out and never looked into it till now. If I would've look into it sooner I would not be in this situation..
As for pulling the piston to check for damage, I would think either a bent pushrod or collapsed lifter would occur before a cracked piston.. I think I'm good there..
As for pulling the piston to check for damage, I would think either a bent pushrod or collapsed lifter would occur before a cracked piston.. I think I'm good there..