Knock due to lifter failure???
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Staging Lane
Joined: Jan 2010
Posts: 65
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Knock due to lifter failure??? I recently installed on my 67c10 a recently rebuilt stock 2005 carb ls2(vette) and a 700r4, the engine really runs great!!!... but(there is always a but..) long story short we rev the engine to almost 6k then shift to 3rd and slow down.. then suddenly a not friendly knock appeared.... looked at oil preasure, it was OK, no oil smell, no smoke from the exhaust, still plenty of power, all seem normal except for the noise... then check for metalic particles on oil an nothing... took a valve cover and all rockers look fine, then check of one was loose, nothing.. then check for pushrods and one of them was loose, you can move it up and down easily.. the valve was compeltely closed, took the rocker and pushrod and all where fine.... Can I assume a lifter collapse? maybe the cam also suffered some damage? I know I have to remove the head to have a proper look on possible damage.. but your opinions and knowledge will help..
Thanks!!!
Thanks!!!
If it was the cam lobe your oil would look like metallic paint or at least show signs of metal, so if you're not seeing metal in the oil then my first guess would be collapsed lifter. As far as damage/pitting done to the cam due to lifter collapse, It's possible but you won't know until you tear into it.
Depending on the severity of a lifter collapse, you could also find metal shavings and shrapnel.
By first determining the nature of the knock (when it occurs with respect to throttle and whether it skips or is consistent), you can start to rule out a few general things. Also, be sure to distinguish between a tick and a knock, with the first being higher pitched and the latter being lower.
By first determining the nature of the knock (when it occurs with respect to throttle and whether it skips or is consistent), you can start to rule out a few general things. Also, be sure to distinguish between a tick and a knock, with the first being higher pitched and the latter being lower.
