Pushrod Length ?
03-01-2009, 06:57 PM
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Pushrod Length ? Hey guys.
My lifters on my new motor have been making noise ever since day one. They are comp OEMs.
I am running the stock heads and FM14 cam with stock headgaskets. On the previous motor I was running with 7.4 pushrods. When that motor let go I had a rebuild done with forged pistons and rods, stock cubes. The block was decked however I can't remember how much... I know it was not much just enough to clean it up and level it out. Is it possible I might need longer or shorter pushrods and this could be the cause for this noise? The motor has been fine for 5k miles or so... just noisy.
My lifters on my new motor have been making noise ever since day one. They are comp OEMs.
I am running the stock heads and FM14 cam with stock headgaskets. On the previous motor I was running with 7.4 pushrods. When that motor let go I had a rebuild done with forged pistons and rods, stock cubes. The block was decked however I can't remember how much... I know it was not much just enough to clean it up and level it out. Is it possible I might need longer or shorter pushrods and this could be the cause for this noise? The motor has been fine for 5k miles or so... just noisy.
03-01-2009, 08:30 PM
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It's a consistent thumping... low volume. It's what I would consider somethign that sounds like piston slap but on all cylinders.
03-01-2009, 08:32 PM
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^^^ What he said . An adjustable P/R checker is the proper way checking for the right length P/R's . Most aftermarket cams usually require the p/r to be a little longer than stock due to their smaller base circles as long as the stock deck height and head thickness remain intact . 
03-01-2009, 08:40 PM
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Very doubtful they decked it so much you are bottomong out the lifters. If you were, the valves wouldn't be closing and you would have bigger issues. Since you don't know for sure how much it was decked, it's all a big guessing game from now on. You gotta measure to be sure.
03-01-2009, 08:41 PM
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Very doubtful they decked it so much you are bottomong out the lifters. If you were, the valves wouldn't be closing and you would have bigger issues. Since you don't know for sure how much it was decked, it's all a big guessing game from now on. You gotta measure to be sure.
03-02-2009, 05:02 AM
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I found the build sheet on my motor.
Block was decked .010
To me that doesn't seem like enough to throw off pushrod length THAT much. Is it possible that the noise I am hearing is just my forged diamond pistons making more noise than stock?
Block was decked .010
To me that doesn't seem like enough to throw off pushrod length THAT much. Is it possible that the noise I am hearing is just my forged diamond pistons making more noise than stock?
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03-02-2009, 04:55 PM
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.010 off the head surface adds .010 preload to the lifters which theoretically should help to quiet the ticking sound somewhat. That being said , you still should measure for the proper length pushrods if you want everything to be as good as it can possibly be . It is not hard at all to measure the pushrods , it just takes a little time and patience . I'm running a smaller cam in my car (SEE SIG ) than you have and mine requires 7.425 pushrods and my engine is VERY quiet . 
Hope this helps .
Hope this helps . Last edited by Zitty'sZ; 03-02-2009 at 05:07 PM.
03-02-2009, 05:01 PM
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.010 off the head surface adds .010 prelode to the lifters which theoretically should help to quiet the ticking sound somewhat. That being said , you still should measure for the proper length pushrods if you want everything to be as good as it can possibly be . It is not hard at all to measure the pushrods , it just takes a little time and patience . I'm running a smaller cam in my car (SEE SIG ) than you have and mine requires 7.425 pushrods and my engine is VERY quiet . Hope this helps .
Hope this helps .The more I read about diamond pistons the more I think it's slight piston slap causing the sound I am hearing.
