Valve train noise

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chuckl1966

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My 318 has a valve train noise. The engine was just rebuilt. Installed new Purple shaft cam. #5 intake valve train makes noise. I replaced lifter, pushrod and rocker arm. Checked oil port in lifter bore to see how much oil, if any, it was getting to lifter, checked ok. After engine is up to temp, the noise goes away. I’m thinking worn lifter bore, which would mean no repair? Any other thoughts? I’ll take any and all help on this one.
 
I bought a MP cam w/lifters kit and had 3 lifters that wouldn`t pump up. I had to take them apart , clean them well and reinstall. I had the same noisy valvetrain which is better now, but still makes some racket even with roller rockers.
 
chuckl1966 said:
My 318 has a valve train noise. The engine was just rebuilt. Installed new Purple shaft cam. #5 intake valve train makes noise. I replaced lifter, pushrod and rocker arm. Checked oil port in lifter bore to see how much oil, if any, it was getting to lifter, checked ok. After engine is up to temp, the noise goes away. I’m thinking worn lifter bore, which would mean no repair? Any other thoughts? I’ll take any and all help on this one.
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I'm guessing that you've got the stock valve train a hydraulic lifters. You may not have enough preload on No. 5 lifter. When the push rod and valve are up to temperature the tapping would go away. When the engine is cold roll it over till number 5 piston is at TDC. There should be zero clearance at both intake and exhaust valve stem to rocker. :evil2:
 
chuckl1966 said:
If there is clearance will an adustable pushrod fix the problem?
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if you're absolutely sure that the lifter is pumped up then yes, but you gotto ask yourself why is the #5 valve train acting different than all the other valves, rockers and lifters.

What type of valve train are you running, stock or adjustable and who's.
 
Well, it's the stock rocker arm assy. I may need to do more research on lifter preload. I just can't fully explain the noise going away after the engine come to temp.
 
chuckl1966 said:
Well, it's the stock rocker arm assy. I may need to do more research on lifter preload. I just can't fully explain the noise going away after the engine come to temp.
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As the engine gets to temperature the push rod and valve stem will grow in length and physically get longer, I'm guessing .004"-.010" but I've never measured it, and this will take up any slight clearance between the valve stem and rocker arm. The actual amount of growth is based on temperature and material (thermo growth of aluminum and steel are different) and this is why there is a cold clearance between the rocker arms and valve stems of engines with solid lifters. :evil2:
 
Did you put a larger diameter pushrod in the engine? Some guys have experienced clearance problems where the pushrod rubs the head.
 
No. Standard, stock, same as. I just had a thought, lets see if anyone has tried this. How about putting an adjustable rocker arm on just that valve? The "cut to fit" push rods seems to me to be a hit and miss proposition. I'll start looking into it. May be a wild thought, but it's a thought.
 
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