pushrod length
pushrod length i just installed a a custom ground cam from comp cams with a 588 598 112lsa and i ordered 7.425s for rod and i got a ticking noise from the valve covers just wondering if it is the wrong size of pushrod maybe i need to go to 7.400 stock length. I called local tuning shop and he said he always goes with 7.400 rods, maybe i need to let it warm up a bit and wait for the oil to get up there would that hurt anything. I have a pushrod length checker but have no clue how to use it anyone give me some tips are advice on what i should do......
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Joined: Dec 2001
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From: Bergen County, NJ
Check several intake and exhausts with the checker and use your best average. .080 to .100 is what is recommended for a quiet setup so the 7400s would be better based on that one measurement.
Launching!
Joined: Jan 2008
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From: Westminster, Md
I think you shouldn't have to change the pushrod length if you are using stock rockers and stock lifters. See, all you are changing is the lift and duration of the cam...which I don't believe will effect your pushrod length. See, I am about to install LS7 lifters and Harland Sharp 1.7 non-adjustable rockers. The point of this is that I found out that the LS7 lifters are a little longer than stock ones, affecting the legnth of the pushrod. As well, I don't know how the Harland Sharps will sit on the springs and what not. This is why I have ordered two sets of chromeoly pushrods 7.4 and 7.35 along with a pushord length checker so I do the change correctly and use the right length pushrod. If I find that I need the 7.35's I will gladly GIVE you my chromeoly 7.4's from TSP.
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From: BFE
Are you on stock LS1 lifters?
How did you install rockers?
Are your springs at proper height?
As per your measurement 7.425s seem about perfect on LS1 lifters, unless there is something else we do not know.
How did you install rockers?
Are your springs at proper height?
As per your measurement 7.425s seem about perfect on LS1 lifters, unless there is something else we do not know.
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yes i am on stock ls1 lifters and torqed my rockers down to 22 ft lbs and yes my springs are at proper height. but they still tick coming from the valve cover sounds like, so i didnt even let it warm up maybe for 1-2 min ran and i shut it off thinking something was wrong
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Verdad Gallardo Are you saying the noise was immediately after a cam swap? It took several minutes for mine to quiet down after the swap so it may be the lifters just haven't pumped up yet.
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From: BFE
When you installed the rockers did you just trq all at 22ft/lbs and that is it or did you do the base circle on TDC following firing sequence?
See if you do not do proper install some of your rockers can be loose. When rocker is tightened on base circle, that is the smallest lobe area. If the rocker is tightened on another area of cam ramp it will be loose once reaching base circle and can have that ticking noise
See if you do not do proper install some of your rockers can be loose. When rocker is tightened on base circle, that is the smallest lobe area. If the rocker is tightened on another area of cam ramp it will be loose once reaching base circle and can have that ticking noise
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From: BFE
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taken from the cam guide sticky on the interneal engine section:
How To Verify Proper Valve Train Geometry
from Holly.com
The following is a method of verifying proper valve train geometry. After you have estimated the required pushrod length using a Pushrod Length Checker, use this method to verify that the valve train geometry is correct (using the rockers you are using in your engine):
1
The first step is to install a solid lifter and an adjustable pushrod. Mark the tip of the valve with a marker
2
Install your rocker arm and set it up with zero lash.
3
Rotate the crankshaft clockwise several times. Remove the rocker arm. The contact pattern of the rocker tip will be where the marker has been wiped away from the valve tip. The pattern should be centered on the valve tip, and as narrow as possible. If it is not, experiment with varying the pushrod length to yield the best pattern.
4
Pushrod Too Long: Notice how the pattern is wide, and shifted to the exhaust side of the valve tip.
5
Pushrod Too Short: Notice how the pattern is wide, and shifted to the intake side of the valve tip.
6
Pushrod Length Correct: Notice how the pattern is narrow and is centered on the valve tip.
How To Verify Proper Valve Train Geometry
from Holly.com
The following is a method of verifying proper valve train geometry. After you have estimated the required pushrod length using a Pushrod Length Checker, use this method to verify that the valve train geometry is correct (using the rockers you are using in your engine):
1
The first step is to install a solid lifter and an adjustable pushrod. Mark the tip of the valve with a marker
2
Install your rocker arm and set it up with zero lash.
3
Rotate the crankshaft clockwise several times. Remove the rocker arm. The contact pattern of the rocker tip will be where the marker has been wiped away from the valve tip. The pattern should be centered on the valve tip, and as narrow as possible. If it is not, experiment with varying the pushrod length to yield the best pattern.
4
Pushrod Too Long: Notice how the pattern is wide, and shifted to the exhaust side of the valve tip.
5
Pushrod Too Short: Notice how the pattern is wide, and shifted to the intake side of the valve tip.
6
Pushrod Length Correct: Notice how the pattern is narrow and is centered on the valve tip.