How do you determine the correct length pushrod?
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TECH Apprentice
Joined: Dec 2001
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From: CA
How do you determine the correct length pushrod? I'm using 7.40" pushrods with the TR224 and ARE S2 heads, and I want to check if that is the correct length. If it's not, I'm going to get the adjustable length pushrod. But still, I'm not sure how to check for the correct length. Does anyone have good info on this for dummies?
I found this and it looked to be good info :
http://www.compcams.com/information/Products/Pushrods/
But I don't know exactly how to do this : "What is correct valve train geometry? When the rocker arm roller tip rolls from the intake side of the valve tip, across the center of the tip (at approximately mid-lift), to the exhaust side of the valve tip (at full lift) and back. See Diagram A."
How do you spin the cam to make the rocker roller roll in the first place? And what side is the intake side and what side is the exhaust side?
Can anyone give me some information that is specific to the LS1?
I found this and it looked to be good info :
http://www.compcams.com/information/Products/Pushrods/
But I don't know exactly how to do this : "What is correct valve train geometry? When the rocker arm roller tip rolls from the intake side of the valve tip, across the center of the tip (at approximately mid-lift), to the exhaust side of the valve tip (at full lift) and back. See Diagram A."
How do you spin the cam to make the rocker roller roll in the first place? And what side is the intake side and what side is the exhaust side?
Can anyone give me some information that is specific to the LS1?
Re: How do you determine the correct length pushrod? For info on the TR224 and pushrod sizing see
https://ls1tech.com/ubb/cgi-bin/ulti...c;f=1;t=004309
I did not follow the Comp Cams instructions when I swapped cams, but what they are basically saying is to center the contact pattern of the rocker on the valvestem tip.
You can use a marker on the tip of the valvestem so you can see the contact pattern. Assemble valve train and rotate the engine using the harmonic balancer bolt. Adjust the checking pushrod till the contact pattern of the rocker tip is centered on the valvestem.
The Comp Cams info is backwards. (Doesnt effect results though)
From Comp Cams Pushrod Length & Rocker Arm Geometry: "When the rocker arm roller tip rolls from the intake side of the valve tip, across the center of the tip (at approximately mid-lift), to the exhaust side of the valve tip (at full lift) and back. See Diagram A."
Should read: "When the rocker arm roller tip rolls from the exhaust side of the valve tip, across the center of the tip (at approximately mid-lift), to the intake side of the valve tip (at full lift) and back. See Diagram A."
I/E side refers to the side of the head each manifold is on. I=left E=right in their pic.
https://ls1tech.com/ubb/cgi-bin/ulti...c;f=1;t=004309
I did not follow the Comp Cams instructions when I swapped cams, but what they are basically saying is to center the contact pattern of the rocker on the valvestem tip.
You can use a marker on the tip of the valvestem so you can see the contact pattern. Assemble valve train and rotate the engine using the harmonic balancer bolt. Adjust the checking pushrod till the contact pattern of the rocker tip is centered on the valvestem.
The Comp Cams info is backwards. (Doesnt effect results though)
From Comp Cams Pushrod Length & Rocker Arm Geometry: "When the rocker arm roller tip rolls from the intake side of the valve tip, across the center of the tip (at approximately mid-lift), to the exhaust side of the valve tip (at full lift) and back. See Diagram A."
Should read: "When the rocker arm roller tip rolls from the exhaust side of the valve tip, across the center of the tip (at approximately mid-lift), to the intake side of the valve tip (at full lift) and back. See Diagram A."
I/E side refers to the side of the head each manifold is on. I=left E=right in their pic.
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Joined: Mar 2002
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From: Chicago Land
Re: How do you determine the correct length pushrod? So there is no way to determine the correct length before the install. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
Re: How do you determine the correct length pushrod? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by sited12:
<strong>So there is no way to determine the correct length before the install. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yes there is a correct way.
Follow the Comp Cams article, that will tell you how to do it. IF your pushrod is wrong it will not do it that way, the Hi Tech Adjustable pushrods are awesome!
I prefer to have it roll from the middle at the top to exh of the valve tip at mid lift back to the middle of the valve at full lift. This is a Warren Johnson thing.
Bret
<strong>So there is no way to determine the correct length before the install. <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yes there is a correct way.
Follow the Comp Cams article, that will tell you how to do it. IF your pushrod is wrong it will not do it that way, the Hi Tech Adjustable pushrods are awesome!
I prefer to have it roll from the middle at the top to exh of the valve tip at mid lift back to the middle of the valve at full lift. This is a Warren Johnson thing.
Bret
