LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

pushrod length

Thread Tools
 
Search this Thread
 
Old Feb 24, 2011 | 10:28 PM
  #1  
1badasZ's Avatar
Thread Starter
Registered User
 
Joined: Jan 2001
Posts: 870
From: Florence Mississippi
pushrod length

im not anywhere near advanced enough to check geometry n stuff to find the exact pushrod length. for what i've done do i need stock length, longer or shorter? stock block, heads milled .010, crane springs, impala head gaskets, and comp extreme 230/236 .544/.555 with 1.6 rr
Old Feb 24, 2011 | 11:02 PM
  #2  
henryz28's Avatar
Registered User
 
Joined: Jul 2006
Posts: 974
Re: pushrod length

Stock is 7.2" lloyd told me to run 7.1" if I did not want to measure the pushrod length. So I would think you would be good to go with 7.1" pushrods if you don't want to measure the length.
Old Feb 24, 2011 | 11:29 PM
  #3  
MachinistOne's Avatar
Registered User
 
Joined: May 2004
Posts: 2,001
From: Bay Area, CA
Re: pushrod length

If you're not capable of checking for PR length you shouldn't be touching the motor, it's as simple as that.

The procedure is cheap and easy, and there's plenty of write-ups on the internet of how to do it properly....no excuses

You really want lost lift and quickly worn out guides by possibly getting the wrong PR length?
Old Feb 24, 2011 | 11:41 PM
  #4  
henryz28's Avatar
Registered User
 
Joined: Jul 2006
Posts: 974
Re: pushrod length

PR length is something that you need to check to get the EXACT length. Use an adjustable PR checker and start at 7.100" and adjust the length until you get the wear pattern most centered in the valve. Go .050" shorter and watch the wear pattern move. If it gets worse, go .050 longer. It could be anywhere from 7.00 to 7.250 depending on everything done but a 7.100" (Trik Flow 21407100) is what I suggest for people that do not know how (or do not wanna take the time) to do this.

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.

That is my message from lloyd, but I did not post the pics
Old Feb 25, 2011 | 05:25 AM
  #5  
Guest47904's Avatar
Guest
 
Joined: Sep 2004
Posts: 0
If nothing else, check what you have

This is the best information available

http://www.compcams.com/Pages/417/va...-geometry.aspx

In a nut shell, you want the contact to be as close to the center of the valve the entire time.



Start with the rods you have and check it. Then decide if the "tester" you need is longer or shorter based on the movement of the arm.
Old Feb 25, 2011 | 09:12 AM
  #6  
1badasZ's Avatar
Thread Starter
Registered User
 
Joined: Jan 2001
Posts: 870
From: Florence Mississippi
Re: pushrod length

Ok sounds easy enuff just wasn't sure how to go about it. Can I use 7/16 studs and guide plates on my heads without having to machine anything?
Old Feb 25, 2011 | 01:22 PM
  #7  
bowtiedad_z28's Avatar
Registered User
 
Joined: Jun 2008
Posts: 204
From: Rochester, Indiana
Re: pushrod length

Yes you can.
Old Feb 25, 2011 | 01:24 PM
  #8  
bw_hunter's Avatar
Registered User
 
Joined: Jul 2002
Posts: 1,942
From: Kissimmee, Fl, USA
Re: pushrod length

Originally Posted by 1badasZ
Ok sounds easy enuff just wasn't sure how to go about it. Can I use 7/16 studs and guide plates on my heads without having to machine anything?
Yes, you can. the stock 3/8" studs are7/16" in the head...
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
13qtr
Parts For Sale
24
Oct 28, 2016 08:11 PM
9t4lt4z28
LT1 Based Engine Tech
1
Oct 2, 2015 10:28 AM
sleeperZ96BT
Parts For Sale
5
Sep 9, 2015 08:28 AM
realistyc
Cars For Sale
4
Jul 28, 2015 07:32 PM
94Form
LT1 Based Engine Tech
12
Jul 17, 2015 10:56 PM




All times are GMT -5. The time now is 04:24 AM.