How do you check lifter pre-load?
04-24-2002, 06:40 PM
#1
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How do you check lifter pre-load? Guys,
I am pulling the valve covers off of the car this weekend and checking pre-load, doing a compression check, and changing plugs in an attempt to get my car running better.
My question is, how do you check lifter pre-load?
I am doing this because I installed heads/cam and I want to make sure that the 7.350 pushrod is the one the I should be using (stock pushrods were too long and the valves were staying open.
Thanks,
Scott
I am pulling the valve covers off of the car this weekend and checking pre-load, doing a compression check, and changing plugs in an attempt to get my car running better.
My question is, how do you check lifter pre-load?
I am doing this because I installed heads/cam and I want to make sure that the 7.350 pushrod is the one the I should be using (stock pushrods were too long and the valves were staying open.
Thanks,
Scott
04-24-2002, 09:19 PM
#2
Re: How do you check lifter pre-load? I ask this in PSJ's thread but got no response. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
I was about to post this same question because I want to know too. I will list my idea on it.
Here is my guess: It is based on the amount of turns made when tightening down the rocker after the pushrod will not spin around between your fingers with ease. You take the number of turns (till you hit the 22 ft-lb) and figure out how far down you went based on the thread pitch and bam, you have it.
The thread pitch is in mm I guess so we would need to convert. I just need to know the thread pitch and have someone verify what I posted above. That is my best guess.
TTT
ERic
I was about to post this same question because I want to know too. I will list my idea on it.
Here is my guess: It is based on the amount of turns made when tightening down the rocker after the pushrod will not spin around between your fingers with ease. You take the number of turns (till you hit the 22 ft-lb) and figure out how far down you went based on the thread pitch and bam, you have it.
The thread pitch is in mm I guess so we would need to convert. I just need to know the thread pitch and have someone verify what I posted above. That is my best guess.
TTT
ERic
04-24-2002, 09:24 PM
#3
Re: How do you check lifter pre-load? Mellow yellow posted this back on April 9.
MelloYellow
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Member # 116
posted April 09, 2002 12:31 PM
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Comp sells a nice Dial Indicator and base. The base is magnetic which kinda sucks for us. But there is a convenient hole that you can thread a valley cover bolt thru to hold it down.
You align the dial indicator with the pushrod at the rocker base. 2 ways to measure. Get to zero lash, then set indicator to Zero, then TQ to 22 and measure the change in preload. Or what we found to be easier, TQ to 22, line up the dial indicator, zero out dial then release the bolt and measure change, noting zero lash.
Adjustable pushrod length checkers are a joke. Shim measurements are a PITA too.
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I still think that we could just measure the turns and figure thread pitch without having to have a gauge.
ERic
MelloYellow
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Member # 116
posted April 09, 2002 12:31 PM
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Comp sells a nice Dial Indicator and base. The base is magnetic which kinda sucks for us. But there is a convenient hole that you can thread a valley cover bolt thru to hold it down.
You align the dial indicator with the pushrod at the rocker base. 2 ways to measure. Get to zero lash, then set indicator to Zero, then TQ to 22 and measure the change in preload. Or what we found to be easier, TQ to 22, line up the dial indicator, zero out dial then release the bolt and measure change, noting zero lash.
Adjustable pushrod length checkers are a joke. Shim measurements are a PITA too.
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I still think that we could just measure the turns and figure thread pitch without having to have a gauge.
ERic
04-25-2002, 10:55 PM
#6
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Re: How do you check lifter pre-load? The thread pitch and turns should work I guess, but I've seen people drive themselves crazy that way. The Dial indicator was like $100 I think? Not sure where I'll put the base now that the intake manifold is on..
Here's a link:
http://www.compcams.com/catalog/347.html
Here's a link:
http://www.compcams.com/catalog/347.html
04-26-2002, 11:16 AM
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Re: How do you check lifter pre-load? make sure cam is at base circle, turn in rocker bolt until the pushrod will no longer spin freely, then you should have aprox 1 full turn until the rocker bolt is snug. This isn't EXACTLY precise, but it is close enough when the rocker operates on a cusion of oil.....
