Installing rockers need quick help
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,183
Likes: 265
From: Virginia
Installing rockers need quick help
I am reinstalling my rockers and making sure I torque them down with the lifter on the cam’s base circle. My confusion is that so far the first three bolts take about 1 1/8 turns to get to 22ft lbs but these past two bolts (for ex cylinder 4 intake) literally only took 1/4 of a turn to hit 22ft lbs. I have double checked and made sure it was off lobe also... the pushrod is seated properly in the rocker and I don’t see any debri in the bolt hole. I used the eoic method and also used an adjustable pushrod to verify its on the base circle. Someone educate me.
Burning Brakes
Joined: Jun 2017
Posts: 760
Likes: 242
From: All Over The Place
Did you install new lifters as well? I had no issues on my LS1 when installing 1.8 comp cams 1.8 rollers and tick pushrods. Turned the engine by hand quite a bit in the process. No problems thus far.
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,183
Likes: 265
From: Virginia
I had a shop do my cam install recently and new ls7 lifters were installed. I swapped the pushrods out for longer ones to see if it helped valve train noise but it didn’t help so I’m putting the 7.4’s back in but I’m torquing them properly this time instead of just going down the line tightening them. Should all the rockers bolts turn about the same number of turns? I got a little over one full turn on some. I can see why others would only take a quarter of a turn, or less
Burning Brakes
Joined: Jun 2017
Posts: 760
Likes: 242
From: All Over The Place
Turns varied for mine as well. I did 7.4 ticks, though I have yet to do the cam. Going to do heads, cam, lifters, C5R chain all at once. If you gradually torqued down, they should be fine. As I stated previous, no issues on my end. And I have driven the car.
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,183
Likes: 265
From: Virginia
So it’s normal for some bolts to turn more than others even if on the base circle of the cam?
Burning Brakes
Joined: Jun 2017
Posts: 760
Likes: 242
From: All Over The Place
Was on mine. I just took my time in torqueing down to allow the pushrods to seat slowly. Hand cranked the engine a lot in going through the process. Also, don't be alarmed on the first 10-15 seconds at start up. It will sound crazy as a garment factory full of sewing machines going at full pedal!
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,183
Likes: 265
From: Virginia
Was on mine. I just took my time in torqueing down to allow the pushrods to seat slowly. Hand cranked the engine a lot in going through the process. Also, don't be alarmed on the first 10-15 seconds at start up. It will sound crazy as a garment factory full of sewing machines going at full pedal!
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Racer
Joined: Feb 2015
Posts: 299
Likes: 33
From: Chambersburg PA
This procedure is right from GM service manual and the only one I'll use. Used it when I installed my cam with no issues.
In number 1 firing position (TDC on compression stroke) torque rocker bolts
Ex 1-2-7-8
In 1-3-4-5
Turn engine 360* (1 full turn)
Torque rockers
Ex 3-4-5-6
In 2-6-7-8
Bolt holes should be free of oil, use thread locker on threads (the blue stuff, not red), a dab of oil on bolt head where it touches the rocker arm bushing. Oil the rocker to pushrod contact point.
Rocker arm torque is 22 lb ft
Valve cover bolts 106 lb in
Spark plugs 11 lb ft.
This procedure was developed by GM for a reason, it works. It is the only one I use. I'm not an engineer so I don't consider myself qualified to change an assembly process put in place by better minds than my own.
Do what you want but this is recommended, simple, and it works.
In number 1 firing position (TDC on compression stroke) torque rocker bolts
Ex 1-2-7-8
In 1-3-4-5
Turn engine 360* (1 full turn)
Torque rockers
Ex 3-4-5-6
In 2-6-7-8
Bolt holes should be free of oil, use thread locker on threads (the blue stuff, not red), a dab of oil on bolt head where it touches the rocker arm bushing. Oil the rocker to pushrod contact point.
Rocker arm torque is 22 lb ft
Valve cover bolts 106 lb in
Spark plugs 11 lb ft.
This procedure was developed by GM for a reason, it works. It is the only one I use. I'm not an engineer so I don't consider myself qualified to change an assembly process put in place by better minds than my own.
Do what you want but this is recommended, simple, and it works.
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,183
Likes: 265
From: Virginia
Was on mine. I just took my time in torqueing down to allow the pushrods to seat slowly. Hand cranked the engine a lot in going through the process. Also, don't be alarmed on the first 10-15 seconds at start up. It will sound crazy as a garment factory full of sewing machines going at full pedal!
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
If using the EOIC method, which isn't necessary, you are bleeding down all the lifters as you turn the motor over. Follow the procedure posted by DVUSz06 and this will likely not happen.
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,183
Likes: 265
From: Virginia
That must have been why mine sounded like hell when I cranked it up, I turned the motor over a lot... not trying to hijack the op’s thread but why would it only take a quarter of a turn to hit 22ft lbs after I got the rocker off lobe?! They all did, after I hand tightened the bolt all the way. 7.4 pushrods measuring approx .088 preload. Btr bolts that came with their trunnion kit but I’m using Straub trunnions. On btr’s website those bolts say (to be used with BTR trunnion kit) I don’t see why it would matter tho so I used them because I don’t have the stock bolts anymore.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I found that it took approximately 1/3 turn to tighten the bolt to 22 lb-ft if the rocker was in contact with the rocker stand. So if you are seeing 1/4 turn, and the rocker was bottomed against the stamd, that sounds about right. However, why was the rocker bottomed? If the lifters were new, then they likely didn't have a lot of oil. If they were bled out, could be the same situation. Normally, if the engine has been run and the lifters are full of oil, when installing the pushrods you will see the valve go down as the rocker is tightened and then the valve spring will close while bleed out the oil in the lifter.
Thread Starter
Melting Slicks
Joined: Nov 2011
Posts: 3,183
Likes: 265
From: Virginia
I found that it took approximately 1/3 turn to tighten the bolt to 22 lb-ft if the rocker was in contact with the rocker stand. So if you are seeing 1/4 turn, and the rocker was bottomed against the stamd, that sounds about right. However, why was the rocker bottomed? If the lifters were new, then they likely didn't have a lot of oil. If they were bled out, could be the same situation. Normally, if the engine has been run and the lifters are full of oil, when installing the pushrods you will see the valve go down as the rocker is tightened and then the valve spring will close while bleed out the oil in the lifter.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
They were brand new ls7 lifters put in about 500 miles ago. I know the lifters had all bled down because I could push down on all the pushrods and they would go down. I assume it’s either where the car sat for a week without being cranked or where I manually turned the crank quiet a bit. So yea they were all bottomed out, all of them took about 1/4 of a full turn to hit 22ft lbs. brand new Kobalt torque wrench so I am assuming it’s pretty accurate.