Rocker arm install question
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Joined: Feb 2013
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From: Miami, FL
Rocker arm install question
My engine builder measured out preload for my lifter and rocker arm setup (Johnson 2116LSR and YT6670A) and gave me the necessary pushrods (8.000") but gave me everything uninstalled as we've installed the heads after putting the short block back in the car first (2006 Z06).
My question is, do I have to follow the standard valve opening and closing method to install the rocker arms (as if I was measuring preload)?
Or can I just install them to finger tight zero lash and torque down to 25 lb ft (Yella Terra torque spec) at any cam position since I'm no longer measuring for preload?
This is a fully rebuilt engine and it has not been oil primed yet so don't want to turn it over by hand just yet, just wanted to get everything set up before the priming.
My question is, do I have to follow the standard valve opening and closing method to install the rocker arms (as if I was measuring preload)?
Or can I just install them to finger tight zero lash and torque down to 25 lb ft (Yella Terra torque spec) at any cam position since I'm no longer measuring for preload?
This is a fully rebuilt engine and it has not been oil primed yet so don't want to turn it over by hand just yet, just wanted to get everything set up before the priming.
Safety Car
Joined: May 2016
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From: Erlanger, Kentucky
You will want to install and tighten the rocker arm bolts while the lifters are on the base circle of each cylinder. So you will need to rotate the engine for each cylinder to be on the base circle.
You don't want to install and tighten the rocker are bolts when on the lobe of the cam as the increased force can potentially strip out the threads from the head. (And if you have a high lift cam and stronger valve springs, the risk is that much higher).
So you can use the valve opening and closing method and do two cylinders at a time. Rotate 90 degrees, tighten two more cylinders, and so on.
It won't hurt the engine to rotate it by hand for this.
You don't want to install and tighten the rocker are bolts when on the lobe of the cam as the increased force can potentially strip out the threads from the head. (And if you have a high lift cam and stronger valve springs, the risk is that much higher).
So you can use the valve opening and closing method and do two cylinders at a time. Rotate 90 degrees, tighten two more cylinders, and so on.
It won't hurt the engine to rotate it by hand for this.
Thread Starter
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Joined: Feb 2013
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From: Miami, FL
Thank you.
So turning the engine by hand should be fine even with no oil ran through it yet? Fresh rebuild with new crank, pistons, rods, etc.
So turning the engine by hand should be fine even with no oil ran through it yet? Fresh rebuild with new crank, pistons, rods, etc.
Last edited by Layzee; Aug 15, 2022 at 11:21 AM.
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Safety Car
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From: Erlanger, Kentucky
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2021 C6 of the Year Finalist - Modified
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Thread Starter
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Joined: Feb 2013
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From: Miami, FL
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From: SW Florida
2021 C6 of the Year Finalist - Modified
Not at all ... just 'tap' the wire between those two contact points and it will rotate the engine not even a 1/4 of a turn.
Tap Tap Tap until you get each lifter on the bottom of the cam's base circle.
Nothing to it ...
Tap Tap Tap until you get each lifter on the bottom of the cam's base circle.
Nothing to it ...
Burning Brakes
Joined: Jun 2015
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From: Shelbyville Kentucky
The reason they want the cam on the base circle when tightening the rocker is to prevent pulling the threads out of the rocker stud. I found this isn't an issue with stock-ish valve springs. But if you have some humdingers in there you better do the base circle thing.
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Melting Slicks
Joined: Nov 2011
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From: Virginia
If I had to do this again I would prob do as mentioned earlier and bump the starter by using the paper clip in the starter relay method. If you don’t torque the bolts while on the base circle of the cam I would go slowly and then after a short drive check the torque on all the bolts. I’ve not tried it but supposedly you can remove the plugs and put a socket on the alternator pulley.
Intermediate
Joined: Jul 2020
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From: WV
You can make a starter bump with a momentary switch and two wires and plugs to attach to starter and battery...long enough wires to reach where you are working at. Just bump engine a necessary. I have used one I made for years on multiple engines.