Advice on Valve Spring Change Procedures
11-24-2011, 07:12 PM
#1
Advice on Valve Spring Change Procedures
I am in the process of replacing stock valve springs with new stock valve springs in a 2002 Z06. It is completely stock with 55k miles and I have no performance problems whatsoever. I have done some LT1s before but this is my first LS. A few questions:
1) I want to use the TDC method to prevent the valves from falling into the cylinder when I release the lock. Using the rockers and the crank position, how do I determine TDC for each cylinder?
2) What is the best method for adjusting the preload without the engine running and what is the spec for turns past zero lash?
3) What is the torque spec for the rocker arms?
I plan on using stock GM valve springs, inspect the seats/retainers/locks, replace the valve seals with stock GM and replace the valve cover gaskets with Felpro.
4) Any additional recomendations or deviations form this? Am I missing any critical steps in the procedure?
5) I have searched for a complete procedure/post using these methods, but I was unable to find one. Are there any good posts?
6) Is it worth gaging the install height and shimming to get them all exactly the same preload (I think the shims go down to 0.008 in)?
1) I want to use the TDC method to prevent the valves from falling into the cylinder when I release the lock. Using the rockers and the crank position, how do I determine TDC for each cylinder?
2) What is the best method for adjusting the preload without the engine running and what is the spec for turns past zero lash?
3) What is the torque spec for the rocker arms?
I plan on using stock GM valve springs, inspect the seats/retainers/locks, replace the valve seals with stock GM and replace the valve cover gaskets with Felpro.
4) Any additional recomendations or deviations form this? Am I missing any critical steps in the procedure?
5) I have searched for a complete procedure/post using these methods, but I was unable to find one. Are there any good posts?
6) Is it worth gaging the install height and shimming to get them all exactly the same preload (I think the shims go down to 0.008 in)?
11-24-2011, 10:06 PM
#2
Le Mans Master
The LS motor is different than a LT1. Go to LS1HowTo.com and read about it, just make sure when you torque the rockers you follow the service manual. Here's the sheet?
11-25-2011, 12:40 AM
#3
I am in the process of replacing stock valve springs with new stock valve springs in a 2002 Z06. It is completely stock with 55k miles and I have no performance problems whatsoever. I have done some LT1s before but this is my first LS. A few questions:
1) I want to use the TDC method to prevent the valves from falling into the cylinder when I release the lock. Using the rockers and the crank position, how do I determine TDC for each cylinder?
2) What is the best method for adjusting the preload without the engine running and what is the spec for turns past zero lash?
3) What is the torque spec for the rocker arms?
I plan on using stock GM valve springs, inspect the seats/retainers/locks, replace the valve seals with stock GM and replace the valve cover gaskets with Felpro.
4) Any additional recomendations or deviations form this? Am I missing any critical steps in the procedure?
5) I have searched for a complete procedure/post using these methods, but I was unable to find one. Are there any good posts?
6) Is it worth gaging the install height and shimming to get them all exactly the same preload (I think the shims go down to 0.008 in)?
1) I want to use the TDC method to prevent the valves from falling into the cylinder when I release the lock. Using the rockers and the crank position, how do I determine TDC for each cylinder?
2) What is the best method for adjusting the preload without the engine running and what is the spec for turns past zero lash?
3) What is the torque spec for the rocker arms?
I plan on using stock GM valve springs, inspect the seats/retainers/locks, replace the valve seals with stock GM and replace the valve cover gaskets with Felpro.
4) Any additional recomendations or deviations form this? Am I missing any critical steps in the procedure?
5) I have searched for a complete procedure/post using these methods, but I was unable to find one. Are there any good posts?
6) Is it worth gaging the install height and shimming to get them all exactly the same preload (I think the shims go down to 0.008 in)?
Second....I would forget the TDC method....its tough and unreliable (very hard to compress the spring enough to get the locks off and on when the valve drops...even just a little. You will need all of the height the valve has to offer...the coil will bind very quickly). Just get yourself a spark plug compressed air hose...there like 7 bucks at Harbour Freight. Thread it in the spark plug hole in which your working on...slowly apply the air...the cylinder will rotate to BDC (go slow to keep from slamming it down) at this point get your spring compressor tool and compress the spring and remove the locks. A pencil magnet works well in retrieving the locks from around the retainer. Reverse the process and remove the air and then then hose threaded in the spark plug hole and go to the next cylinder.
Third...the preload is nothing you will need to worry about untill you have changed either the base circle of the cam or the head deck height. And it sounds like you javen't changed either. So...if it is a stock long block just put the pushrod back in and tighten the rocker to 22ft lbs. There are difference.of opinions on the torque procedure...some say just torque and be done others will tell you to torque on the base circle..aka and closed valve..that way your not working against the lift of the lobe. I have done it both ways and did not notice a.difference either way.
Forth...the valve cover gaskets done not need to be replaced..unless they are damaged. They are O rings and will last forever.
Fifth....the peload on the vavle spring is not nessasary on the factory spring...juat duplicate what you remove. If you go with an aftermarket spring they will have a recomended installed height. Most of the LS aftermarket spring come.ready to go..meaning no shim nessasary. If you want you can check you compressed height a see.what your pressure is and adjust from there but.....for this application I feel it is not nessasary.
Thanks....and good luck with your project...feel free to ask more questions. And this was all typed from my phone..so sorry for the errors
11-25-2011, 07:35 AM
#4
Is anyone else having trouble with the LS1HowTo.com? I try to go to that web site and I get a weird generic page that I don't believe is correct. It is as if the site is gone.
11-25-2011, 08:54 PM
#6
ls1howto does seem to be history, but there is a mirror site here
http://web.archive.org/web/201107160.../ls1howto.com/
http://web.archive.org/web/201107160.../ls1howto.com/
