changing dual springs, necessary to use air ??

**SS SLP2** · 07-09-2012, 07:39 PM

to change springs, how much clearnce on top of piston at TDC ? is it necessary to use air or how deep will the value fall into the cyl>
thanks far much needed help
Johnny

**Wfolsom** · 07-09-2012, 08:06 PM

You have to have air to hold the valve all the way up so you can get the valve locks back on

**pajeff02** · 07-10-2012, 03:20 AM

^^ This. Besides, if you accidentally drop a valve by having the engine in the wrong rotation you'll be pulling a head.

**2002ssslp** · 07-10-2012, 05:19 AM

Don't try it without air. There is not way to hold the valve up to get the locks on without air. If you have over 70k on the clock I would pull the heads and do it right. Check everything, put a fresh cut on the heads ( a little more compression is always good. just tell your pcm that your doing this ) make sure you have no burned valves, clean up the chambers, check the guides and put on new seals and gaskets. A little more work but your car will thank you for years after.

**Smittro** · 07-10-2012, 05:48 AM

Originally Posted by SS SLP2

to change springs, how much clearnce on top of piston at TDC ? is it necessary to use air or how deep will the value fall into the cyl>
thanks far much needed help
Johnny

Oh they will fall in there all the way if you're not careful..

Best way I found over the years personally to find each cylinders TDC after number 1 is to stick a plastic drinking straw into the plug hole.

Then rotate the engine till the straw falls out or nearly does so. Then you're "close enough" to hit the cylinder with air and start spring removel/install.

If you drop a valve even half way, pull the head, don't try to rotate the engine and use the piston to push it back up.

You'll hate it when that happens..

Like the guys said,, you'll be pulling the head and now you'll have possible valve and guide damage to go with it.

IIRC,, your valves (LS1) are like my LQ1 and sodium filled, prolly not the cheapest thing to replace, I know mine are'nt.

Don't forget to index your parts if you plan on reusing things.

Just my .02..

Let us know if you have any questions as you go..