haole_boySS

iTrader: (1)

Use the air compressor. It is much safer. Just be sure that you take the schrader valve out of the air line before putting it in the spark plug hole. If not you wont blow air in the cylinder and thus you will drop a valve when the spring is removed.

Hope this helps

Classic

iTrader: (3)

It is much easier to just bring the piston up and change the springs. All you have to do is just turn the motor over by hand - use your big torque wrench or breaker bar and turn the crank by hand. I have stock heads never been off the car and my valves didn't even come close to slipping out doing it this way.

Visceral

iTrader: (1)

Ive done it both ways. I sorta prefer the TDC method because getting that air hose in the spark plug sockets in the back two cyl's can be a task. With the TDC method though, you really do get nervous that first cylinder ;-) from then on its just a matter of going by (and checking like 4 extra times that you are correct) the firing order.

chris

MOBE

How do you know when any given cylinder is at TDC?

Sorry if thats a dumb question! <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" /> I've never done it either.

JimMueller

iTrader: (9)

So where do I find the procedure to put the various pistons at TDC?

Biochem

Just stick a pushrod in the intake (or exhaust) hole and when it is all the way down, the piston should be at the top of its stroke...

cy

I did both with my cam install b/c i got tired of the compressor turning on and off (i couldn't get the spark plug attachment to seal completely). I didn't even try to figure out the firing order and hope i turned the crank enough, i just put the pushrods in and watched until those were both all the way down. Then i had someone help me and hold the valve (or i put a wrench on the end just to hold it from fallin), i compressed the spring and slowly pushed the valve down while holding it until it hit the piston...safe that way.

Both are completely safe ways, you just have to make sure not to screw up <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

JimMueller

iTrader: (9)

I've heard it may be easier to do my next valvespring change by just putting each piston at TDC instead of keeping the valves up with compressed air.

Experiences? Writeups? I don't know how to put pistons at TDC, but I do have a 99 Helms manual (although my car is a 98).

TIA!

Hoodshaker

The LS1 has a 1-8-7-2-6-5-4-3 firing order which I got from here. If I remember correctly, #1 is at TDC when the the timing marks are pointed at each other (crank an 12:00, cam at 6). Change intake and exhaust on #1. From there all you have to do is rotate the crank 90 degrees clockwise to bring the next in order to TDC. (car must be out of gear, I wasn't strong enough to burn rubber using my Craftsman wrench <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> ) I found this to be much easier and quicker than the compressor, even though this was a desperation move after I couldn't get a good seal with the spark plug attachment and then it fell behind the motor mount, never to be seen again. I would definitely use this method again.

2001 Pewter WS6

iTrader: (43)

I used the top dead center method. If yo are changing the cam, use the Mr Baskets method for the cam swap and spring change. It worked great.

JimMueller

iTrader: (9)

No new cam, unfortunately. I have inadequate PVC with the G5X2. <img border="0" title="" alt="[Frown]" src="gr_sad.gif" />

Ramair346

So to kick a dead horse, all I have to do is put the pushrods in and turn the motor over by hand. The pushrods that are the lowest or farthest down, are where the piston is TDC? This method has been utilized and is safe? G5X2 goes in Saturday! All the experts, please confirm that THIS method is safe and will work. Thanks!