Just adjusted stock rockers using the #1 and #6 TDC method on Shoebox's website. Tightened until pushrod drug and preloaded half turn. Problem is, when at #1 TDC, 3 and 4 intake and 5 and 7 exhaust are loose enough to take the rocker off the pushrod completely. At #6 TDC, 2 and 7 intake and 4 and 8 exhaust have the same problem.

I'll probably try doing one cylinder at a time tomorrow, but any idea why this might be happening?

 

i just installed 1.6 rockers yesterday. i used the gm service procedure which is identical to what you described except after all lash is gone i made 1 full turn-this is what gm recommended. i have not had any problems yet and the rockers are pretty quiet for 1.6sa roller rockers.

 

Where did you find the gm recommendation, off their LT4 rocker install? Can't be off their stock steel rockers because those are just tightened down all the way (they don't need adjusting).

Hal

 

Try the cylinder by cylinder method - it's a lot better IMHO.

 

You're doing something wrong or if you are relying on the mark on the pulley, it may be incorrectly indexed. If all things are in proper order, any of those procedures work.

 

Here is what I based TDC on. Tell me if I'm wrong in this, as I'm still a newb at setting valvetrain. With the heads off, I got the #1 piston to the top of its stroke. The intake lifters on 2 and 7 were clearly in the up position, and the exhaust on 4 and 8 were clearly up. Based on your website, this would be an indication that #1 is at TDC, correct?

Coincidentally, these are the 4 that are extremely loose after one full crank rotation (should be #6 TDC). Am I flawed in my determination of TDC? Really am looking for wisdom from you guys here. Heads are back on and torqued now, so cannot use piston position any longer, but I made a mark with a sharpie on the crank pulley at 12:00 at my supposed #1 TDC.

 

Hal...did I misunderstand your post?

The LT4 rockers, in an LT4 engine are tightened down and torqued to a specific value. There is a ridge, or a stop, on the rocker studs in an LT4 engine. The stock steel rockers, and aftermarket roller rockers, are adjusted as per the instructions on Shoebox's site.

 

Wht you're looking for is TDC on #1..on the compression stroke of that cylinder. That will be when the #1 piston reaches TDC after the #1 intake valve closes. #6 is at TDC when #1 is...it's just on a different stroke. So, since you've marker your damper to indicate when #1 is at TDC, simply rotate the engine over until #1 intake opens and then closes and bring the mark to position. You'll be at the right place to start the adjustment procedure..

Try that....I think it'll solve the issue.

 

lifters calapsing ?

 

Shouldnt be. Car was runnin great when the heater hose blew.

 

ok first of all, you know for a fact you're at tdc on cyl #1 when both valves are closed, and when the valves on cyl 6 (companion cyl) sort of teeter totter back and forth when the crank pully is turned back and forth w/breaker bar. if your dampner is still indexed correctly, the arrow should be at 12 o clock.
now, according to gm service procedure (from service manual) you can adjust exhaust valves 1,3,4,8 and intake valves 1,2,5,7 so...
back off the valve rocker arm nut until lash is felt in the pushrod. tighten the rocker arm nut until all valve lash is removed. zero lash can be felt by moving the oushrod up and down using thumb and forefinger until there is no movement. when all freeplay has been removed, tighten the valve rocker arm nut 1 additional turn. turn the crankshaft one revolution and now you can adjust exhaust 2,5,6,7 and intake 3,4,6,8.
i know the factory rockers were stamped steel but apparently they still need to be adjusted.
hope this helps

 

If you have your intake manifold off, it makes it a LOT easier to find zero lash because you can just watch until the pushrod starts pushing the plunger down.