ok just rebuilt a 2002 5.3. shaved the heads .030 did not know i needed to shave the push rods. taking the rocker arms back off to put shorter pushrods now for some reason they are about a quarter inch too long. ok like the little clip that holds the lifer guts in broke and pushing out so far its the hole bank. any ideas before i pull the heads? they are new lifters

 

"any ideas before i pull the heads?"
The ideas come AFTER you take the heads off and post details and pics.

 

Sounds kinda like an assembly problem. Like, the rocker stands in upside down or turned around backwards or whatever you want to call that (intake side facing the exhaust and vice-versa), or something simple and easily overlooked like that.

 

ok the motor was running but crappy so when i took the rocker arm off to put shorter push rods on . just as soon as i did that the lifter expanded to full lenght and when im puting the rocker arm back on the valve spring compress but the lifter dont move. these are new lifters . is there a way they bleed off?

 

Yup. Run it. In the first few engine cycles, they'll self-adjust.

 

cant the valve hits the piston as I'm tightening down the rocker arm the spring in the lifter won't give so the valve spring moves , it did not do that when before two seconds ago when i took them off. so i replaced old push rods same thing its like the lifter wasnt fully out untill i took the rocker arm off then it extended to the top anf locked full pushed out and refuses to give in

 

Probably not. I don't know what's in your motor of course, butt if it's stock or really even anywhere close, there's SO MUCH p2v clearance that it'll never happen.

Chances are, sitting there with valve spring pressure on them, they'll bleed down overnight or whatever, if you're not gonna crank it right up immediately anyway.

Regardless, it's a total non-issue. Happens to everybody every time with every motor of every kind from every mfr. If it was a genuine problem you'd be hearing AHELLUVALOT more talk about it everywhere.

 

I have to ask, are you sure the cam is on the base circle on whatever rockers you are checking?

 

It's impossible to have the rocker arm stands backwards or upside-down.

 

ok first test seems like it did bleed down. im glad i asked you guys instead of popping heads. so ask what size push rods you would use on this setup. 2002 5.3 with flat top pistons 799 heads that have been millied .030 with the three metal shims head gasket. i know the 7.40 push rods where to long. i can't use the pushrod checker tool this way so i have 7.375 or 7.350 push rods. i dont want a noice engine im thinking the 7.375 push rods would work what do you guys think?

 

Nobody can guess what length you need…you have to measure yourself.

 

yes but this set up has been done lots of times so some one that has done it could recommend something

 

No. It comes down to YOUR measurements on YOUR engine. Simple as that.

 

so if a guy has my same set up 2002 5.3 with flat top pistons and 799 heads millied .030. the three shims head gasket that we wouldnt use the same push rods every thing stock

 

We can guess, if your into that. What’s the compressed thickness of your headgasket?

 

Assembly problem

 

.035. also this engine did start and run but the push rods where to long so when i went to replace them and removed the rocker arm. the lifter cylinder extended fully out . in order to put my shorter push rods in i had to slowly bleed down the lifters, over night to the 7.375 lifters so how could i measure them with out starting all over with preloaded lifters . i have the push rod checker tool but i dont know at what point do i bleed it down to to check the length

 

Let’s start from the beginning here…never mind the shaved heads and .035 headgasket for now.
1. Why do you think the current pushrods are too long…is it because of a ticking noise, or does the truck do something weird when running?
2. What lifter did you use…is it an LS7 variant, meaning you bought simple replacement lifters?

 

when i started it the motor sounded like it had a major cam. multiple miss firing had a mech look at it with a reader and 8.6,2, and 3 misfiring. i replaced all injectors and coils on these cylinders and no different so did a compression check went from 95 one cylinder to 65 another so i took off the rocker arm cover and put number two cylinder top dead center as i could see the rocker arms move and then i slowly backed off the rocker arm and the valve spring came up oo about .020 to .030 i could see it move so thats when he asked me about my heads and shaving them . said you should change your push rods also the valves are staying open . the machine shop didnt think i needed to so any way. thats when i went to remove the rocker arm to put the shorter ones on and all this started lol yea and the lifters i bout oem but went back and looked and say campatible with ls7 but i see a lot of adds that have ls7 in bold so i di believe thie are not the ls7 lifters i know there longer this is what i got Fits Model:

Camaro,Trans Am,GTO,G8,Corvette,GM Truck,CTSV,Silverado,Sierra,4.8,5.3,5.7,6.0,6.2,TB SS,Chevy SS,LS1,LS2,LS3,LS6,LS7,LS9,LQ4,LQ9,L33

Lifters OEM:12499225

Guides Trays OEM:12595365

 

Ummmmm... NO.

On my engine (04 LM7) there's a little rectangular cast-in "feature" on the underside of the stand thing that sort of locates it on the bosses of the heads. The bosses aren't square, so if the stand is put on turned the wrong way, the "feature" holds the stand up off the boss so that it won't sit down flat on the heads.

Guess how I know this.

I have no clue whether ALL of these engines include this feature, butt it's DEFINITELY possible to install those things incorrectly on at least SOME.