Vortec valve lash adjustment question?

[Black Knight]

I'm trying to adjust the valves on a set of vortec's I just installed and it seems like they tighten up before I get all the lash out of the push rods. So I went through and read all the manuels I have and searched all over and couldn't find a definite answer.

Are these the kind that need torqued to specific spec. like 20~ft lbs ( I read in one manuel that Z code motors need torqued to 20~ft lbs, but that doesn't make sence either since our motors are Z code ) or is something else sound wrong?

I made sure to double check the motor is on the compression stroke and that the valves are closed, but something doesn't seem right. All the hardware is stock for right now.

Do you need longer push rods with vortec's?

TIA

 

[gjp]

Re: Vortec valve lash adjustment question?

ask mike. sounds like you had the reverse problem that I have.

 

[Black Knight]

Re: Vortec valve lash adjustment question?

I try not to bother him if it's something that I don't need a direct answer from him. Maybe if in a couple days I can't find the answer i'll call him.

In the manuel it says if you have srcew in studs like the ones you have pictured or the ones I have you tourqe to 20~ft lbs, but that is for pre-vortec heads so I want to make sure.

 

[jjorgensen52]

Re: Vortec valve lash adjustment question?

When I did my vortecs we used a set of 1.6 roller rockers, but we did use different pushrods. I forget exactly whether they were stock length, but my valvetrain is also 0-lashed (per Cranes specs for the rockers I have). We had no trouble going past 0 lash, so I would guess they are different.

According to what I just looked up, the Vortec motors actually have shorter pushrods... 7.187" v. the LB4's 7.192" ... the lifters are the same PN. Going by that, they certainly ought to work with the stock pushrods :dunno:

 

[MikeRenz]

Re: Vortec valve lash adjustment question?

you use stock length push rods w/ vortecs, as long as you use all standard valvetrain stuff anyway. What rocker studs are you using? The stock vortec rocker studs aren't the right size/shape for most self adjusting roller rockers. The stock stud don't have a thin enough perch to let the rocker seat completely down on the stud. That may be what you're running in to.

 

[jwaller]

Re: Vortec valve lash adjustment question?

do you have adjustable rocker studs or not? what is your pushrod, stud, and rocker combination?

 

[Black Knight]

Re: Vortec valve lash adjustment question?

Everything is stock in the valve train of the heads and i'm using the push rods that came with the LB4 motor. The lifters are also the original out of the motor. I basically just bolted these on my stock motor in hopes it would run better.

Are the rocker studs on a factory set of heads adjustable?

 

[ghettosled]

Re: Vortec valve lash adjustment question?

are you sure the rocker studs are 3/8-24 and not a metric thread?

 

[Black Knight]

Re: Vortec valve lash adjustment question?

Mike I know they're not 3/8-24, I tried to put a die on it and it was way too big. 8X1.25 started a little bit, but then bound up. I would venture to guess that they are 8X1.5, but have no way to comfirm that.

OK, so what does all this mean?

 

[jjorgensen52]

Re: Vortec valve lash adjustment question?

you need new rocker studs :lol: ? I have 3/8" studs on my heads

 

[Black Knight]

Re: Vortec valve lash adjustment question?

Well that sucks, I guess I get to spend more money.

I still don't understand why they don't work, I've read what Renz wrote earlier, but if they came off a running truck and nothing was changed, in theory why wouldn't they just bolt up and tighten down?

So do I have adjustable rocker studs or not?

 

[ghettosled]

Re: Vortec valve lash adjustment question?

Maybe you can get metric nuts instead of swapping the studs.. Most if not all the roller rockers come with either 3/8 or 7/16" fine thread nuts.. If your studs are metric you either need to replace them with the ARP studs (screw in vortec ones will be fine) or source some metric style polylocks, etc.

 

[gjp]

Re: Vortec valve lash adjustment question?

My studs did not work, Roy. I had to buy new ones. so exactly what are you looking for. I have these. If they work you can have them:

 

[SpoolingTurbo6]

Re: Vortec valve lash adjustment question?

Mike I know they're not 3/8-24, I tried to put a die on it and it was way too big. 8X1.25 OK, so what does all this mean?

It's a M8x1.0 Trust me!