Cascade Crew

[townaj]

Ok so I'm trying to set my damn lash. I have hydraulic flat tappet lifters and today I bought full roller rocker arms. But I have seen two definitions on what zero lash is. 1)Tighten until there is SLIGHT resistance on the pushrod when you spin it plus 1/4 turn, or 2) tighten until the pushrod doesn't spin at all. I am thinking that the second one is right. I have adjusted my lash the first way, but with 3/4 turn, a couple times now, but they still were clattering. Help me PLEASE I'm sick of not being able to drive/race this thing. Thanks

[aaron_sK]

They way I was taught to do it (and this may be wrong) is to move the pushrod up and down as you tighten the nut. When it stops moving, go one quarter turn.

[Dewey316]

Firzt one is right. If the pushrod isn't spinning you are too tight. Zero lash is when you feel resistance on the pushrod, but can still spin it by hand fairly easily.

From there, 1/4 turn and be done.

[townaj]

Ok thats what I thought. I still have a LOT of noise from the rockers though...think the lifters could be shot? I'm at a loss...

[MrMike98]

r u doing this with the engine running or not?
if not make sure ur at TDC on each cyl prior to setting lash

[townaj]

Nope I'm doing it with the motor off. I tried with it running. Once. Never again. I've been setting the exhaust valve when the intake is almost closed and setting the intake valve when the exhaust just opens. Everyone I've talked to told me to set it like that. But they still chatter.

[MrMike98]

do it the recommended way. the firing order 18436572,

adjust #1 when at TDC when rocker arms for #6 just rock between each other.
then #8 when at TDC when rocker arms for # 5 etc

then # 4 at TDC with 7 rocking

then 3 when 2 rocks

then 6-1
5-8
7-4
2-3
i hope u understand, just make sure (by what ever method u like)that u are at TDC when setting lash.

[chevymad]

TDC method will probably work for him since I doubt he has a very big cam. But... and actual cam designers will tell you this, tdc is not the bottom of the base circle. The method he was trying ICEO is the correct method for anything much bigger then stock. There's a cam designer that posts on team chevelle, goes by UD Harold. He designed some of the early comp cams, owned Ultradyne until they went under, designed the lunati voodoo line, and is back at lunati now. He recommends this method and is where I came across it. Funny though.. whenever I go to adjust one, I can never remember if its intake opening or closing.. have to think about how a cam works to figure it out again.

[townaj]

Yeah I was using the EOIC method. For me its easier to remember the letters in that order, idk why. So heres what happened yesterday, I put my new roller rockers on, adjusted lash, then started it. It sounded alright (no chatter) so I took it for a test drive around the block. Got back to the house and listened again, and there they were just chattering away. I don't have a huge cam, its only about .480 lift. So are they coming loose? They shouldn't cus I have the poly locks on there...what the hell is going on. I need to get this solved by monday, I'm taking it to get it tuned.

[chevymad]

Is it quiet again when cold? Is it more then one making noise?

0.480 lift really tells us nothing about the size of the cam. It could be 330 duration or something which would make it huge. Lift is only one aspect, and its not the one that really changes the performance of the engine all that much. Duration and overlap are what will determine how a cam sounds and what rpm range a motor will run in.

Some cams will make noise. They make more noise when they're hot because the oil is thinner. The cam in my truck drives me nuts. Some rpm ranges it sounds terrible. But lash is fine and it has run several years that way.

If you only have one lifter making noise again, you could have a bad lifter, or a cam going flat. Another possiblitiy is you could be pulling the rocker studs out if they're not screw in type.

[townaj]

Nope it makes noise cold too. Its just one type of noise but its coming from almost every rocker it sounds like.

Duration isn't that high. I believe its only about 240.

Its definitely coming from more than one place. I bet I didn't set the poly locks right and they came loose. I don't have screw in studs, but the springs are not all that stiff. The pressure is about the same as stock so I wouldn't think they would be pulling out. And they don't seem to be. All the measurements are the same, but its possible.

[izcain]

Chevrolet has always recommended between 3/4 and 1 turn from zero lash depending on what manual you look at 1/2 turn is fine. We always had big go around at the Chevrolet dealer I worked at about this. A hydraulic lifter has .100 distance between top to fully bottomed out on the plunger. 1/2 turn on the threads makes the distance .050 which centers the plunger in the lifter bore. This is all with the studs being ok not pulling thru at all.

One thing to be aware of is that Rollers are going to be substantially more noisey then standard rocker arms.

Did you check how the installed height was on the rockers to see if they are centered on the valves.... sometimes you may need to change pushrods to get them to center up. Just some ideas.

[townaj]

Ok so its normal for them to be a little noisier. Thats good news.

I actually did check for that and they are pretty damn close. But longer pushrods wouldn't hurt anything. I think all is ok now. Theres no one valve that stands out as being noisier so I'm assuming its just normal valve train noise. It drove into town today fine also. Just a little under powered from a couple carb adjustments. Soon as I pick it up from getting tuned I'll let you guys know what the deal is. Should be fun

[Twilightoptics]

Don't buy longer pushrods if you haven't used the sharpie check yet. Length is based on where the roller/rocker rides on the valve stem.

[izcain]

[townaj]

Yeah I kinda wish I could get an O2 sensor to help with tuning. But all that stuff is expensive. I need to find a job lol.