I CANNOT get my valves adjusted. NSA Pro Mag 1/6, 14011051 GM Guideplates, Comp R lifters.

I've tried zero lash, rockers were jumping off the valve stems (SA rockers at the time). I've tried 1/16, no dice. 1/8 turn, no dice. I just got done setting them to 1/4 turn past zero lash, and they're still making a hellacious clacking and snapping sound!!!!

I'm doing each cylinder at TDC by firing order. I've tried feeling for zero lash by the moving the pushrod up/down method, by the spinning method, and I've even gone as far as calling zero lash when the pushrod starts to get hard to spin instead of just starting to feel drag.

On cylinder number three for some reason when I spin the retaining nut down it doesn't resist as much with the rest of the set, but the lifters are NOT collapsed.


I can't really do a dynamic setting because of my OVC wires, as I'd be needing replacements real quick!

How quiet is a NSA/Guideplated setup supposed to be??

Anyone got any ideas???? This is driving me NUTS!!!!!

 

I believe you'll have to check your pushrod length, is the rocker coming off on the inside of the valve or seem to be too long? check where the rr rides on the valve stem when the valve is fully open then check where the rr rides when the valve is fully closed , sounds like the roller may be rolling off of the valve stem

 

Hmmmm...........may be on to something there. The pushrods are stock length, 7.200" and the heads were milled somewhere in the area of .010-.014". However, given that the studs are now sitting on pushrod guideplates, everything should be about fine. I will say that I haven't seen any overstepping the valve stems when moving the motor by hand. When they were coming off with the SA rockers, they were jumping off the sides, if that's what you're referencing.

 

Just wanted to make sure you ck'ed pushrod lengths, probably something simple... don't overlook the simple things!

 

are you using the stock valve springs? Is it possible you are having trouble with coil bind?

 

It's a custom one off Joe Overton cam, so, no.

I'm using Combo EX 618 springs, set up for the cam.

 

I hate to say this but I personally haven't checked them. They were running fine on the previous motor, and the only change has been the bigger cam and the move to the NSA rockers and guideplates.

 

Sean,
I don't think that the guideplates will have anything to do with the pushrod length. Wouldn't the rocker just sit lower on the stud? The rocker height is determined by the spring and the pushrod, the stud is just there to hold it in place and let it "rock".

Rich

 

Did you check to see where the roller tip of the rocker rides the the valve stem when the valve is fully open and then fully closed?

 

Check to make sure that the bottom of your rockers are not hitting the hex of the studs. Some studs are taller in that regard. Adding guideplates brings the hex closer to the rocker.

 

What order exactly are you doing them in?

"Now it is time to adjust your rockers. You will need to be able to turn the crank (in the clockwise direction) to do these adjustments.

Turn the crankshaft until the cast arrow on the crankshaft hub is in the 12 o’ clock position and number 1 cylinder is at TDC. Watch number 1 cylinder valves as the crankshaft hub arrow approaches 12 o’ clock position.

If a rocker moves as the arrow moves to position, the engine is in the number 6 firing position. The crankshaft must then be turned one more time to reach cylinder number 1 firing position.

At this position, exhaust rockers 1, 3, 4, and 8 can be adjusted as can intake rockers 1, 2, 5, and 7. While spinning the pushrod with your fingertips, tighten the rocker down until you feel resistance in the pushrod - this is zero lash. Tighten the adjusting nut on the rocker arm an additional 1/2 - 1 turn (or whatever you think is right).

Turn the crank 360 degrees (clockwise) until the crankshaft hub is at 12 o’ clock again. Adjust exhaust rocker 2, 5, 6, and 7 and intake rockers 3, 4, 6, and 8 as you did in the step above. "

Taken from http://www.afrashteh.com/guide/install.htm

Just want to make sure we are on the same page on the order and the crank rotation, because, obviously that would play a big role in their correct adjustment.

 

This is not really the best way to adjust valves, as you may catch a lifter on a base cam lobe and screw up your zero lash point. Use this method as an approximation if you plan on doing the engine running method later. Fastbird is trying to do each cylinder(8 crank positions) one at a time which gets you much closer to zero lash then only using 2 crank positions.

Rich

 

TDC in firing order: 1-8-4-3-6-5-7-2

 

I had exactly the same trouble. I did the engine running method and it seems to be okay, and I have been driving it for about 10K now. I did 1/4 turn past "clack".

 

Hopefully that works for me too. I've got a good mind of what I need to do to keep the plug wires off the headers (OVC wires), so it's just a matter of actually going home and doing it today!!!