Engine Rocker Arm Adjustment

RangerJoe · Nov 13, 2014

When I b put the engine together, i put the lifters on the base of the cam, hand tightened the pollock until I felt drag on the pushrod, then turned the poly lock 1/2 turn and locked the set screw.

I drove the car for the first time today, and the rockers were pretty noisey, which I know is pretty normal with an aggressive cam. I decided to recheck all my adjustments today and pulled the covers.

I am doing the adjustments with the cam on the base lobe, but every time I go to put in my 1/2 turn, it looks like the valve is pushing open. Is this normal?

Joe

Dave2000GT · Nov 13, 2014

No if the valve moves at all something isn't right. Are you sure you're on the base lobe, not off by 180 ? Having the timing marker at 0 deg doesn't mean you're at TDC on cylinder 1, it only hits TDC every second rotation. If you're not on base lobe then it'll cause you to not preload the lifters causing the noise. There's a few techniques to makes sure your on base for each particular valve. Myself I just find TDC, adjust the valves closed, then go to then next 2 positions for the rest of the valves as defined in the Haynes manual.

RangerJoe · Nov 14, 2014

Well, after reading in an LS forum.....I adjusted the rockers, letting them push the valves open a small amount. I went through the rest of the rockers and came back to the ones I started with. Just like the LS forum stated, the rockers bled down and the valves were closed again.

Joe

Dave2000GT · Nov 14, 2014

RangerJoe said:
Well, after reading in an LS forum.....I adjusted the rockers, letting them push the valves open a small amount. I went through the rest of the rockers and came back to the ones I started with. Just like the LS forum stated, the rockers bled down and the valves were closed again.

Joe

Yeah actually that makes sense, just movement after zero lash during preloading of the lifters. Any change after re-doing them?

Micheal Nadeau · Nov 14, 2014

You don't adjust all the lifters at one time. It's #1 at TDC adjust certain valves, rotate 360 degrees and adjust certain valves, then rotate 90 degrees and adjust remaining valves. Everything I have ever seen with a valve adjustment was tighten until pushrod has drag on it and turn lock nut 90 degrees. LS chevy motors don't set up like a ford Windsor motor.
5.0L HO
No. 1 Cyl. at TDC Nos. 1, 4, 8 Intake Nos. 1, 3, 7 Exhaust
Rotate 360° Nos. 3, 7 Intake Nos. 2, 6 Exhaust
Rotate 90° Nos. 2, 5, 6 Intake Nos. 4, 5, 8 Exhaust

Dave2000GT said:
No if the valve moves at all something isn't right. Are you sure you're on the base lobe, not off by 180 ? Having the timing marker at 0 deg doesn't mean you're at TDC on cylinder 1, it only hits TDC every second rotation. If you're not on base lobe then it'll cause you to not preload the lifters causing the noise. There's a few techniques to makes sure your on base for each particular valve. Myself I just find TDC, adjust the valves closed, then go to then next 2 positions for the rest of the valves as defined in the Haynes manual.

Every time that mark says TDC, cylinder 1 is at TDC, its whether its on a compression or exhaust stroke that is different.

Dave2000GT · Nov 15, 2014

Micheal Nadeau said:
You don't adjust all the lifters at one time. It's #1 at TDC adjust certain valves, rotate 360 degrees and adjust certain valves, then rotate 90 degrees and adjust remaining valves. Everything I have ever seen with a valve adjustment was tighten until pushrod has drag on it and turn lock nut 90 degrees. LS chevy motors don't set up like a ford Windsor motor.
5.0L HO
No. 1 Cyl. at TDC Nos. 1, 4, 8 Intake Nos. 1, 3, 7 Exhaust
Rotate 360° Nos. 3, 7 Intake Nos. 2, 6 Exhaust
Rotate 90° Nos. 2, 5, 6 Intake Nos. 4, 5, 8 Exhaust

Every time that mark says TDC, cylinder 1 is at TDC, its whether its on a compression or exhaust stroke that is different.

Yup that is true - idea is you need to be on TDC compression at the start of the sequence, but regardless looks like the OP didn't do anything wrong, they just noticed the slight valve movement during lifter preload. I haven't actually noticed it before, I've only noticed the valves move when I messed something up and wasn't on base circle for the valve.

RangerJoe · Nov 15, 2014

Dave2000GT said:
Yeah actually that makes sense, just movement after zero lash during preloading of the lifters. Any change after re-doing them?

They seem to be quiter. Took it out for a ride and romped on it a little more. Definetly more powe over the GT40's.

Micheal Nadeau said:
You don't adjust all the lifters at one time. It's #1 at TDC adjust certain valves, rotate 360 degrees and adjust certain valves, then rotate 90 degrees and adjust remaining valves. Everything I have ever seen with a valve adjustment was tighten until pushrod has drag on it and turn lock nut 90 degrees. LS chevy motors don't set up like a ford Windsor motor.
5.0L HO
No. 1 Cyl. at TDC Nos. 1, 4, 8 Intake Nos. 1, 3, 7 Exhaust
Rotate 360° Nos. 3, 7 Intake Nos. 2, 6 Exhaust
Rotate 90° Nos. 2, 5, 6 Intake Nos. 4, 5, 8 Exhaust

Every time that mark says TDC, cylinder 1 is at TDC, its whether its on a compression or exhaust stroke that is different.

Never said I did. I started with piston 1 at TDC and rorotated the engine as needed following Ed Curtis' valve adjustment guide. Was just concerned that the valves were opening slightly, but it all worked out.

Thanks for the replies guys. Always good to hear a different perspective.

Joe

Dave2000GT · Nov 15, 2014

RangerJoe said:
They seem to be quiter. Took it out for a ride and romped on it a little more. Definetly more powe over the GT40's.

Joe

I'm guessing these are the 'coming soon' AFR185s ? How does the bottom/mid-range compare, improvement there too ?

RangerJoe · Nov 15, 2014

Dave2000GT said:
I'm guessing these are the 'coming soon' AFR185s ? How does the bottom/mid-range compare, improvement there too ?

Yep, they are the 185's, FTI cam and systemax intake. I can't say for sure as of yet, I really haven't put more than about ten miles on it and I have my regular radials on it at the moment.

I will say this, it has a hard time idling cold, and my power brakes come and go. It appears the cam does not make very much vacuum. I am a little disappointed in that, seeing how I told Ed this was a street/strip car with AC, PS and PB. I think I can remedy both situations, the first with a tune and the second with a vacuum canister.

I really don't think this new combo will make less power anywhere, at least not noticably.

Joe

Engine Rocker Arm Adjustment

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