QuicheLorraine

I've been driving the 76 for four days or so since it came off the dyno. It runs great & I'm pleased with the work I did to it.

The only thing I'm concerned about is valve noise. I used the same Crane 1.6 roller rockers that I had on the old heads. Before, I had very little valve clatter but now it's too much in my opine.

I just re adjusted the valves on the aluminum heads - and got the same results - too much noise.

My method of adjustment was 1/2 turn past zero lash on the hydraulic (flat tappet) lifters. I did each cylinder rotating in turn, just after the intake valve closed.

I'm wondering if I go in and give 'em another 1/4 of a turn, if that will help with the valve clatter. I have always used 1/2 turn before and I've done a lot of engines.

For some reason though, these valves are clattering too much for me, at 1500-2000 RPM.

The AFR heads made a wonderful improvement on the motor and it even runs a good 10* cooler than before. Oil pressure is great and it runs terrific.

Why the valve noise?

TimAT

Lots of differing opinions, but I'd adjust them with it running. Back off until the rattle, tighten until they just quit, then another 1/4 turn. It's messy, but it's worked for me since 1967.

midyearvette

you can go deeper if you like.....the standard adjustment for early vettes was 1&1/2 turns......you could turn them down some more and not even run the mill.....just give it ample time for the lifters to bleed down before start up......the deeper you go usually floats the valves at a lower rpm ,.....

QuicheLorraine

I've also done that many times with OEM rockers. Seems it would be harder to do with current setup.

c31980

what i know about roller rocker ,,that they make mutch noise than the stock one due to
thier bearing ,,if u use the stock one do u have the same issue ??

midyearvette

nope, same set up just have to back off the poly lock.......

QuicheLorraine

I don't have OEM rockers to try so I can't answer your question well.

QuicheLorraine

It will certainly make a mess out of the headers but it may be worth trying. Maybe I can get my hands on a valve cover I can chop up. I have clips to fit OEM rockers for adjusting 'em but they won't work with the Crane roller rockers.

70BBvert

Take an old valve cover an cut the center of the top off. Install it with a gasket & it'll keep the oil contained. Most of it anyway especially if you refrain from excessive revs. Make sure the engine is warmed up before you swap valve covers.

Jim

jackson

Rollers rockers are typically noisier.
Before you adjust lifters, Check & Ensure:
All springs (inner/outer/damper) are intact & Not broken.
All guideplates are adjusted correctly & Cannot shift.
All RA are aligned correctly.
BODY of RA is Not contacting retainer.
BODY of RA is Not contacting valve tip.
No part of any RA is contacting valvecover.

larrywalk

With a hydraulic cam, readjust your valves with a cold engine with the piston at TDC firing, not at when the intake closes. Reason is that TDC firing puts both the intake and exhaust valves definitely on the base circle. With positioning at intake valve closing, the lifter may not have been completely off the closing ramp.

I prefer 3/4 turn after zero lash to center the plunger in the center of the hydraulic lifter. With the standard 3/8-24 rocker studs, one turn of the nut lowers (or raises) the rocker arm pivot by .042 inch. With a standard rocker ratio of 1.5, the pushrod end will change by .069 inch; half a turn down from zero lash preloads the lifters plunger by .035; 3/4 of a turn preloads the hydraulic lifter by .052 inch.

pauldana

don't know if this will help or not, but I installed roller cam and rockers on my last build, and I have had a different type of sound ever since... scared me at first... kind of sounded more like a sewing machine.. I thought the lifters were not adjusted correctly, so I took it to a local speed shop and had the to "recheck" and or readjust the lifters... same sound.... nothing like the flat tappet lifters I had... runs great... guess the sound is normal..

63mako

I would follow these to a tee. Different lifters require different preload. A comp high energy requires 1/2 to 3/4 turn preload. A Comp Pro Magnum requires zero to 1/8 turn preload. This is the correct method and adjustment preload for your lifters. This is the only way I would set them. That is just me.
http://www.cranecams.com/?show=techarticle&id=2
Crane recomends 1/2 to 1 full turn past zero.

Hydraulic Lifters Can Be Adjusted at Any Engine Temperature Since hydraulic lifters can compensate for thermal expansion of the engine, the adjusting can be done with the engine cold; hot adjustment is not necessary.



Adjusting Hydraulic Lifters for Proper Preload

In order to adjust the preload, the lifter must be properly located on the base circle or "Heel" of the lobe.

At this position the valve is closed and there is no lift taking place. You will need to watch the movement of the valves to determine which lifter is properly positioned for adjusting.

1. Remove the valve covers, and pick a cylinder that you are going to set the preload on.

2. Hand rotate the engine in its normal direction of rotation and watch the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop and adjust that cylinder's intake rocker arm. (Why? Because when the exhaust valve is just beginning to open, the intake lifter will be on the base circle of the lobe, the correct position for adjusting the intake.)

3. Back off the intake rocker arm adjuster and remove any tension from the pushrod. Wait a minute or two for that hydraulic lifter to return to a neutral position. The spring inside the lifter will move the pushrod seat up against the retaining lock if you give it time to do so. (If you are installing brand new lifters they will be in the neutral position when they come in the box.)

4. Now spin the intake pushrod with your fingers while tightening down the rocker arm. When you feel a slight resistance to the turning of the pushrod, you are at "Zero Lash". Turn the adjusting nut down one half to one full turn from that point. Lock the adjuster into position. The intake is now adjusted properly.

5. Continue to hand turn the engine, watching that same intake. It will go to full open and then begin to close. When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. (Again, when we see the intake almost closed, we are sure that exhaust lifter is on the base circle of the lobe.) Loosen the exhaust rocker arm and follow the same procedure described before in steps 3 and 4 to adjust this rocker arm.

6. Both valves on this cylinder are now adjusted, and you can move on to your next cylinder and follow the same procedure again.

OldCorvetteKid

I've used a cut up cardboard box and duct tape to get a valve cover shape to contain the oil splash when adjusting while running...its still a little messy tho...

hwcoop

Didn't spill a drop when I did this and it gave me an excuse to buff up my aluminum covers.
When I put my motor together I only used about 1/2 turn but found I was getting valve train noise so I adjusted them to 1 turn per GM manual and no noise since.

Ironcross

ICE, intake closes adjust the exhaust..thats good for the exhaust valve, but how did you adjust the intake?

EOI maybe?

midyearvette

one more time......adjust the intake when the exhaust STARTS to open.....adjust the exhaust when the intake is fully open and STARTS to close.....very important.also valve location is EIIEEIIE.....

MotorHead

Cutout a slot in the top of an old valve cover. Start the motor and back of the nut till it ticks then tighten until no tick then another 1/2 turn and your done.

scottred80

I had , rocker noise , with my build too ,, check the inside of your valve cover , my roller rocker was just cliping the valve cover ....opened the mounting holes ,on valve cover solved the problem ..

Les

Have you checked for clearance between the rocker arms and valve covers? I'm wondering if a small difference in the mounting height of the rockers on the new heads relative to the rail height for mounting the valve covers hasn't put the rockers in contact with the valve covers.

Well, I just saw the post above mine- I scanned quickly but missed that one. It looks like we're trying to say the same thing in a slightly different way.