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Topic: setting up new rockers

in Forum: C3 Engines


setting up new rockers

Posted: 5/3/05 10:29am Message 1 of 4
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SHOHOLA, PA - USA
Joined: 8/31/2004
Posts: 67
Vette(s): 1978 Dark Brown coupe auto 1977 White coupe auto 1974 Dark Green coupe man 1969 Yellow coupe man 1994 blue coupe 6spd

Hi all,

Just installed a voodo cam, new 64cc heads, and steel roller rockers

I wanted to know whats the best way to adj the rockers for the first start up and then the adj when running.

thanks

pete kennedy

1978 auto




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setting up new rockers

Posted: 5/3/05 10:33am Message 2 of 4
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Hot Springs, AR - USA
Joined: 4/24/2004
Posts: 3236
Vette(s): 69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans

take a look around in the c3 engines forum..

I know ive posted very detailed instructions quite a few times..  with good feedback on the results..

ken has also posted his method a few times...

quite a few other members have elaborated and added their own methods in these threads as well




setting up new rockers

Posted: 5/3/05 11:57am Message 3 of 4
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Batavia, IL - USA
Joined: 3/27/2003
Posts: 622
Vette(s): 496 big block, Dragvette 6 link, 12 bolt IRS conversion, Going for fastest Vette IRS E/T
Here is an old thread that might be helpful, Same method applies to small block engines. Rocker adjustment

I perfer the Dynamic method, much faster and alot less guess work. Its just messy that all.Tumarr38475.4993981481


setting up new rockers

Posted: 5/3/05 12:39pm Message 4 of 4
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Portland, TN - USA
Joined: 4/29/2003
Posts: 805
Vette(s): 1972 Coupe Anything, but Stock and more mods to come! SSBC Force 10 Brakes, 3.73, TH350, 355 CID, Rack and Pinion, Vette Brakes suspension front and rear.

I'm not so sure your worried about setting up your rocker arms as much as you are about setting your preload on the lifters which requires adjusting the rocker arms.

Most cam sights have this info, but here is a cut and past from Cranes website and its real easy to follow, just make sure you follow the directions following the firing order for your engine.

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 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.

Do Hydraulic Lifters Need to be Primed with Oil?
Many people mistakenly believe that hydraulic lifters must be soaked in oil overnight and be hand pumped up with a pushrod before installing into a new engine, however this is not necessary. In fact, this could cause the lifter to act as a “solid” and prevent obtaining proper preload. What is very necessary is the priming of the entire engine’s oil system before starting up a new engine for the first time. This is done by turning the oil pump with a drill motor to force oil throughout the entire engine. Crane Cams offers oil pump primers for Chevrolet and Ford engines.

What is a “Fast Bleed” Hydraulic Lifter?
Part of engineering a hydraulic lifter is to determine what its “Bleed Rate” will be. The “Bleed Rate” is a scientific method of determining the time it takes the hydraulic lifter to lose its pressure once it is fully pumped up solid with oil. By changing this rate, the lifter can give different performance factors to the engine. One such design is the Crane Cams Fast Bleed Lifter. Its increased bleed rate enables it to provide improved vacuum, increased cylinder pressure and performance in the lower RPM ranges. It is best suited for those engines that are using a big camshaft profile that requires more compression ratio than the engine actually has. This situation would normally cause a loss of “bottom end” performance, but with the Crane Cams Fast Bleed Lifter the bottom end torque is restored.

NOTE: Fast Bleed Lifters are only for use if the compression ratio is below the recommended minimum shown on the application page for the particular camshaft you have
selected.


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in Forum: C3 Engines


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