ji i ahve a couple of stangs here in halifax canada and i am a submariner in the canadian forces, i have bought a set of 1.7 `rane cobra rockers , can i just bolt these in and tighten until the bolts stop turning lol, because i sometimes get the feeling that the car now has more power when cold and when it heats up, its like i lose the additional lift any input on how these are supposed to be installed would be great thanks brian.
are pedestal rockers truley bolt down?
- Thread starter Brian85cobra
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cenok is family
15 Year Member
no you can't just crank down on them. here' how you do it, taken from crane's site:
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 cylinders 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". From there, you need a torque wrench set to 18-20 ft/lbs. turn the torque wrench until you reach 18-20, you should be able to do it in 3/4 to 1 full rotation. if it takes more than that, you need to shim it.
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.
**EDIT** i noticed these instructions were for stud mount, so the part in bold is a change i made. the rest is the same.
here's crane's actually install instructions: www.cranecams.com/pdf/22e.pdf
when i got my afrs in i was going to recheck all that zero lash stuff but i did not. i used all my old shim stuff on my afrs. it worked fine.
then i called afr and double checked to see if they are TRULY stock bolt on replacement, they said yes. i called a couple of times to get different opinions, they were all the same. sooo , i just bolted them down with out any shims just like the stock heads and now im running 9psi about 10months later, no problems. knock on wood.
then i called afr and double checked to see if they are TRULY stock bolt on replacement, they said yes. i called a couple of times to get different opinions, they were all the same. sooo , i just bolted them down with out any shims just like the stock heads and now im running 9psi about 10months later, no problems. knock on wood.
cenok is family
15 Year Member
well in a way they are. you torque down the factory stamped arms to 18ft/lbs as well. setting the lash is going to be better for your valvetrain in the long run though. valve timing being off can rob you of a little bit of power too. also, roller rockers have a tendency of being noisy, so it'll help with that if you get them down correctly.
Maryland Stang
Active Member
You won't get the most power by just torqueing them in but they are designed for just that. On a stock Ford base circle roller cam you can just install them and go. When Ford installed them on the Cobra engine they just bolted them in the way they were and didn't bother shimming them to perfection.
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