Hello guys... I need some help with my car. Yesterday I installed some 1.6 ratio Crane gold Rockers on my car.. I took off the 1.5 which were working fine and installed the 1.6 ratio rockers. I installed the rockers and the first time i set the preload to half a turn. In other words I did a 180 degree turn to set the preload after there was no valve lash. The car started up fine without any problems until i was about to take it out for a drive.. As i was pulling out... it started booging a little, making noise and shaking.. I went back, took off the valve covers and everything seemed fine... So i figured since the car wasnt working that great, the engine is missing compression, meaning the valve wasnt closing right which is cause by the rocker arms being too tight.. I went on youtube, and saw a video of rocker arm installation.. http://www.youtube.com/watch?v=BgIzn2neiuY in the video he only does 1/4 of a turn.. So i went ahead and did that, and at first the car seemed better but now it is bad performance wise.. It shakes and doesnt accelerate without making valve noise... Could it be that I need to tighten the rockers more? Is there something that I may be missing?? If anyone has installed them before(which im sure of) how did you all do it??

Any help would be great guys.. Thank you.

 

Tell everyone what your engine mods are. There is nothing known about your car.

 

Well, It has a 268XFI cam with beehive springs.. Other then that... just a few bolt ons... Headers, tune, etc. Nothing major

 

Use this method, read 7 & 8. Thats how I do mine and never had an issue. I do how ever only go1/4 past zero lash, but 1/2 should also be ok. This is assuming you have an average set up.
http://www.compcams.com/v002/Instructions/Files/151.pdf

 

Did you make sure the cam was on the base circle? From the way you worded all that it sounds like you installed them and tightened them all down at the same time...

 

Yup, made sure they were all on the base circle.. I followed the sequence in the haynes book... With the number 1 piston at TDC and then turning it another whole turn and adjusting the ones that are left..

 

Yep, I know the core cause; Haynes manual procedure.

Join the club of some many others who've had the same problem. What you're going throught is the MAIN reason I always make a DIRECT point NOT to use it. Too error prone; too easy to make a mistake.

You'd be ABSOLUTELY amazed at how often this happens to guys using that procedure. I'm regularly visit 8 or so different Forums and this comes up all the time. The 8 sites I visit are only a drop in the bucket of the total number of other Forums where other guys are probably having the same issues.

Best advice: Save your sanity, use the Intake Closing/Exhaust Opening (IC/EO) method to find zero lash.

I created a longer, more detailed version, but here's a CompCams' shortened version of how to do it. They wouldn't recommend it if there was a better way.

Section I. Setting preload with ADJUSTABLE ROCKER ARMS

Turn the engine in the normal direction of rotation. Start with cylinder number one (1).

When the exhaust valve begins to move, adjust the intake valve to the correct preload. To reach zero, take the pushrod between your finger tips and move it up and down while you tighten the rocker arm.

Once you feel the pushrod has no more vertical slack, you are at zero preload. Make sure the pushrod is in the lifter and the rocker arm seat when making valve adjustments.

As stated before the best setting is .030” to .040”, or ½ to ¾ a turn of the wrench past zero. Now, you can move on to the exhaust valve on the same cylinder. Begin by rotating the engine over again until the intake valve
reaches maximum lift and is almost all the way back down.

Then set the exhaust valve using the same method as the intake (.030” to .040”, or ½ to ¾ a turn of the wrench past zero).

Continue adjusting the valves on each cylinder in this manner until all valves are adjusted.

If you'll notice, there's nothing about finding TDC, etc. You just watch the valve train.

Jake

West Point ROCKS!

 

I did the procedure noted with the pro magnums instructions, and it worked flawless.

 

I'm sure the Haynes manual has the 1 and 6 TDC procedure that has been in effect since time began on SBCs (same method is in the GM factory service manual). It works perfectly as long as you have 1 and 6 TDC identified by pulley/crank position (I've used it for 40 years without an issue). If you have highly aggressive cam lobes or don't know if the hub is indexed correctly the method for watching the valve train events may be better advised. These two methods and another are listed on my Tech Page.