rocker arm adjustment
- Thread starter krazykyle
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On a hydraulic cam, it's set em' and forget em'. The lifter adjusts it's lash each time it goes from the base of the cam lobe to the ramp and an oil hole gets cut off and it cannot bleed down until next time around. They are self adjusting . On a solid lifter motor the adjustments are done mechanically and should be checked at least once a year, or after every race if you're into that.
a little bit out of adjustment--noise, less power, and possibly slightly more wear.
in the extreme, since it sometimes allows the rocker to keep loosening up, the arm comes off. i've never heard of this happening, it's just a theoretical possibility.
in the extreme, since it sometimes allows the rocker to keep loosening up, the arm comes off. i've never heard of this happening, it's just a theoretical possibility.
just pull ur valve covers and check em. i have had rocker arms come off while driving, racing. gives u an ugly backfire with a pretty nice flame. one time my rocker got so loose when i pulled the valve cover it had a couple chips from it missing. had to pull the whole motor out to find em. sometimes u will get a bent pushrod. ive made it a habit to check em every oil change.
the above is for loose, not tight.
tight causes noise, lack of power, excessive wear on the lifter, cam and valve spring. lose is definitely better than tight.
if it's a hydraulic cam adjustment is really easy. this assumes i remember everything correctly--i highly recommend getting the procedure from your cam/lifter manufacturer.
if the engine runs, warm it up, then pull the valve covers.
rotate the engine till the both both valves on the cylinder are closed--usually 20-90 ?degrees after the intake closes.
then loosen the nut and retighten while spinning the pushrod. once you feel resistance AT ALL stop. tighten another 1/4-1/2 turn, this depends on the cam manufacturer.
tight causes noise, lack of power, excessive wear on the lifter, cam and valve spring. lose is definitely better than tight.
if it's a hydraulic cam adjustment is really easy. this assumes i remember everything correctly--i highly recommend getting the procedure from your cam/lifter manufacturer.
if the engine runs, warm it up, then pull the valve covers.
rotate the engine till the both both valves on the cylinder are closed--usually 20-90 ?degrees after the intake closes.
then loosen the nut and retighten while spinning the pushrod. once you feel resistance AT ALL stop. tighten another 1/4-1/2 turn, this depends on the cam manufacturer.
I used to run poly-locks on my 68' Firebird 400. Even though it was a hydraulic cam, when ever I adjusted them the motor just ran so much smoother and stronger. What I did was pull the valve covers and run the motor at idle. Then loosen each poly-lock until the rocker clacked, then tighten it down until the clacking stopped. That is 0 lash. Then I gave it a 1/4 turn more and locked it down. Do this to each rocker and then burn your oil drenched clothes. No matter what I used, clips, cut open valve covers, it made a huge mess, but the results were worth it. Of course the average Joe would probably not notice the difference, but I did.
watch this video: http://www.youtube.com/watch?v=BgIzn2neiuY
the video is very well done and very clear. It will teach you how to adjust your valve lash, for both hydraulic and solid cams.
I could go into further detail on how to set your lash, but first you need to find out what kind of cam you have. To do this, you can...
the way I DON'T recommend:
pull off your valve cover, undo the rocker arm, and pull out the pushrod. Then, WITH A FLASH LIGHT, take a magnet and fish into the cam valley and pull out the lifter. It should look like one of these:
hydraulic lifter: notice the little oiling hole
solid lifter: looks pretty much the same, except the pushrod seat is solid, you will not see any clips or moving parts, it is simply a concave bowl
you may have roller lifters, in which case it will look like either of those lifters with a little wheel on it.
the way I recommend:
adjust the lash as it is, and wait and see if it loosens up again after a year.
Chances are, you have a normal hydraulic cam. Solid cams went almost extinct back in the 70s and are now only used for race or heavy street applications. My engine has a solid cam, and since I did not build it, I did not know this until I blew some lifters and pushrods at the strip because they were loose.
the video is very well done and very clear. It will teach you how to adjust your valve lash, for both hydraulic and solid cams.
I could go into further detail on how to set your lash, but first you need to find out what kind of cam you have. To do this, you can...
the way I DON'T recommend:
pull off your valve cover, undo the rocker arm, and pull out the pushrod. Then, WITH A FLASH LIGHT, take a magnet and fish into the cam valley and pull out the lifter. It should look like one of these:
hydraulic lifter: notice the little oiling hole
solid lifter: looks pretty much the same, except the pushrod seat is solid, you will not see any clips or moving parts, it is simply a concave bowl
you may have roller lifters, in which case it will look like either of those lifters with a little wheel on it.
the way I recommend:
adjust the lash as it is, and wait and see if it loosens up again after a year.
Chances are, you have a normal hydraulic cam. Solid cams went almost extinct back in the 70s and are now only used for race or heavy street applications. My engine has a solid cam, and since I did not build it, I did not know this until I blew some lifters and pushrods at the strip because they were loose.
I have hydraulic lifters but I'm not getting any oil up through the push rods on the passenger side. What could be the problem here?
I'm really not sure...veltboy314 said:
how did you check that there's no oil coming thru? It's very hard to tell. One good way to see is to watch the hole in the rocker above the rod... little bits of oil should be bubbling out of it when the engine is running. Make sure the engine gets up to temperature when you check.
One problem could be that something is clogged in the pushrod. Take the push rods out, make sure you keep them in the same order and position you took them out. Clean them off with some brake clean, and blow down the hole with compressed air. Then, to make sure oil is flowing thru, dip it in oil and pick it up to see if oil flows out the other end.
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