I know this is an old and tired question that has been ask a thousand times... but I have read many many articles, watched too many YouTube videos about adjusting steel push rods from zero lash to 004... I know the engine needs to be cold and the rotor needs to be pointed to the valve that's about to be adjusted. What is the correct setting for adjusting these push rods. Are the settings from different forums offered by so and so their own personal preference?
Replies sorted oldest to newest
People call it loose zero- there's no play but you can easily spin the pushrod between 2 fingers. Some say .001" clearance is ok too. When checking with a magnet to see what pushrods you have it's the middle piece (not the ends) you're putting the magnet to.
Any figure of .004-.006" is for aluminum bodied pushrods- this is to allow for the expansion/growth of the aluminum section as the engine warms up. Note that on these pushrods the ends will be steel as well
ALB's info is correct, as expected. :-)
The only thing I'll add is that Pat (Downs) changed his adjustment spec from "zero" to 0.002" back when he was at CB. I honestly think I recall him saying he did that because he was tired of arguing with shops about a "loose zero" and the range of zero to 0.002" was acceptable, but I don't want to put words in his mouth. His current Pat Downs Performance (PDP) paperwork lists valve adjustment clearance as 0.003" exhaust and intake. And of course this is all for non-stock steel/chromoly push rods. I'll have to ask him about the change when I speak with him later this week.
To complicate this even further, we received an engine from a different builder recently that had implicit instruction NOT to adjust in the normal TDC/BDC, rotor pointed at the wire manor. In their instructions they have you watch the rocker arm and stop when it is at full lift, then move to the opposite side and adjust that one, knowing it is on the heel of the cam lobe. My only educated guess is that there is a ton of overlap on these particular cams and the lifter is still on a ramp at TDC/BDC. Obviously not a common thing since its the first time I've run into it EVER, but one more possibility to throw a wrench into things.
@chines1 posted:ALB's info is correct, as expected. :-)
The only thing I'll add is that Pat (Downs) changed his adjustment spec from "zero" to 0.002" back when he was at CB. I honestly think I recall him saying he did that because he was tired of arguing with shops about a "loose zero" and the range of zero to 0.002" was acceptable, but I don't want to put words in his mouth. His current Pat Downs Performance (PDP) paperwork lists valve adjustment clearance as 0.003" exhaust and intake. And of course this is all for non-stock steel/chromoly push rods. I'll have to ask him about the change when I speak with him later this week.
To complicate this even further, we received an engine from a different builder recently that had implicit instruction NOT to adjust in the normal TDC/BDC, rotor pointed at the wire manor. In their instructions they have you watch the rocker arm and stop when it is at full lift, then move to the opposite side and adjust that one, knowing it is on the heel of the cam lobe. My only educated guess is that there is a ton of overlap on these particular cams and the lifter is still on a ramp at TDC/BDC. Obviously not a common thing since its the first time I've run into it EVER, but one more possibility to throw a wrench into things.
Can't thank you enough for this information! Prior to setting the valves to .002 the car idled ruff around 600 and small vibrations... The car has 2110 engine with an Engle 110 cam so I set all the valves to .002 and the idle is back to 1k and running very smooth. Thoughts?
I adjust my valves the last way you mentioned. But I do it because I don't have a distributor, and as you know it's hard to see the crank pulley in a Spyder.
Instead of thinking or trying to remember what I've done, I use a white board and a dry erase marker to keep track of which valves I adjusted. Easy peasy.
@Todd Dean posted:Can't thank you enough for this information! Prior to setting the valves to .002 the car idled ruff around 600 and small vibrations... The car has 2110 engine with an Engle 110 cam so I set all the valves to .002 and the idle is back to 1k and running very smooth. Thoughts?
Did you check your valve clearance before resetting them?
@DannyP posted:I adjust my valves the last way you mentioned. But I do it because I don't have a distributor, and as you know it's hard to see the crank pulley in a Spyder.
Instead of thinking or trying to remember what I've done, I use a white board and a dry erase marker to keep track of which valves I adjusted. Easy peasy.
I had a degree wheel on mine. After the first time, I broke out some paint pens and marked TDC and BDC in white, and 15° and 30° timing marks in orange on the edge of the pulley where I could see it. But watching the opposite valve is just as easy.
@LI-Rick posted:Did you check your valve clearance before resetting them?
Yes, some were 004. and others were zero... I did have an issue with number 3. There were 2 scrapes inside the valve cover before any adjustments. What do you think about it?
Anyone else including LI-Rick that knows what this is and explains how to fix it would be much appreciated
@dlearl476 posted:I had a degree wheel on mine. After the first time, I broke out some paint pens and marked TDC and BDC in white, and 15° and 30° timing marks in orange on the edge of the pulley where I could see it. But watching the opposite valve is just as easy.
I have a degree wheel as well. And I filed marks at TDC and BDC and at 32 degrees. But not having a distributor is problematic. It is easier to just pull both covers and do the valve OPPOSITE the fully open one.
Todd, with stock valve covers and bigger cams/ratio rocker arms, sometimes valve covers need to be gently massaged with a ball-peen hammer and a lead shot bag.
@DannyP posted:I have a degree wheel as well. And I filed marks at TDC and BDC and at 32 degrees. But not having a distributor is problematic. It is easier to just pull both covers and do the valve OPPOSITE the fully open one.
Todd, with stock valve covers and bigger cams/ratio rocker arms, sometimes valve covers need to be gently massaged with a ball-peen hammer and a lead shot bag.
Hey @DannyP I changed the stock valve covers for CB Performance...
here's a pic
It is not uncommon for us to pop a valve cover and find "witness" marks inside the cover from contact with a rocker arm. Stock steel we dent with a ball peen hammer, billet we mill clearance on the end mill.
@DannyP I do the same, either pen/paper or white board so I don't forget where I am at.
@chines1 posted:It is not uncommon for us to pop a valve cover and find "witness" marks inside the cover from contact with a rocker arm. Stock steel we dent with a ball peen hammer, billet we mill clearance on the end mill.
@DannyP I do the same, either pen/paper or white board so I don't forget where I am at.
So you're thinking the push rods on #3 are a bit too long? If so, I don't have a mill machine to grind (hope that is the right terminology) down... What do you recommend?
Clearance the valve cover where you see it hitting. If you don't have access to someone with a mill, a grinder or Dremel will work fine too. It won't take much. We always re-paint the section that we clearance and recheck to see that we removed enough material.
@chines1 posted:Clearance the valve cover where you see it hitting. If you don't have access to someone with a mill, a grinder or Dremel will work fine too. It won't take much. We always re-paint the section that we clearance and recheck to see that we removed enough material.
Thanks you very much @chines1!
Touching it up with paint and then waiting for it to dry before you can run it takes too long. A permanent felt pen's quicker...
