The valvetrain on my 88 IROC had developed a fairly audible tick so I decided it would be a good idea to adjust the valves.

I searched for valve adjustment procedure with the motor not running and found this by Vader. I know the procedure is correct and I followed it to the tee, but now the valvetrain is clacking like it's gonna fall apart. It's obviously too loose, I went through every cylinder at least twice and checked them again by turning the motor over twice by hand. Everytime I came back to the same cylinder to check whether it was still tight, it would be loose again. I can wobble the rockers and spin the pushrods while the cylinders are at TDC on compression. I don't want to adjust the valves with the motor running because I have to pull the heater hoses off and out of the way to remove the passenger side valve cover. The coil bracket is also in the way since it pinches the wiring harness down on the cover. To remove it I have to loosen 2 intake bolts that leak antifreeze when loose. As you can see adjusting the valves with the motor running is not really an option in this case.

Any suggestions as what I should do? How much oil does the motor spray with the V/C removed? Can I just stick a piece of cardboard on the edge of the head to prevent oil from going all over the place?

 

Basic rule of adjusting valves, the lifter has to be on the base circle of the cam, not on the ramp of the lope at all. The valve has to be completely closed. Pick valve to start on & spin the engine over by hand (removing spark plugs helps a great deal). Watch the valve spring as it decompresses (gets taller) after it stops turn a tad farther & adjust that valve. After you have done it a few times you can eyeball the spring & tell if its open or closed.

BTW it sprays alot of oil without the covers on.

 

I'm pretty sure each lifter was on the base circle of the cam while I was adjusting the corresponding rocker. I could tell that the valves were closed by looking at them, but whenever I came back around to them they seemed loose again, especially when the one valve was closed and the other open. I'm wondering if my timing chain is possibly stretched so much that I wasn't completely on the base circle with the timing mark on the balancer at TDC on compression. I know the timing mark is spot on because I have used it to set my timing before and the car ran perfectly fine, just with a little bit of valvetrain noise.

I read in another place that I shouldn't go back and check for zero lash again because the lifter begins to bleed and you can spin the pushrod again. However, if I had overtightened the rockers then it would have run but not made any noise. Right now it's running fine but it's noisier than hell. I know driving it like this will ruin things in short order so the car will remain parked until I can readjust the valves.

I originally used the method that involves turning the crank 90* and adjusting the valves by firing order (1-8-4-3-6-5-7-2), and I did it twice. Now I'm thinking I will go back in the morning and try the other method where you adjust certain valves with the engine at TDC compression on #1 then turn it over 360* so it is at TDC compression on #6 do the remaining valves. If that doesn't do it, then it's time to spill so some oil and do it with the engine running.

 

Rick has it right. The way I do mine is turn the engine over until the exhaust valve starts to open just barely. Then on that same cylinder adjust the intake rocker. Next, turn the engine over until the intake valve of that cylinder opens all the way up and just almost closes. Just before it closes adjust the exhaust rocker.

When adjusting the rockers tighten them until there is no up and down movement or "lash" on the pushrod then a 1/2 turn.

Go through all of them the same way and it should work out fine.

 

Thats the way I always do it ...simple and goof-proof. Just like a solid cam but without the measuring

 

At Zero lash should you be able to spin the pushrods? The way I am reading this is some are saying yes and some are saying no. This is the last thing I need to do before installing my 350 so I truley appreciately the help. Thanks!!

 

at zero lash and asking if the push rod spins or not is like asking if midnite starts or ends the day. it's the point of transition, basically when you reach the zero lash point the push rod will stop spinning because preasure is now being applied to the lifter cup. you have to watch that the lifter it self doesn't begin to spin and fool you into thinking you've not reached zero lash. if you're using stock rocker nuts you can get pretty close by setting the nuts .2 down from the top or end of the stud and set them running after it fires

 

I finally broke down and tried to adjust the rockers with the motor running. I went through them one at a time, backing the nut off till the rocker started ticking then tightening it down to the point where it quit ticking. Now here's what confuses me - I can't put any preload on the rockers at all . If I tighten it any further past zero lash, it starts running real rough and makes a lot of 'clacking' noise, distinctly different from the ticking noise you get if the rockers are too loose, but it goes away in a few seconds. What's even worse is that if I rev the motor even slightly to like, say 2000 RPM, the clacking noise comes back and gets real loud. This motor is not running like it did before I attempted adjusting the valves!!

Another thing I noticed is that when I first started it up, none of the rockers were squirting any oil, at least not enough to be noticeable over all the oil that's already in there. Finally one of them started squirting oil like crazy. The others still aren't squirting anything. Does this indicate collapsed lifters or something? If the lifters are indeed collapsed, how do I get them to pump back up.

Thanks in advance

 

When you first start up a motor its normal for oil not to come out of the pushrods until its fully warmed up.

The only thing that comes to mind is that maybe you're putting downward pressure on the rocker as you tighten it? Gently place the socket over it and dont push down AT ALL or it'll appear tighter than it actually is. If the rockers are too tight they wouldnt make noises - your car would just run like CRAP and probably not idle.

 

The squirting indicates nothing. Ignore it.

Do the zero-lash thing, where you back each one off until it ticks and tighten until it just stops. As quick as you can, do all 16. Don't worry about preload at that time, just zero-lash them quickly. That minimizes the mess. Then shut the engine off and put your half turn or whatever of preload on them, and put the VCs back on and all that before you start it up again. There's no need for the engine to be running when you do that part.

What's happening, is that when you do the preload with the motor running, it takes many revolutions before the oil that's trapped in the lifter gets squeezed out by the new preload. During that time, the valve is being held open by a lifter that's too tal to let it close. It's not so bad when you do that to an exhaust; but get a couple of intakes doing that, and the motor will barely even run.

 

Or another thing, if the rockers are too tight and you adjusted them with the engine off, the engine may not start. OKay, I'm having the same prob with my V6 and I am at a loss. I've done it according to TomP's shop manual procedure, and I've done it with the engine running to the point that the engine stalled if I tightnened a few of the rocker nuts any tighter. After that, I went back in again and loosened up the rockers that appeared to be too tight (the nuts were way lower on the studs than the others) and backed them off until the nuts were pretty close to being at the same level as the other nuts. The valvetrain still clicked, so I went in again and tightened each rocker down another half turn, but that's when my alt went when my batt died and I could't run the engine, and to make matters worse, the bracket for the alt broke so I have no serpentine belt to drive anything. Am I on the right track here, or am I only screwing myself to the point that I'm going to need a new timing set?

BTW, I have done a majority of the adjustments with the intake manifold off so I could see that the lifters were on the base curve of the camshaft.

Oh, and while adjusting with the engine running, I lost like two quarts of oil, or at least one. It's super messy and there tends to be no place to put a rag as the manifolds/headers are the only place to rest a rag or something on. Besides, it produces a heck of a lot of smoke from the burning oil. (Cough, cough)

 

Thanks, RB. I'll try that today and see if that makes it any better. I hope it fixes the problem or else I'll have to pull the intake off and check the lifters and cam . More money down the money pit...

Maverick, you can do what I did to minimize the mess. I took a piece of cardboard about the length of the cylinder head and about 7 or 8 inches tall and stuck in the head so that it would catch all the oil squirting out. Worked just fine for me. Just a few drops of oil here or there but absolutely none on the manifolds .

 

I'll have to try it again when I get my exhaust system back together under there. *** knows I have enough cardboard laying around...

 

but I thought I'd chime back in tell you guys why I thought it was still all loose and noisy as hell. Turns out I had forgotten to take into account the disconnected AIR hoses coming off the manifolds. I broke the one way valve off one of them and completely overlooked the fact that it was actually an exhaust leak making all that racket. Talk about DOH!!!! I felt like such a dumba$$ after I realized this. And to think that I had been adjusting and readjusting the valvetrain for hours !!

 

damn dude lol...thats rough..i remeber one time i took the TB off and you know that little plastic vacuum line thats on the under side of the TB?..i forgot to hook that up and for the longest time (about a week) i couldnt figure out why it wouldnt idle under 1500
lol

Just a FYI...After reading what RB said

When i built my LT1 motor i lashed and preloaded the valves before i fired the motor...i tried to start it and had ZERO compression in any cylinder...i backed them all off and the motor got compression back...i go thtem to the point were the pushrods would come out of the lifters and started the motor...i lashed them all, then went back and loaded them all 1/2 turn..if u keep a little turning pressure on the wrench, socket or w/e, the adjusting nut will literally turn itself and the valve closes, so your loading it when the lifter is all the way in the bore....When i loaded an intake the motor did idle rougher for a couple seconds then smoothed out...i did all the valves and let the motor cool down cuz the rockers were getting hot to handle....I went back through and put another 1/2 turn into them and it idled rougher for a couple seconds then smoothed out....


Why in my case did it all work out RB?

 

There should be NO slop or slack in the rocker arms AT ALL. Once the pushrod stops moving vertically, try to move the rocker arm side to side. If it moves, you have to turn the nut another quarter to half turn tighter before the final loading of the lifter, however many turns it takes for you. That is the way I did it when the engine still ran .

On second reading of the new posts, I decided to keep this for anyone who needs a little help (Shrug)