buZy Posted August 1, 2005 Share Posted August 1, 2005 After hearing what seemed to be valvetrain noises decided to check valve adjustment. Here is what I found inside. Status: Hydraulic valves, No roller cam. Roller rockers die cast style. Alum heads, guide plates. No major wear on lifters or cam. No broken valve stem springs. No metal or debris in motor valley, heads. It all looked 'good' and clean. Did find intake #3 preloads VERY easy. Too easy I think. Could crank in all the preload by hand untill the lifter bottomed out. The others felt much more harder almost solid feeling and could not preload them by hand. What I mean by hand is turning the rocker stud nut with my fingers only. #1 intake and ex felt kinda soft but only half as much. I know this is hard to explain. Something is making noise. The noise has been going on for quite sometime now. Approx 800 miles. And is not load sensitive. This (#3 IN) lifter was on the drivers side of the motor. The side making noise before teardown. Question: Do I have a bad lifter or lifters? Can I replace all the lifters and still retain use of my existing cam? All lifters have a part number on them it reads... 99277 I'm far from motor savy but know some engine basics. Enough to know I have a very bad feeling about thi$$$...... Any help would be great. Grumpvette are you out there? Thanks! Quote Link to comment Share on other sites More sharing options...
awd92gsx Posted August 1, 2005 Share Posted August 1, 2005 When I dropped my engine in I kept having a valve that would keep going out of adjustment. Seems the locknut for the rocker wasn't quite locking very well. After replacing it I haven't had any troubles since. Quote Link to comment Share on other sites More sharing options...
jt1 Posted August 1, 2005 Share Posted August 1, 2005 A new rocker arm nut should take care of it. It doesn't take a lot of pressure to preload the lifter, but the nut should be "self locking", and you definitely shouldn't be able to turn it with your fingers. It's working loose as the motor is running. Get a new nut, most likely that will solve the problem. You want 1/2 to 3/4 turn preload after you can feel resistance spinning the pushrod with your fingers. John Quote Link to comment Share on other sites More sharing options...
buZy Posted August 1, 2005 Author Share Posted August 1, 2005 Should add that all the lock nuts were in place and not loose when I did the teardown. Its the type of locknut with the allen screw in the middle. I just found inconsistant lifter plunger pressures when preloading them and thought is this ok or are these lifters shot.. Quote Link to comment Share on other sites More sharing options...
waynekarnes Posted August 2, 2005 Share Posted August 2, 2005 old valve cover, top cut off ... or if you just want to make a mess .. .no valve cover ... use a heavy wooden dowel ( broom stick cut down will work ) ... engine running, at idle ... push down on the push rod side of the rocker arm with the dowel ... be careful ... hair back, short sleeve shirt .. watch and all rings, chains removed ... push hard ... if noise goes away ... lifter, push rod, worn or badly adjusted rocker arm ... same thing ... put dowel to the top of the stud holding the rocker arm ... be careful ... put your head down to dowel .. if you are daring ... put the dowel to the part of your face about 3 fingers out from your ear ... ( i use a towel or rag for cushion, when i was younger i just used my hand ) rest your head on the dowel ... move from rocker stud to rocker stud until you determine the knocker .. you might also want to pull off a spark plug wire, one at a time, put it back on, and move through all 8 of em, see if that makes a difference ... sometime when there is no fire in the hole, the ticking goes away ... when i got my z, was already a V8 ( it's a scarab ), engine was knocking and clicking ... did all that stuff ... eventually found it had a cracked head engine was full of carbon ... i shoveled it into a half gallon milk carton ... filled it a little over half way ... sounded and acted just like a collapsed lifter or bent push rod ... good luck .. Quote Link to comment Share on other sites More sharing options...
jt1 Posted August 2, 2005 Share Posted August 2, 2005 If the nut wasn't loose, then it does sound like a bad lifter. You can replace the single lifter or the whole set on your existing cam, you just need to use cam assembly lube on the new ones and go thru the cam breakin procedure just like you've installed a new cam. Use assembly lube, crank and bring motor to 2500 rpm immediately with no idling, stay at 2500 rpm for 30 minutes, shutdown and change oil and you're good to go. Use a oil that has zinc in it, like Rotella diesel oil or Mobil one for the breakin and it's a good idea to keep using it on a flat tappet motor. The new oils with the sunburst logo are non zinc and intended for hyd roller motors, they don't do well in flat tappet motors. John Quote Link to comment Share on other sites More sharing options...
Pyro Posted August 2, 2005 Share Posted August 2, 2005 I hate to say it but..... Every time I had a problem like that it was never a "bad lifter". For me, it was a cam going flat and the start of a cone on the lifter face. And don't forget about the engine bearings eating all that metal. It makes me shiver. And a simple cam change never fixed it for long. My engines always needed a full rebuild to make it right again. I hope I'm wrong in this case. Don't kill the messenger. Quote Link to comment Share on other sites More sharing options...
buZy Posted August 3, 2005 Author Share Posted August 3, 2005 Yea I know.....Gives me nightmares at night. Killing my motor would put the Z down for I don't know how long, years. Like I have 3-5 grand on tap at all times. Not! OK keep the faith...Right now as we speak I am checking cam lobe lifter heights at the push rod end with no rocker. A 10yr experienced GM mechanic friend told me to do this. Did cylinder #1 tonight for a baseline test. This takes a lot of time even with a proper dial gauge setup. Switching between IN and EX I could repeat the numbers within .002 max tolerance. I hope my measuring like this will be 'tight' enough....? Anyone care to weigh in on that would be a great help. Also check all push rod lenghts, clean out with air. Next rocker stud heights and fitment. Broken valve springs. Lifters I never got the story on fully. You can have a bad lifter inside take it apart and it looks fine. Said they are very high tolerance when it comes to bleed down rates. I know little about any of this stuff. Also said the lifter face could look normal but you could still have a cam lobe going flat and not know it. That is why I am checking the cam. Quote Link to comment Share on other sites More sharing options...
jt1 Posted August 3, 2005 Share Posted August 3, 2005 Buzy, you're doing the right thing. About the only way to tell if a lifter is bad is if it has crud in it or the face is worn. If the internal clearances have opened up you can't tell it, except by process of elimination like you're doing. Checking the lobe lift is by far the most important. +/- 0.002 is plenty close, if a lobe is going flat you're talking about 0.050 to 0.100 or more. Hope you find a simple problem, not a bad one. John Quote Link to comment Share on other sites More sharing options...
buZy Posted August 8, 2005 Author Share Posted August 8, 2005 Project Status: Measured cam-OK. Took apart and cleaned out lifters on 1 3 5 & 7. Set all valves at 3/4 turn and used blue loctite on the jam nuts. Everything looks good so far. Quote Link to comment Share on other sites More sharing options...
buZy Posted August 9, 2005 Author Share Posted August 9, 2005 Ok finished putting eveything back together and ran the motor.... Final Status: Motor runs better than ever. Power smoother and more even. The noise heard before is now gone. All valves inspected running like they should. Tested in 93F heat today and drove it for a few hours. Looks like it just turned out to be only an adjustment issue. Better safe than sorry. At least now I know more about the motor than before. Thanks for the input guys. Quote Link to comment Share on other sites More sharing options...
jt1 Posted August 9, 2005 Share Posted August 9, 2005 Good deal!!!! Glad it was minor. John Quote Link to comment Share on other sites More sharing options...
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