1rad280 Posted March 23, 2008 Share Posted March 23, 2008 My 1975 280z is finally running but after letting it run for a while it started clicking from under the valve cover.So I took the valve cover off I found a valve rocker guide had fallen out of the 4th valve spring from the front. Ok, when bumping the starter over with the key with the rotation of the cam lobe the rocker arm pops up and hits the cam lobe. What will cause this? Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted March 24, 2008 Administrators Share Posted March 24, 2008 My 1975 280z is finally running but after letting it run for a while it started clicking from under the valve cover.So I took the valve cover off I found a valve rocker guide had fallen out of the 4th valve spring from the front. Ok, when bumping the starter over with the key with the rotation of the cam lobe the rocker arm pops up and hits the cam lobe. What will cause this? What exactly are you describing? We can’t make out any thing you just said. Your terminology does not make any sense of what could be taking place. When talking about engine internal parts, or any form of communication at all, we need to be speaking the same language for both parties to fully understand each other. Internal engine parts all have names and we all know those parts by those names. If you are calling those parts by names other than what we know them as or making up names for them because you don’t know what to call them, we have absolutely no idea what you are saying or trying to convey. Here is a list of the parts of the valve train for each valve, starting at the valve and working our way up to the to the rocker pivot. The Valve itself. Valve spring. The valve spring retainer is the disc on top of the valve spring. The keepers are inside the retainer and hold the retainer on the valve spring. There is lash pad that sits on top of the valve stem, in side the middle hole of the retainer, under the rocker tip. Then there is the Rocker arm itself, the cam lobe “wipes†across the rocker wipe pad on the rocker, then the rocker pivot which is height adjustable and is used to adjust valve lash at the cam to rocker interface. Now, using those parts description as listed above, could you please rewrite what is taking place so that we can better understand what is you are trying to convey? Quote Link to comment Share on other sites More sharing options...
OlderThanMe Posted March 24, 2008 Share Posted March 24, 2008 "rocker arm pops up and hits the cam lobe" What does that mean? The rocker arm almost always is touching the cam or within ~.010" of touching the cam... How can it "pop up" and touch the cam lobe? It makes no sense. Quote Link to comment Share on other sites More sharing options...
woldson Posted March 24, 2008 Share Posted March 24, 2008 I'am actually looking forwrad to the concludetion on this subject. Quote Link to comment Share on other sites More sharing options...
1rad280 Posted March 24, 2008 Author Share Posted March 24, 2008 Ok, While I was starting my 280 it started pecking from the valve cover. I remove the valve cover and found the lash pad off of the 4th valve, from the front of the engine just laying on the head.I replaced it and now when the tall part of the cam lobe passed the rocker arm, it makes a loud pop, could the rocker arm be to far out of adjustment Quote Link to comment Share on other sites More sharing options...
G.I.jonas Posted March 24, 2008 Share Posted March 24, 2008 I'am actually looking forwrad to the concludetion on this subject. Quote Link to comment Share on other sites More sharing options...
woldson Posted March 24, 2008 Share Posted March 24, 2008 What is the tolerence at the "4th valve"? Quote Link to comment Share on other sites More sharing options...
1rad280 Posted March 24, 2008 Author Share Posted March 24, 2008 It is hard for me to explain it sorry. Quote Link to comment Share on other sites More sharing options...
1rad280 Posted March 24, 2008 Author Share Posted March 24, 2008 it should be 0.010 in. I havent had time to check valve clearance yet. Quote Link to comment Share on other sites More sharing options...
bucket240z Posted March 24, 2008 Share Posted March 24, 2008 I actually have the same problem as you. After adjusting the valve clearances the problem still persists. Next i am going to check the valve spring and make sure its not shot. My uncle said that is probably the problem. Hope that helps. Quote Link to comment Share on other sites More sharing options...
sweetleaf Posted March 24, 2008 Share Posted March 24, 2008 Did you replace it with the same pad? Is it seated all the way and in the correct orientation? Is it damaged in anyway? Ok, While I was starting my 280 it started pecking from the valve cover. I remove the valve cover and found the lash pad off of the 4th valve, from the front of the engine just laying on the head.I replaced it and now when the tall part of the cam lobe passed the rocker arm, it makes a loud pop, could the rocker arm be to far out of adjustment Quote Link to comment Share on other sites More sharing options...
woldson Posted March 24, 2008 Share Posted March 24, 2008 Valve might be sticking in the guild. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted March 24, 2008 Share Posted March 24, 2008 Bent valve perhaps? Evan Quote Link to comment Share on other sites More sharing options...
1rad280 Posted March 24, 2008 Author Share Posted March 24, 2008 It looks like the valve is moving freely.If it was a bad spring would it not close all the way?I will set the valve lash clearance and I will post back later. Quote Link to comment Share on other sites More sharing options...
Administrators BRAAP Posted March 24, 2008 Administrators Share Posted March 24, 2008 Broken spring maybe? Quote Link to comment Share on other sites More sharing options...
1rad280 Posted March 24, 2008 Author Share Posted March 24, 2008 while at home I manualy turned the engine over and noticed when the 4th exhaust valve was compressed it stayed down until half way of the next revolution and the valve would pop back up and kit the rocker arm. So is it a bent valve? Is the valve sticking in the guide?Or broken valve spring how do I tell? Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted March 24, 2008 Share Posted March 24, 2008 As per recent requests... THIS IS A GUESS! It sounds like a bent valve to me. A broken spring should be fairly obvious IMHO, so I'd take your valve out if you can and roll it on a piece of glass to see if the shaft is bent. I suppose it could be sticking in the guide, but I'm betting on bent valve. Quote Link to comment Share on other sites More sharing options...
1rad280 Posted March 24, 2008 Author Share Posted March 24, 2008 This engine set for 15 years. I have a nother question are these engines interference engines? Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted March 24, 2008 Share Posted March 24, 2008 this engine set for 15 years I have a nother ? are these engines interference? Um, does not compute. Please restate the inquiry... EDIT: Mmm double post. Never heard of an interference engine. Handing this one off... Quote Link to comment Share on other sites More sharing options...
1rad280 Posted March 24, 2008 Author Share Posted March 24, 2008 An interference engine is one that if the timing would get off or a valve would get stuck the piston would touch the valve.. bend a valve. Quote Link to comment Share on other sites More sharing options...
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