Loud ticking/knocking noise.

[disepyon]

Thanks for the help all.

I believe I found the Cause of the symptom. The rocker arm for exhaust valve to cylinder one is very loose. Keep in mind that this is after ive adjusted and checked like 6 times and its still loose. Any ideas on why its so loose? Ive checked all the other arms for the other valves and they are not this loose and does not make a clicking sound like this. Could it be a worn shim or something? My terminology may not be right so correct me if i am using wrong terms to describe.

Here is a video i made:

<iframe width="480" height="360" src="http://www.youtube.com/embed/ageYcen1mkA" frameborder="0" allowfullscreen></iframe>

[Zed Head]

Feeler gauges too wide and you're measuring the wrong clearance? Measuring lash on a rocker arm or cam ridge? Maybe the rocker arm retainer spring is tight enough to give you a false reading on your lash. Looks like you're pressing pretty hard to get the rocker arm down. You're pressing against the retainer spring pressure from the other side, I assume. Is it out of its groove or bent?

[disepyon]

With the engine hot i am using the correct gauges like the manual said and what that guy said in the links i posted in my first post: .012 exhaust and .010 intake in inch.

I know on a lot of engines you measure and do the valve lash when the engine is cold and thats it. But for some reason this engine needs another adjustment at hot. the links i posted on how to measure is not correct i am starting to think, or it might be. I have two different manuals. One says to measure at cam shaft lob and rocker arm. The other manual says to measure at the ends of the valve stems and rocker arm tips. How do i know if something is bent with out taking apart things?

[Zed Head]

You should use the numbers you've shown between the cam lobe and the rocker arm. My point was that maybe you're not getting a true measurement between the actual rubbing surfaces of the cam lobe and rocker arm. The gauge might be rubbing on a high point, or the retainer spring might make it feel like a tight fit when it's not. If one is loose they should all be loose, unless your lash measurement was incorrect.

The procedure is in the Nissan FSM. The .012 and .010 measurements are between cam lobe and rocker arm when warm. Recheck after you tighten the locking nut since the tightening will decrease the lash a small amount.

For what it's worth, from a materials science standpoint, assuming that the components all expand at the same rate (they will since they are made of the same metal) and the running temperatures of the components are essentially the same (why would they not be), there's no reason not to do it cold, using the .008 and .010 numbers from the 1976 FSM. It's easier, less painful, and you can take more time to get it right.

[disepyon]

Thanks for the reply. I just went out to check the clearance on cold settings since the engine is cold and hasnt been running since yesterday. When i checked all the exhaust clearances with .010inch, only that one rocker arm assembly and cam lob wont allow me to fit my gauge in, all the others slid in fine. So i think its like what you said either something isnt seated right or something is bent giving me a false reading. everything looks seated right though.

[olzed]

Are you saying you can't get that gap any tighter?---. Very odd. Are you measuring at the heel of the cam? Rotate the cam slowly with the feeler in place,to find the most loose spot. The lobe may be dodgy. Doubt that though.

I always measure the gap at the cam lobe. Works for me. I do it cold, and have never had any issues.

Is the noise in the vid. similar to what you are hearing with the engine running? Why does removing a plug wire make the noise go away? Got me baffled.

Edit. You clicked the send 1 minute before me . Well it would seem to be something out of kilter . Obviusly the gap is now tighter. As I suggested ---try rotating the cam.

Edited June 2, 2012 by olzed

[disepyon]

I havent readjusted anything yet. I just checked the clearance to see if the gauge would fit or not on cold settings. Honestly i dont think it matters if you measure directly at the base of the heel or off to the side like the manual talks about when the piston is at top dead center and the cams are point upright on its side. But yes i did rotate and it did not matter, the gauge would still not fit.

I think i will readjust again with cold settings one last time and leave it and forget about doing it hot. just go one measurement step down for that one rocker arm and cam lob to get a tighter fit and see it that works. Honestly i really dont care much for this motor, i have a ls1 i want to swap in, so if over time this motor goes out on me thats ok, i just wanted to know the cause of this problem and we figured it out, im happy. Ive never seen anybody adjust clearance while hot because if you think about it, your just making a bigger gap for when the engine cools down and the metal shrinks.

It is the exact noise i am hearing, just a lot louder. I dont know either why combustion would affect it. Maybe with combustion the valve has a lot more force acting upon it.

[Zed Head]

Actually sounds even odder. He's (You're) saying that the "loose" one is too tight at the cam lobe. Therefore all of the others should be even looser. Something's off.

If you want to be sure the retainer spring isn't too tight, press down on the rocker end like you did in your last video, while you slide the feeler gauge in. That will take the retainer spring out of the situation. It will be crowded with a screwdriver in the way, but worth a try.

Edit - Added a You're...

Edited June 2, 2012 by Zed Head

[disepyon]

so the largest size gauge that slides in there right now with out me doing a readjustment is .008inch which is way off than the .010ich correct gauge on cold setting.

[Diseazd]

Why not pull the rocker and take a look for wear on the wipe surface or where it makes contact with the lash pad. If the cam has worn into the rocker wipe surface (cupped), that could cause this phenomenum. I've never encountered such wear, but it could happen I guess.

[disepyon]

I am thinking about doing it real quick. I just found this link on how to remove that stuff: http://www.oocities.org/inlinestroker/seals.html this helped me understand better what the manual is talking about

[olzed]

Good link. of course you don't need to stuff rope in the cylinder unless you are going to remove the valve keepers and springs. Section 12 in the link-- Beware of the lash pad flying out and dissapearing if your screwdriver slips off the valve collett. Throw a rag over the valve you are working on to contain bits that can become airborne. If they take off they are very difficult to find again. Been there.