Loud ticking/knocking noise.

[disepyon]

Took the exhaust and intake rocker arms off for piston 1. I do not know how to tell the difference between a good and bad rocker arm or lash pad. Hoping someone here could enlighten me. Do the springs and keys look correctly seated?

The red arrow points to the rocker arm for the exhaust that is causing the clicking noise (what i believe, wont know for certain unless i make the clearance smaller, run the engine and hear if the noise is gone).

So my plan is to readjust all valve clearances on cold. put everything back on and run the motor. If noise still persist the i will make the clearance between the rocker arm and cam lob for the exhaust valve for piston 1 smaller. Put everything back together and run the motor just to see if the noise is gone. If so, then i may just buy a new rocker arm and lash pad from the z store for $42.13. Is it ok to just replace one rocker arm?

[Zed Head]

Just stopping by...

Thanks for all the pictures. I haven't disassembled a good running engine so haven't really examined those parts up close. The wipe pattern on the rocker arms (where the cam rubs) looks centered and smooth, which is good. The lash pads with the close-up looks kind of worn, is that spot depressed or just looks worse than it is?

As I understand it, you can put new or resurfaced, rocker arms on an old cam, because the wear surface is perfectly smooth with no high spots to cause rapid wear. So a new arm and lash pad should work.

Looking at your pictures, I see the spray bars and wonder if it's possible that one got bent and is touching a valve retainer or rocker arm during operation. They're easy to bend. Worth double-checking.

Good luck with it, someone with more experience will probably be able to tell you more about the pictures.

[Diseazd]

Hard to tell for sure, but looks like an awful lot of wear (groove) in the exhaust rocker. I'd replace the rocker and put it back together. See if that fixes your problem. Check to make sure the oiler hole to that rocker is completely open.

[AZ-240z]

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.

I just had my valves adjusted, and agree with what Diseasd mentioned. The mechanic that did my adjustment popped out each rocker and checked the wipe surface for

pitting and wear. I watched the process and he said that a pitted wiper surface on the rocker could rapidly wear and damage a cam lobe. He began working in Datsun

dealerships and Z cars in 1973.

[disepyon]

Well it seems like you guys are right about the rocker arm and lash pod being bad.

I just got done readjusting all the valves and on that one bad rocker i went one size gauge smaller (.009inch). Started her up and it was completely silent, no clicking/knocking/ticking noise what so ever. However once it warmed up it began to make that noise. Not as loud as before, but still noticeable.

I guess ill go ahead and order a new rocker arm and lash pod tonight. Any of you know a cheaper source than TheZStore?

[disepyon]

Ordered from Black Dragon Auto instead of the Z store, cheaper. Now its just a waiting game to get the new parts.

[olzed]

Good that you found the problem.

[disepyon]

Update!!

I am proud to say that the new rocker arm and guide replacement is a success! No ticking/knocking anymore. Engine runs and sounds smooth and sexy.

Pictures of the new rocker arm and guide:

Sorry i do not have any pictures of it installed. I actually brought my camera out to the garage but was so excited and anxious that i completely forgot about pictures. It was tough getting the new rocker arm on. Had to really depress the spring just to barely slide the arm in.

Well thanks for the help everyone, its forums like this that keep me here.

[olzed]

Excellent result.

[240260280z]

I like happy endings.