Here's a good read...

And my setup with the tools and the "crossing them off" board I put under the passenger's wiper blade. 

 

 

As I was thinking about this a bunch of memories passed through my head in voice over type thoughts.

"Is this one exhaust or this one?"

Do they just alternate from here?  Exhaust - intake - exhaust - intake...  No?  Crap.

The engine's tilted.  Up is not Up".

Is this still hot?  Should I start over?

It was perfect before I tightened the lock nut, now it's too tight.

Does it matter if it's hard to get the feeler gauge in?

Am I scratching the cam lobe with the feeler gauge?

Where's my small sledge, I don't want to bleed anymore.  

#1 is a B___h!

I should have wiped that oil off the edge before it dripped down the side of the engine.

Wow, I really wacked something when the nut came loose.  Hope nothing got bent.

I could have just taken my time setting them cold, then rechecked them when they're hot.

 

And that's just in the first hour.

 

As I was thinking about this a bunch of memories passed through my head in voice over type thoughts.
"Is this one exhaust or this one?"
Do they just alternate from here?  Exhaust - intake - exhaust - intake...  No?  Crap.
The engine's tilted.  Up is not Up".
Is this still hot?  Should I start over?
It was perfect before I tightened the lock nut, now it's too tight.
Does it matter if it's hard to get the feeler gauge in?
Am I scratching the cam lobe with the feeler gauge?
Where's my small sledge, I don't want to bleed anymore.  
#1 is a B___h!
I should have wiped that oil off the edge before it dripped down the side of the engine.
Wow, I really wacked something when the nut came loose.  Hope nothing got bent.
I could have just taken my time setting them cold, then rechecked them when they're hot.
 
And that's just in the first hour.
 

LOLILOLOLOLOLOLOLOLOLOLOLOLOLOLOL!!

I’m amazed how you managed to list my exact thoughts! [emoji1787][emoji1787][emoji1787][emoji1787]

Brilliant!

Hello,

 

I have a Datsun 240z 1973, when I bought the car I was informed the previous owner may have added a "hopped up cam". Since owning the car I have had issues with rough idle and pinging and I am curious if this some of this could be related to the valve timing. I have not checked the Valve timing but I am not sure that stock numbers will work if the cam was changed from Stock. Curious advice for a Zcar novice.

 

Thank you for your time,

 

Josh

1 hour ago, paulreverex said:

Hello,

 

I have a Datsun 240z 1973, when I bought the car I was informed the previous owner may have added a "hopped up cam". Since owning the car I have had issues with rough idle and pinging and I am curious if this some of this could be related to the valve timing. I have not checked the Valve timing but I am not sure that stock numbers will work if the cam was changed from Stock. Curious advice for a Zcar novice.

 

Thank you for your time,

 

Josh

The cam should have come with a card showing the lobe profiles, lobe centerlines, lift, duration and recommend lash settings. If you didn’t get it with the car, see if you can get the cam manufacturer and cam type, then contact the manufacturer for the details.

6 hours ago, Racer X said:

The cam should have come with a card showing the lobe profiles, lobe centerlines, lift, duration and recommend lash settings. If you didn’t get it with the car, see if you can get the cam manufacturer and cam type, then contact the manufacturer for the details.

Just posted mine in another thread, good timing!

 

I think two threads are running the same conversation?

I just caught that. Thanks!

For what it is worth, I have done a cold lash to the 008/010 dimensions on my engine.   A year later I pulled the valve cover one afternoon and checked it, it was still beautifully set and had not moved.  I trust the 008/010 method cold.  I can take my time and really get a uniform feel.  Also, the biggest challenge for me is to ensure the cam lobes are in the round section. Constantly bumping over the engine is a pain. Removing the plugs helps tremendously.  But trying to remove the wires, valve cover and plugs and get your bump start trigger hooked up is hard to do with the engine at a uniform temp for the 12 valves.  

 

Go cold and take your time. I think it will be fine. 

I put together a little spreadsheet that I think captures much have what's been provided here.  Although I like the cardboard, I think this may work as well.

Let me know if I should had any other notes/comments.  It prints on two sheets, so you'll have to tape them together.

 

280Z Valve Adjustment Chart v2.pdf

Edited February 28, 20223 yr by HappyZ

On 9/14/2021 at 5:55 PM, siteunseen said:

And my setup with the tools and the "crossing them off" board I put under the passenger's wiper blade. 

 

Any pics of the adjustment operation?

The above tool set is helpful - The Nissan 75 manual has no detail on the process, that I can find beside this pic in the Engine Mechanical section

I tried to figure it out from the pic of the valve layout. Not clear to me, besides that the 4 elements on the left are the adjuster

Mine are all way too tight - can barely get a .010" feeler in there (checking #5 exhaust here, as that cylinder only had 145psi vs 168psi on the other 5)

Edited March 21, 20232 yr by HusseinHolland

The low clearance could be because the valve seats have worn.  Maybe due to unleaded fuel on old seat material.

People use brute force on the locking nut with a wrench and suffer busted/cut knuckles.  The parts up there are sharp.  I found that a small sledge hammer, like a 3 lber, used to tap on an open end wrench on the lock nut worked well for loosening.  There's room for an open wrench on all of the locknuts, you don't need the crow's foot adapter unless you want to get precise on tightening torque.

It's about as simple as it looks.  There's a threaded stud with a locknut.  Loosen the locknut, turn the stud, tighten the locknut, confirm lash.  After a few you'll realize that tightening the locknut pulls the stud up and reduces clearance a little bit.

There's a tutorial out there somewhere with pictures.  Can't remember the name, it might actually be linked in this thread somewhere.