hey does anbody know what the valve clearance for inlet and exaust on a A12 is ment to be.

got the manual here:

says:

rocker arm to valve stem clearance
hot .35mm (.0138in)
cold .25mm (.0098in)

obviously same for in/ex as this is all thats specified

inlet 10 thou and exhaust 12 thou. Thats what they were when I did my apprenticeship with Camden Datsun Centre. Make the feelers a really tight fit, if its a loose fit they rattle

.10 and .12 would be OK if set when engine is cold ..

I have the Nissan A12 factory manual. It agrees with 1200rc:

Hot:
intake: .35mm (.0138)
exhaust .35mm (.0138)

Cold:
intake: .25mm (0.0098)
exhaust: .25mm (0.0098)

But Clymer and others say don't set it cold -- always Hot. When I used to do it, I did .013 in. cold, they were quiet. I always looked for a semi-tight fit (some drag, not loose, but not a really tight fit).

i've always had a fair bit of noise from my rocker cover despite adjustments (both hot and cold) to the workshop specs.
i assumed it was a normal A series trait.
Had the rocker arms lash pad re-surfaced. Still noisy.
Then again with big bore extractors and a 2 inch exaust i've had to get used to industrial deafness issues.
these datos were never designed to be a refined luxo cruiser! Things are a fair bit worse now with the variety of mods i've done.

A12s normally have zero rocker noise. Very quiet. In fact, when new with the factory muffler, you could barely hear a 1200 idling.

I have heard some noisy A-engine rockers, but usually something was worn out, like maybe one or two of the eight rockers were tapping.

Hey HOP,
I recently had an A12 that was in a Datsun 1000 that the owner could not get rid of tappett noise. The problem was that the bolts holding the rocker posts had started to pull out of the aluminium threads in the head and where moving up and down. It didnt matter if you set them to 10 thou or 20 thou they still rattled. A set of helicoils solved the problem and the noise
It may be worth a look, but dont try and tighten them anymore, cause if this is the problem you will strip them out, take em off and have a look. Or when its running with the rocker cover off there may be oil seeping or squirting out between the centre rocker towers and the head cause this is where the oil feed comes up. While the Rocker cover is off DONT rev the engine as it will get pretty messy. Those newer measurements would probably be right. The ones I gave where when they were new and from a workshop manual from Capital motors from the 70's. These days with the age on the car and engine and valve and seat wear etc, they would probably need a bit more clearance. and when we used to do them new they were done hot
Hope this helps