Valve adjust - hot or cold?

[Kerrigan]

Got a '71 L20 engine in the FairladyZ.

The local Z mechanic, very highly thought of by the local Z car owners, when I asked him "valve adjust hot?" he said "nope, not necessary. Always do them cold."

Okay.

What is the pro and con of adjusting them hot vs cold? Would the result be the same if I had him do them as he will be adjusting them cold or should I just look for someone else?

I can guarantee if I try it they will be screwed up ... !!

[Gav240z]

It's more a preference of a personal nature, i think hot you'd get a better setting more accurate anyway. As the engine get's hotter the metal of course expands and therefore the adjustment is more accurate hot because that's how the engine is most of the time.

Cold is easier for newbies because time isn't againt you although I've never tried it cold but I will when I install the new camshaft.

PS: You can find this discussion in the search facility under forums then search.

[280zx Fever]

If you do them cold you have to make the clearance's loose.

If you do them hot you have got time against you !

I just helped my mate do his on his L20b both hot and cold and i burnt my hands heaps of times

Ok ill hijack the tread now - Valve clearence on the L29 between the cam and the rocker or the rocker and the valve ?

[TKR514]

Ya do both.

The suggestion in the FSM on mine says do it cold for an approximate setting then do a hot clearance. Mine have never been way out-of-spec during the hot test if the cold settings were accurate. Now I just do the hot test and it seems to be fine.

[dogma420]

every motor is different on the differences of hot and cold clearances. You can check the clearance hot, and then cold and minus the difference when doing the valves cold.

Since every motor is different, its recommended to do them hot.