adjusting valves

[Dreco]

I called Rebello to see what I should have my valve clearances at, and they said .008 at the valve (cold) , NOT at the cam. I only know have to check at the cam. Anyone know how to check at the valve???

Dave Record

1972 240Z rebello 3.0L

[Dreco]

Nevermind. I had someone clarify it for me. They measure at the valve underneath the rocker arm. They say it's more accurate.

[2ManyZs]

Hmm, stands to reason it could be done either way, but boy, you'd almost have to be a contortionist to do it quickly.....

Might be simple to do if the motor is out of the car on a stand, but doing it while it's in the car you'd almost have to stand on your head to make sure you were measuring it correctly..... Or maybe I'm just too tall or don't know the correct way to lean over the fender....

[JEFF]

I've always done it between the cam and the rocker arm with out any problems. Am i doing it the wrong way??

- Jeff

[2ManyZs]

Factory says to do it between the lash pad and the cam, so I don't think there is anything wrong with it. Six of one, half dozen of the other... It all amounts to pretty much the same thing when all is said and done....

To be honest, I don't see how it can be any more accurate the way they say, as you would be lifting the lash pad against the cam and could possibly get an erroneous measurement if the lash pad were not fully up against the cam(such as a funky wear pattern on a somewhat tired engine) so either way, you should get the same results.

And a hot lash adjustment will be somewhat more true to the valve adjustment than a cold measurement. Maybe that's why their measurements are done cold, they have the engine out on a stand where they can do their measurement without going into a circus contortionist performance....

[Dreco]

Well, these guys build one heck of a motor. Many years of research and development. Must be something to it. I was told they never measure at the cam. I'll give it a try.

[Alan Pugh]

From memory it's all to do with the distance from the cam contact point on the rocker to the pivot point, versus the distance from the cam contact point to valve. It's always much more accurate to do valve clearances at the valve. Having said that there is probably only a few ten thousandths in it.

Just my 10c worth.

Al.

[Dreco]

Thanks for refreshing my memory there Alan. That's how it was explained to me by the guys at Rebello Racing. It just went in one ear and out the other at the time.