[mizhele]

hello ive been doing some reading and saw an artical that noted different cams for the 240z require different lash settings...(actually i was reading the new VIC>BRIT cataloge and saw that the cams they sold reqiure lash of .006" int.and.008"exh set hot....so heres my thought since no matter how perfect i set the lash on my 71 240z it still makes alot of ticking...set hot or cold...ive set them so many times i can do it in under 5 minutes and getting sick of it,,anyway how if there is any way , can i tell if ive got the original cam or an performance cam,, are they marked ?? any posible way to tell...??? anyway just was think about this while watching the florida gators/seminoles play foot ball..and thought i'd run this by the z gods see what they say...thankyou michele

 

[Zoholic]

Hello Michele
I have A hi-proformance cam in my car & the valve's are always ticking know
matter how much I adj. them kind of annoying. I asked around & I was told
with A proformance cam there is nothing you can do about the ticking.
Keith

 

[Jason k]

Wedge the chain with wood and pull off the cam pulley,if it is a regrind they are usually stamped on the nose of the cam with a number,or letter number sequence.Cylemer,hanes manuals have this procedure outlined,the tough part is getting a piece of wood the correct size(it just should fit between the chain and rails with enough pressure to hold the chain in tension).Regrind cams usually cary such a steep ramp that they cause the rocker to get bounced around.Set the wipe pattern then adjust the valves,beyond that you'll just have to live with it if it is indeed a aftermarket grind.Stock valve trains where never quit in these motors to begin with especialy if you are used to new hondas or toyota 4s.Remember this engine design dates from the late sixties.Try listening to a another Z or 4cyl L motor to see if yours is really making an unusual amount of noise.I'm assuming that as much time as you have spent under your valve cover that any unusual wear patterns on the cam or rocker would have been noticed so at this point if the noise is excessive try replacing the mouse trap springs and or have your valve springs tested at a machine shop and replace them if not up to spec.You can do this with the head still on the motor using compressed air to hold up the valve but I like to take the head off so i can relap the valves and inspect the chambers if i have never been in this motor before.

 

[kzracer]

I doubt that the cam or lobes are bad, or that you can't do anything about it. The main problem, as far as I can see, is the fact that a lot of aftermarket cams have different base circles on the lobes than the factory stock measurements. This will affect how the lobe rides on the rocker arm. If the cam lobe rides off the end of the rocker arm, it will click. If the lobe hits the beginning part of the rocker arm, it will click. This is why when you are assembling an engine such as ours, or even replacing the cam and rockers, the components should be checked through a manual rotation of the upper end to check cam lobe wipe patterns. If these components are not checked, eventual destruction of the cam and rockers is inevitable. This wipe pattern can be altered by the use of taller or shorter lash pads. I have always used Nissan cams for this reason, and also that their metal quality is usually better. Something to think about....

 

[mizhele]

Re:thankyou

thankyou guys..you've been great help i will check swipe pattern and look for a regrind stamp on the front of the cam...thankyou again....michele