GStwin.com GS500 Message Forum

Main Area => General GS500 Discussion => Topic started by: Richmore on January 24, 2006, 08:37:07 AM

Title: Hmmm... Unsure on valve adjustment
Post by: Richmore on January 24, 2006, 08:37:07 AM
Ok, so i have read the valve adjustment HowTo and it all makes sense apart from the very end where it reads:

   
QuoteSlide a thickness gauge between the camshaft and the shim.
There should be a gap between 0.03mm and 0.08. If it is out of specs, replace the shim with a 0.05mm thinner or thicker.


I have adjusted valves on numerous cars (SOHC) many times but the process on the GS500 seems slightly different. What exactly is replaced if the clearence is beyond tolerance, on a car it is just a case of adjusting the rocker arm tappit.

Any help, i would really like to know a little bit more about what i am doing before i wade in and destroy.  :laugh:


I am getting "popping" at idle and so i will be checking/replacing:

Thanks in advance,
Richmore
Title: Re: Hmmm... Unsure on valve adjustment
Post by: Stephen072774 on January 24, 2006, 08:42:40 AM
The valve shim is replaced.  Shims come in different thinknesses so the tolerance stays between .03 and .08
Title: Re: Hmmm... Unsure on valve adjustment
Post by: Richmore on January 24, 2006, 11:08:45 AM
I know how dum this is... but what exactly is a valve shim?

The impression i get is that it is some sort of spacer, are they adjustable at all or is it simply a case of "if the clearance is to large/small replace the shim"?

and to think my gf let's me loose on the car... :laugh:


Thanks,
Richmore
Title: Re: Hmmm... Unsure on valve adjustment
Post by: Admiral Crunch on January 24, 2006, 11:13:35 AM
The shim is a coin-shaped block of metal.  It is available in different thicknesses.  If the distance between the cam and the shim is out of spec, replace the shim with a thinner or thicker one as needed.

If you have a speedy connection, download this great how-to video (http://www2.newnanutilities.org/~ewhitley1/vids/GS500ValveAdjustment.wmv) made by Kerry.