Subject: Valve Clearance
Tom wrote:
> Today I checked the clearance on the valves, what I
> found was that the intake are .006 and the exhaust are
> .010. The "manual" that I have (DrDatsun) lists the
> spec at .008 for intake and .012 for exhaust.
>
> Should I reset them to the specs? Why may the PO have
> set them this way?
Hi Tom,
The PO may have wanted to increase the intake valve duration just a bit.
(Each .001 inch less clearance equals about one (1) degree of cam duration
increase.)
Valve specs for a cam in block engine (R engines) actually decrease
between cold and hot, (usually about .001 less) while overhead cam engine
valve clearances increase between cold and hot (usually about .002 more.)
Erring on the side of wider rather than closer is usually the best valve
setting.
The longer the dwell time (increased clearance) of the valve on the
valve seat helps to keep the valve head cooler (longer lived.)
Kim Blough
Idaho Z Car
2913 Garrity Blvd.
Nampa, Idaho 83687-2629
1-208-466-0004
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