<VV> Valve Guides

[Chris & Bill Strickland]

Ron, et al --

from  http://www.aa1car.com/library/ar696.htm:

Replacement guides come in various alloys and varieties including 
bronze, cast iron and powdered metal. Phosphor/bronze, 
silicon/aluminum/bronze and manganese/bronze are generally more 
expensive than cast iron but are harder and usually provide superior 
wear resistance. With leaded gasoline, bronze guides typically lasted 3 
to 5 times longer than cast iron. But with today's unleaded gasoline the 
difference in longevity between cast iron and bronze isn't as great 
according to one supplier of bronze guides. However, bronze still 
provides superior heat transfer, resists seizing and can handle closer 
tolerances (which improves valve life and reduces oil consumption). 
That's why thick wall bronze guides are preferred by many performance shops.

see the rest of their webpage for more generalized info.

Valve stem seals on the Corvair can be argued both ways, but the idea 
behind leaving them off is to improve lubrication to the lave stem as 
the horizontal layout of the valve is less inclined (get it) to induce 
oil to run down the stem from gravitational effects -- seems that either 
way is acceptable (and each has it's own proponents, as this post will 
probably demonstrate), unless the guides are badly worn, in which case 
they should be repaired rather than just sealed.

The resistance to seizing is due to dis-similar metals -- they don't use 
cast iron pistons in cast iron bores, do they?

I prefer to use the bronze guides, when it is an option.

Godspeed!

Bill Strickland