Hi,

I am looking for info as to why the clearence is so large on the most water cooled motors. I now have a 78 LeBaron with a /6 225 motor. Many of my previous cars have been air cooled VW's with valve clearence set to .006 - .008 for both intake and exaust. This is set cold and I never had a burned valve.

Thank you

Paul Bodmer

raven@empire.net

I think it's a little like comparing apples and oranges. In a VW you have an alloy block, cast iron cylinders, alloy heads, and small valves. In an average slant you have a cast iron block(with integral cylinders) and head and really long push rods.
I believe the amount of thermal expansion is dependant upon the change of temperature, the coefficient of expansion of the material, and the size of the material sample.
I don't have my Machinery's Handbook on me right now, but I am pretty sure cast iron 'grows' alot less than aluminum/ magnesium alloy for the same temperature change.
My guess is that when the VW is warming to operating temperature everything alloy grows at such a rate that the (relatively small)cold setting clearances remain adequate even when the engine is hot. What are the clearances when hot?

fglmopar@aol.com