OST-053: Massaging a 20V Blacktop

[oldeskewltoy]

(08-14-2019 04:25 PM)Project D Wrote:  .0105" / .0175" within .005" so .26mm / .44mm within .13mm
I never realized how BIG the valve clearance where on the 20v !

If I may ask, why did you choose the Toyota specs (.015" to .020") over the Kelford specs (.30mm so .012") on the exhaust side ?
Or maybe it's a typo on the Kelford spec card ?

Quote:I'll wait.....

You found what I was alluding too.......thank you. Toyota has a minimum spec, it is based on a great deal of engineering, and KNOWING the materials that they build the engines with. There is a LOT of expansion on the 20V exhaust valve. Besides Toyota's spec, I've been told by a Uk 4AG engine builder that as well. The Uk engine builder advised me in the past to avoid over ambitious (tight) valve clearances on the 20V valves, especially on the exhaust side.