Checking Valve Guides for Wear![]() Special Tools: P 21b Valve guide plug gauge See: Replacing of valve guides see 35 EN. Clearance between valve guide bore and valve stem is: Valve guide bores should be measured with a valve guide plug gauge of 10 mm diameter (.394in). When installing the sealing caps, it should be noted that first the valve is pushed into the valve guide and then the sealing cap pulled over the valve guide until the base of the cap comes to rest against the valve guide. |