What height should valve springs be installed?
What height should valve springs be installed?
0.020″
An installed height of +/- 0.020″ is acceptable. If the installed height is not within 0.020″, either machining of the valve pocket, or removal/installation of valve spring shims is necessary.
What is valve stem height?
Stem heights are increased when the valve seat is ground and when the face of the valve is surfaced. As this puts the tip of the valve stem higher in the head. This will also effect the valve spring installed height, but more on that in another article.
Which way do valve springs go in?
You are in fact correct, the tighter end goes on the head and the looser end goes to the retainer.
What is valve stem necking?
Check valve stem installed height any time the valves or seats have been replaced or machined. Valves become stretched at the neck just above the fillet. This stretching is known as stem necking. It’s the result of hot exhaust gases swirling around the neck.
How tall does a valve stem need to be?
All valve stem heights must be within specification. If one valve stem is higher than the others, suspect that the valve face or seat is worn. A valve stem height gauge may be required to measure this height. The seal between a valve and its seat must be very tight.
How are valve stem installed and valve spring installed different?
It’s the result of hot exhaust gases swirling around the neck. Valve stem installed height is different than valve spring installed height. Valve spring installed height is taken from the underside of the valve spring retainer/rotator to the valve spring seat.
Where do you find the valve spring height?
It is measured from where the spring meets the bottom of the retainer to where it rests against the cylinder head. All camshafts come with a recommended valve spring height; it is usually on the spec card included with the cam.
How do you measure the height of a valve?
DO NOT INCLUDE THE THICKNESS OF THE SHIMS. Use a valve spring height micrometer. Much more precise than a ruler, the micrometer replaces the spring itself. All you have to do is turn the dial until the valve is seated snugly in its seat, then note the measurement.
All valve stem heights must be within specification. If one valve stem is higher than the others, suspect that the valve face or seat is worn. A valve stem height gauge may be required to measure this height. The seal between a valve and its seat must be very tight.
It’s the result of hot exhaust gases swirling around the neck. Valve stem installed height is different than valve spring installed height. Valve spring installed height is taken from the underside of the valve spring retainer/rotator to the valve spring seat.
Do you have to Shim a valve spring?
If the spring is not at the recommended installed height, you will either have to shim it until it reaches the proper height, or you can machine the spring pocket in the head deeper to get the installed height you need.
DO NOT INCLUDE THE THICKNESS OF THE SHIMS. Use a valve spring height micrometer. Much more precise than a ruler, the micrometer replaces the spring itself. All you have to do is turn the dial until the valve is seated snugly in its seat, then note the measurement.
