View Full Version : Homemade Valve Spring Compressor

10-04-07, 01:37 PM
Needing to replace valve stem seals on the 96 STS engine, I found the Kent-Moore tools a bit expensive and decided to make my own jigs/tools to compress the springs to allow removal/installation of valve springs. I used mostly wood for stock, since I don't have welding tools/skills.

What I finally came up with is a pair of "siceboards" mounted on either side of a HD by brackets that sit on top of the cam cap bases. The sideboards for the Intake and Exhaust side of a HD sit at different angles relative to the top of the cam cap bases, to match the valve stem angles. See the pics showing the sideboard in use. valveCmpsrAssembly.jpg

A jig made from a 1.5x1.5 inch piece of oak with a bolt hole drilled along the axis has a bracket on one side that hooks under the sideboard and allows the jig to be slid along the sideboard to the lifter bores. A nut is embedded in the bottom of the oak piece. The bolt is used to apply pressure to the valve spring retainers through a wooden dowel that is partially hollow, and open on one side to allow finger and tool access to the top of the valve stem. See the pics of the dowell and jig with the bolt.
A nickel is embedded in the top of the wood dowel to disperst the load from the bolt as the spring is compressed. Note the use of pvc pipe that just fits around the spring and retainer in the cavity. This serves to protect the wall of the bore and position the dowel correctly on the retainer. The center if the bolt is positioned in line with the valve stem. A screwdriver handle was swedged into a deep socket that fit the compressor bolt allowing the handle to remain on the bolt after compression while the keepers are removed with a small, powerful magnet. Saves a little time.

The keepers are loose after the spring is compressed a quarter of an inch or so. Valves muct be held in place by a small block of wood if working on a bench, and by air if the HD is still on the block.

Replacing the keepers was the part that took some learning. However, it is very simple and fast. Insert the keepers into the retainer (well oiled) and place on top of the valve spring. After the dowell is placed on the retainer and a slight amount of tension is applied, use your finger tip to press down on the keepers/retainer as the spring is compressed. The keepers are forced around the valve stem (this finger pressure also centers the retainer with valve stem). As the valve stem comes up through the keepers, the keepers will drop into the notch in the stem. You can feel this action. Then release the pressure, watching the keepers to insure they are in the notch.

Should a keeper get out of place, remove them, take the retainer out and start over. Trying to use forcepts to wiggle them into place is really time conusming and frustrating.

In another post I have describe the tool I made to remove the valve stem seals and show some pics.