Valve Spring Compressor Adapter - PARAMETRIC

This is an adapter to turn a regular old C clamp into something like this:

You need a basic clamp that is wide enough to get around the head. I used this Irwin 8"x4" C Clamp for my single cylinder Honda head and I had plenty of space left over. It only has one opening for inserting the collets since I was worried about strength, but it's still pretty easy to use. I think it'll work for any size engine, although with big enough valves it might be easier to use the standard OHV style you can get at any auto parts shop for $10.

Parameters: 

(see photos)

Angle - The angle apposed from the clamp that you want the opening to be. Base this on where the clamp will sit when you have it installed. 

Retainer Inner Diameter - Inner diameter of the hole in the valve valve retainer that the collets go into. If there's a chamfer on the hole, go with the larger dimension.

Retainer Outer Diameter - Outer diameter of the valve retainer. Make sure to take into account any dimensional inaccuracies in your printer.

Clamp Length and Width - Dimensions of the head of your clamp.

Clamp Offset - The distance from the end of your clamp facing AWAY from the C to the outside of the screw.

Clamp Screw Diameter - Diameter of the screw side of your clamp. Only used if you need the cover.

Valve Diameter - Diameter of the valve face. If you have two valve sizes (intake+exhaust) you should be OK going with the smaller of the two.

Printing:

The included .stl is for my specific set up. It's a 1980 Honda XL250s head and the Irwin 8" clamp linked above. Should work for most 250cc engines, but you SHOULD edit the parameters for your specific situation. 

Printed in eSun recycled PLA with .6 nozzle. You don't need any fancy filaments since the stress is along the Z axis.

Print in the orientation of the included .stl. If you can bridge a gap the width of your clamp head, you don't need supports.

Recommended Slicer Settings:

Walls: 1.2mm (this leaves enough overlap to make bridging easier)
100% Infill (this might not be needed, but why take the risk? Springs are scary)
Top/Bottom Pattern: ZigZag
Top/Bottom Line Directions: [0, 90]
Supports: as needed

If you need a different file type LMK

Ignore the printed ring around the valve spring, I was using a spacer to measure the installed height.