How to test Valve springs
 

How Valve springs are checked


I had to check the valve springs for a 4G63T


This is a simple process. But a specialized piece of equipment is needed.

I use a Rimac spring tester with a 300lbs scale.

The first thing to do is set the stop to the correct height.
The spec used is 66lbs @ 1.575
I find that a venier caliper is more accurate than the built in scale.
https://www.miataturbo.net/attachmen...ine=1332518366

Place the spring to be tested in the spring tester

https://www.miataturbo.net/attachmen...ine=1332518366


Compress the spring to the pre set height and read the pressure.

https://www.miataturbo.net/attachmen...ine=1332518366

It is a quick and simple way to have your valve springs checked to make sure they are in good serviceable shape.

Low spring tensions can lead to a lazy rev of your engine and also valve float.

Most of the valve springs I tested I found to be well out of a usable spec.
Most springs I tested fell in the range of 40-55lbs @1.575
Most spring manufactures allow for 10% loss of spring pressure for spring break in.