Valve springs and shims

[Freightshaker]

Was reading and searching on springs out of curiosity. Also read the good how to write up in west point on them.
I have a couple of questions on them that I had trouble finding answers for or a little more explaining.
With 910 springs I see where some shim and some do not shim. I understand that it is used to up the seat pressure some, but also for install height.
-Can someone explain install height a little more?
-are 910s it or do other springs require machine work?
-is shimming primarily just to compensate for wear, add seat pressure

 

[smokinstroker92]

Was reading and searching on springs out of curiosity. Also read the good how to write up in west point on them.
I have a couple of questions on them that I had trouble finding answers for or a little more explaining.
With 910 springs I see where some shim and some do not shim. I understand that it is used to up the seat pressure some, but also for install height.
-Can someone explain install height a little more?
-are 910s it or do other springs require machine work?
-is shimming primarily just to compensate for wear, add seat pressure

Install height is the height of the spring from the valve seal to the top of the spring. There are other springs available but not as affordable as 910s. 910s will be fine for 90% of people unless you need much higher seat pressures.
Shimming does compensate for wear and achieves the seat pressure that you are looking for. The springs have a spring rate at which the pressure increases as the spring is compressed, and a given seat pressure at a certain installed height. This means to find the seat pressure at a given install height you take the given seat pressure and use the spring rate to calculate the seat pressure at your given install height. You also have to consider the height which will cause coil bind which is given in the spring specs as well. Factor in the valve lift which i believe is .450in if i remember correctly.

 

[littleredstroker]

The valve spring micrometer I bought wouldn't fit over the valve seal. I took valve seal out, put it all back to together and measured the height , then subtracted the thickness of seal, less 1.750 and that's what I used to shim. I only had .030 and 0.15 so I just got it close as I could

 

[Freightshaker]

Appreciate the input fellas

 

[Lang]

Install height is the height of the spring from the valve seal to the top of the spring. There are other springs available but not as affordable as 910s. 910s will be fine for 90% of people unless you need much higher seat pressures.

Shimming does compensate for wear and achieves the seat pressure that you are looking for. The springs have a spring rate at which the pressure increases as the spring is compressed, and a given seat pressure at a certain installed height. This means to find the seat pressure at a given install height you take the given seat pressure and use the spring rate to calculate the seat pressure at your given install height. You also have to consider the height which will cause coil bind which is given in the spring specs as well. Factor in the valve lift which i believe is .450in if i remember correctly.

Does anyone of a pic of how to measure them? I'm capable of doing this myself just never have. Trying to figure out how to exactly.

 

[Freightshaker]

There was a pic in the 910 write up in west point but I was unable to view the picture.

 

[hwrdbd]

If you get a valve spring mic tool from somewhere like jegs, they're around 60 bucks. I borrowed one from my friend. The tool is basically a cylinder that reads measurement as you unscrew it, thus extending it. Install it in place of the valve spring to take your measurement, then remove it, add shims and put the spring in.

 

[Lang]

If you get a valve spring mic tool from somewhere like jegs, they're around 60 bucks. I borrowed one from my friend. The tool is basically a cylinder that reads measurement as you unscrew it, thus extending it. Install it in place of the valve spring to take your measurement, then remove it, add shims and put the spring in.

Making more sense. Just thought there was 2 different ways of measuring spring height?