Valve spring measurements

[jrvariel48]

I took a bunch of measurement on valve springs today & I'm coming up with a lot of different numbers. What am I doing wrong? Should they all be the same?

 

[40cpe]

I don't think that is unusual. The free length is less important than the pressures at installed height.

 

[Ol' Ron]

installed height of 50 lbs is what your looking for.

 

[v8fordman]

Anyone know what the installed height is for the different types of valve assemblies?

 

[flatjack9]

The installed height is determined by the spring pressure you desire. If you want 50 lb on the seat, you measure the length of the spring that gives you that pressure. The valve assembly is then installed and the spring is adjusted to that height. Care must be taken not to get in a spring bind condition.

 

[Karl Wolf]

As a quick and dirty check, I put the springs on a flat surface close together. Look to see if they all are at the same height on top. If not, I would suspect that they're due for replacement.

Karl

 

[flatheadmurre]

As a quick and dirty check, I put the springs on a flat surface close together. Look to see if they all are at the same height on top. If not, I would suspect that they're due for replacement.

Karl

That doesn´t say much about the pressure installed....they can be perfectly equal but tired and give you a low pressure installed.

Some kind of a scale in the drillpress and a caliper to measure so you can get a reading at your installed heaight is a better way to do it.

 

[51 MERC-CT]

As I understand it.

 

[jrvariel48]

As I understand it.

That is an excellent diagram!

 

[Ol' Ron]

Yes, wish I drew it. Now everybody copy it. I use 50lbs on all street cams except the 400jy which requires more. This includs the L-100. Works great up to 5K

 

[Bolts]

To the original posters statement about valve spring length. I bought a used set of 8BA valves, springs and retainers from a guy that said they came out of a running flathead V8. I believe him, but the springs are short.
Comparing them to the 59AB springs I took out of the old engine I'm working on, the springs I got from the guy are about 1/2 inch shorter. A crude seat pressure test I made shows a compressed spring force on the short springs of about 25-30 pounds. The old 59AB springs are reading about 55 pounds.
I don't intend to use the short springs, but I'm wondering two things:
1) Will a stock flattie run with 25 pounds spring seat pressure and
2) Has anyone ever seen springs like these in a Ford flathead engine?

 

[flatheadmurre]

They are probably for use with the valve rotator setup on later engines.

 

[JSeery]

As you stated, you are comparing 8ba springs to 59ab springs. As flatheadmurre stated, most likely the 8ba springs were used with rotators.

 

[Ol' Ron]

Yes, the springs came from the late 51 to 53 engines with valve rotators. I install a .060" spring to use them on the Max #1 cam. Works great.

 

[GOSFAST]

I took a bunch of measurement on valve springs today & I'm coming up with a lot of different numbers. What am I doing wrong? Should they all be the same?

As I understand it.

The picture directly above (51 Merc) here is good but it should also include the block with the valve sitting directly on the seat?

I'm not sure about Joe's picture above with the spring and the Vernier, but you can't check any installed hgts w/o the block in play!

We just finished setting up some springs with our "new" spring-locators, the photo below shows that 11 valves required a total of .180" shims to get the pressure correct, about 5 needed .150" total.

The locator's themselves are .060" thick, the necessary shims sit below the locators. We can fit as many as 5 shims PLUS the locator's on the guides using stem seals. That's a total of almost .375" (if this were necessary) to get to the pressure needed.

Thanks, Gary in N.Y.

P.S. Here's a couple shots of the finished products, the way these particular spring's are set up they will yield 55# closed, open pressure depends on the cam lift! At about .350" lift these will be about 100/110# open.