When Valves Don't Measure Up Part 2

[vairmech]

I have some pictures of some different brand of valves and I have the same issue. I think I stated before that I reset the collar on my tool and I also recalibrated it. It is within .001" on average, close enough for spring work.
So with that I was putting together another set of heads and different valves. What do I come up with? Small shim numbers or less than the thinnest shim of .015". With this first picture I am showing the different retainers that I have in the batch I had out. As you can see there are at least 4 different styles on the spring side.



Then look closely at the details on the top side, again 4 different styles.



So now I get into the measuring of the spring height, this picture is of my first measurement. Keeping with the 1.7" spring height there would be no room for any shim. Remember the thinnest is .015 and this is showing 1.702". There is no such thing as a .002" shim!



Now I try a stock valve in one that I had already measured with the new valve. If you look at the number I got a huge jump in numbers! I used the same keepers and retainer, just a stock GM valve! If you read the number on the head that was my first measurement. Just changing the valve I got a .022" change!!!



This issue was mostly with the exhaust valves for this set, the intake valves were long enough that I had to use
.030" +- shims. But when it came to the last valve or two I still had to cut the face and almost to the minimum margin to be able to get a decent shim.
Here are a couple of pics of the valve and a stock valve.




BTW, I put the stock valve in and I had plenty of room to put a .030 something shim in as you saw above. When I did all of these comparison checks I used the same retainer and keepers unless I was mixing and matching for clearance. You can see the mix and match between these 2 pics. Look closely at the differences, the keepers set farther in the retainer and the retainer has a sort of dimple in it..




Lastly this is not something you see everyday and I really wasn't looking for this and had I used this what could happen? Even if the keeper did break the parts are captured and couldn't go anywhere. No, I didn't use it!

[joelsplace]

I've pulled heads apart where the grooves in the valve for the keeper were almost worn through. Is that common? That would make the valve spring installed height keep getting bigger until it dropped.

[chris]

I've pulled heads apart where the grooves in the valve for the keeper were almost worn through. Is that common? That would make the valve spring installed height keep getting bigger until it dropped.

Yikes! That might be a problem. Was this on valves with the multiple grooves or the single groove or both!?

[joelsplace]

Multiple grooves

[vairmech]

I've pulled heads apart where the grooves in the valve for the keeper were almost worn through. Is that common? That would make the valve spring installed height keep getting bigger until it dropped.

I have seen that but only in a few I have taken apart. Obviously the keepers and the valve get tossed. Keep in mind with the exhaust valves, all small valves, have the multi-groove valves. These valves are free to spin in the keepers! That is why they don't need the rotators.

[vairmech]

I've pulled heads apart where the grooves in the valve for the keeper were almost worn through. Is that common? That would make the valve spring installed height keep getting bigger until it dropped.

Yikes! That might be a problem. Was this on valves with the multiple grooves or the single groove or both!?

This happens mostly with the multi grooved keepers but I have seen a few where the single groove was worn some but never like the multi grooved ones.