Good video.  What was the resolution to the interference with the stem seals?   Do you have a part number for those Subaru seals?  

The new springs I have are C-AEA526 (MiniSpares Springs).  Apparently the inner spring retainer is not needed with these because they are a slight interference fit & friction dampened.  Hopefully I won't too need the 527 springs and longer valves, but I will know soon.

Those are the very standard pressed rockers, more like 1.25 to 1.3 to 1 ratio.   You'll want to use an "anti bind' coil spring with 1.5 rockers, or at least verify you have room to open the valve without running into binding, which will at least destroy your pushrods if not the cam itself.

I made this video discussing the issues I had to overcome with a Sprite race engine I built over the Summer.  I ended up sourcing some special longer Valves from Longman in England, such that I could get seat pressure around 90 and over the nose at just over 220 lbs using the C-AEA527 'anti-bind springs with an installed height around 1.45".   The best I could do with standard length valves resulted in spring heights of around 1.35, and the aforementioned over the moon over the nose pressures... over 400 lbs with 1.5 rockers!!

Thanks for the ideas (known height spacer or rocker shaft springs).  That will at least give me room to get the depth rod on my calipers down in the pocket.  The tool pictured (bottom picture) is an over the nose pressure tester.  I don't have a standalone spring tester, but over the nose and playing with shims will give real world readings and ability to adjust shims to dial all 8 in.

New springs are dual high lift, and resting spring height from recollection is just under 1.5".  I'll have to check the page that came with them to confirm.  Valve seat spring pressure is also called out on that page, so both or either can be used to set them up.

The last set of springs were dual springs, but they were notably taller free standing on the bench next to the new high lift ones, and spring pitch was shallower.  I'm replacing the old ones because one of them broke, and coils came very close to touching on full lift.  Rockers are 1.5 rollers, and cam is a Kent 276.  The head is from my old S motor which had an Elgin cam (pin drive) of similar grind.  The new S motor has the Kent cam (slot drive), and the new high lift springs, which will be better as far as coil spacing on lift.

Existing rockers I plan to use are the MiniSport 1.5:1 rollers.

These pressed rockers came with the new engine on a different head.  Any idea if these are standard ratio or?

Head is a ported 12G1316 re-seated for Cooper S intake and exhaust valves.

I've used a tooth pick to get pretty close!  I found you could assemble the valve using one of the rocker shaft spacer springs easily by hand and get all sorts of useful measurements!   What head and springs are you using?  I found most spring pockets are too shallow to achieve the installed height specs for performance springs.  This results in some absurdly high "over the nose" numbers, insanely high if using 1.5 rocker arms!

Also check clearance for overall valve lift with your proper arms.  we've had lots of trouble lately with 1.5 arms allowing coil bind with the standard dual valve springs, or the bottom of the spring retainer to "take out" the valve stem seal.  You end up finding those tiny springs inside your valve cover.   I would think both of these problems are much more likely with shallow pockets.

Drop in a know-height spacer into the pocket and then measure either with your tool-thingie or use calipers.

If you are going through that much effort, make sure you use a spring tester to confirm spring seat pressures and over-the-nose pressures. Also, decide which readings are are more important to you.

Mix and match spring install heights to specific springs in specific pockets to optimize spring balance if you are up for that.

I started payiing a lot more attention to the spring setups on the LeMons motors after suffering a few dropped valves likely due to valve float. Since spending a few days on each head refresh, I've not suffered the same calamity as I did the first 1-2 years.

Does anyone know if anyone makes one of these valve spring height micrometers small enough to work with a Mini head?  My spring pockets are too deep and I need to measure spring height loaded (valve fully seated) so I know the shim thickness needed under each spring.  I have a Proform micrometer, but the diameter is too large to fit in the pocket or clear the rocker shaft pedestals.  

I could also add shims and measure the valve seat pressures with the tool below, but the micrometer takes out the guess work, and need to remove the spring and reinstall 2 or more times.

What other methods has anyone used to set proper valve seat spring pressure?

Thanks