Are my valve springs too long?

Before rebuilding my head I decided to measure the springs - they were all between 1.5 & 3mm shorter than the spec. But my new ones just arrived and they are all 2.5 - 3mm longer than spec (inner 40mm outer 44mm). Should I just go ahead and use them?

Second question - what is the significance of the red paint on the inner springs?

The original spring is on the right in both picures:







Thanks for any advice.

Who was your source for these springs ?

"British Only" supplier in Austria

They mark springs with paint to ID them. For something as important as valve springs, I would get OEM type Norton springs from Andover Norton. They are good springs to use. And have proper spring pressure rates. At least the ones I got a few years ago, I just measured Brand new AN ones, Outer = approx 42.3 inner 38.5

They may be longer, but the spring pressure could be the same since the wire looks thinner on both the inner and outer. What I would check for is spring bind when compressed to whatever lift your cam is capable of making. There are videos on the internet that describe how to check for valve spring bind. JS Motorsports might have a video for checking bind. He uses different beehive springs, but the principle is the same. If really worried about it, you could remove the insulator under the valve spring seat (if your head has them), but then you might not have enough spring pressure. Or just get the AN springs as mentioned and skip all the checking and workarounds.

They have one more turn and are wound the opposite hand. The extra turn means with the same wire thickness they are weaker, think of a spring when you unwind it to a long straight rod and the longer the rod the weaker it is. Get the proper springs from AN, from their pics they have the right number of turns.

Last time I played around with "uprated" valve springs on a Norton, I snapped a rocker arm. All around bad day. I agree with the experts, why take the chance, get a set of springs you know are correctly rated.

Norman White used standard AN valve springs in race engines with PW3 cams, no need to use anything else unless you want to go with single spring beehives!