Valve Springs

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01-07-2019, 06:40 PM

AP1Jonathan

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Valve Springs

I have a bag of AP1 valve springs that I got from a friend. They have been washed so that there’s no paint (yellow or blue). I have no idea how to tell which ones are intake or which ones are exhaust. I know they’re two different part numbers but could they be interchangable without problems? Or is there a way to tell them apart without the paint? Thanks.

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01-08-2019, 05:44 AM

windhund116

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Know anyone with valve spring pressure gauge?

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01-08-2019, 10:22 AM

Chuck S

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When new the exhaust valves have a slightly longer free length. May or now hold true once they're been in service under heat.

Source: S2000 Service Manual (2000 to 2008) Page 2-3:

The spring rates for the OE valves are not listed, just the free length of new springs:

AP1 (00-03) intake: 49.77mm
AP2 (04-08) intake: 49.76mm

All (00-08) exhaust: 50.39mm

The service manual is specific about placing each spring back on the exact same valve it same off of. Don't mix them up. Seems that's been done.