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Discussion Starter #1
Hi All,

Anyone know what the effects are of installing the valve springs on an 893 upside down?

Only after rebuilding did I notice that manual says the tight wound section of the spring should be at the bottom. Im not sure I installed them any particular way up!


Realy can't imagine a huge issue - its a spring! perhaps effects on guide wear?

:idunno:
 

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I'm gonna just make a huge guess and say it will/may effect the rate as to which the spring tension is initially introduced against the cam, and afterward to the valve. And then when the valve is closing the rate at which it does will probably be off. Like I said, it's a guess. But I would imagine it will be most detrimental at a high rpm, when valve float could happen. When you look at the spring, the tighter wound portion will be much stiffer, so imagine that the weaker end is supposed to be where the stronger end is. Something is going to be off, exactly what that is I can't tell you. :think:
 

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If it has progressive springs like it sounds i would imagine putting them wrong way could cause coil bind much sooner then the other way. What does the spring look like?
 

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They are double springs, each with tighter coils at one end.
Then it just depends on how much tighter the coils are from the end and how far are they from coil bind at stock installed height. But with progressive springs seat pressures will by way of at every lift when installing them wrong way. I wouldn't risk it and possibly float and drop a valve. It looks very possible to me.
 

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From a physical standpoint, it won't effect the operation of the spring, however... The tighter portion of the spring compresses to the point of binding first. That is normal for that type of spring. If it's at the top of the valve near the seat, there is essentially more coils of spring and weight that the valve has to move to close and at high RPM will cause valve float because of the extra mass. So unless the engine will never see redline in it's life, I'd switch them around the proper way.
 

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There may be a slight difference. I'm guessing the tighter coils have less spring pressure so they are at the top near the retainer. They can be slightly lighter because they don't have to move the weight of the coils beneath them. You should check with a tech Service rep from the spring supplier.
 

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Discussion Starter #8
Thanks guys, all good points.

I'm not saying I definitely fitted them the wrong way up, just that I can't remember thinking about the way I fitted them, more 'oh look all the paint is at the bottom' (I think that's to do with weight?)

I will be sooo pissed if I strip her and find I have fitted them right way up! Winter project!

Does the head have to come off? I remember seeing a long time ago a way of pressurising the cylinder via compressed air. I guess compressing the spring to remove the collet is the issue.
 
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