If i intend to run on double valve spring, and say i have the outer stock spring only....is it possible if i fabricate the inner spring on my own. The diameter and height should not be a big problem, but how about the stiffness ( spring constant ).

**Some of u might think - why dont i just get a GX head but the reason im asking these silly questions is because i have never seen a head with double spring ( gx head ) in my country. So, i have no hope of owning one. Thanks...

You will probably find the outer spring on a twin spring setup is still lighter than the single spring
So by making a centre spring if its too heavy will give way too high seat pressure and require alot more effort to work
The idea is to use the lighter spring possible without having valve float
Too heavy and it just won't rev

Can i summarize it like this:- ??

For Single spring setup:-

-Outer spring is harder than the outer spring in a double spring setup


For Double spring setup:-

-Outer spring is softer than the outer spring in a double spring setup.
-How abt Inner spring vs outer spring?


Thanks guys...

Where would you get dual valve sprngs in the U.S.? Something suitable for the street. If they could be pulled from another engine that might make them easier to source since not many folks build these engines here.

Yeap sundat...if we can source out from a different engine, it would be great..

We need to know the recommended spring stiffness first. Anyone have info on this?

to my surprise, the l18 i've got in a sunny has twin valve springs, & i was told by someone i've know for a long time & trust, that all l series engines have them. So maybe you can use them in an A series. You'd have to measure the assembled heights & such, but it's a possibility.

do you now the factory reference for the 1200 GX double valve springs??? it

The Nissan Bluebird U11 have double valve springs.
I don

I found de factory reference for the Bluebird u11 inner springs and valve seat it