ok, i have here 8 comp. doble valve spring ,i think they are from a old competition datsun Z big one is 30mm x 55mm small one is 23mm x 46mm questions are : will these fit my a15 head?, if they do fit, can i use stock single spring retainers?, if i can used them in my stock a15 what will this do?

thanks. :)

here are the pictures

[URL=http://img340.imageshack.us/i/sany1149q.jpg/][IMG]http://img340.imageshack.us/img340/7665/sany1149q.jpg[/IMG][/URL]

[URL=http://img545.imageshack.us/i/sany1148u.jpg/][IMG]http://img545.imageshack.us/img545/28/sany1148u.jpg[/IMG][/URL]

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Put them on and try it.

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Seeing as you have them there you are better off checking yourself. Measure them up against the stock springs and see how they compare.

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Yes assuming the springs are of a size that will actually fit under the retainers. If they're too big in diameter you won't even get them on. And if they're too long you'll end up with them binding when the cam lifts, which means they will probably hinder performance.

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Considering they are used and untested I wouldn't expect too much of them, if the spring rate is still good and the pressures are still better than stock then all they'll do is let you rev a little bit further. But the cam will probably be the biggest limiter for revs as well as the fact that the engine hasn't been balanced to spin above it's factory determined redline.

Test their spring pressure and compare them to your current ones. But in all honesty a carb upgrade would bring more power...much more power than a spring upgrade. Otherwise do the springs and cam at the same time.

There are aftermarket holden dble valve springs
that can be used but dont know the part numbers
they are supposed to be much cheaper than others

I've always thought that the valve springs from the L series engine might be a source for the a series, but if it was that easy wouldn't somebody have used them already( L series are double valve springs). I've used the outer valve springs from a VW beetle engine with a mild street cam, if you used the full set that'd give you twin springs, & would probably be easier for you to source out of the USA than Japan or Australia. You should use the twin valve spring retainers & lower washers. They keep the 2 springs from hitting & binding, & ultimately breaking.They can be bought new from Pitroad in Japan or BProject & are small enough that the freight shouldn't be too expensive.

Itd be great if L series dble springs fit, but Im
sure they are bigger than the A series ones.