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I thing so. Remember, the valve springs must have sufficient spring rate to prevent valve float at 10k revs. This increases preasure on all the things that will be involved in pressing the valves open.

just a quick question would running 10k springs on a decent street build up wear out cams valves or brake rockers quicker than stock gx valve springs. Even if you wernt reving it any were near the 10 k range?

One thing not mentioned here; people revving their A series race engines to 9800 RPM's are rebuilding around the 6 hour mark (rings bearings etc) That is about every 2 race weekends.........on the street you wouldn't be above 5500 all the time but if a motor like this went more then 1000 miles of street use I'd be surprised. Also not mentioned stock gearbox drops 2800 RPM's between 2nd and 3rd...........so the motor which will be kinda lumpy below 5500 won't be much fun.

Tom

Awesome vid on floating the valves,
The double springs are also to reduce the harmonics in the spring, in a suspension spring you have a shockie to dampen the spring, no such luck in the valves,

I have been supplying a few people with double springs, both GX type and 10k rpm style, with retainers and seats and a set of collets...

Back on topic.

Go turbo. Alot cheaper then your monster A15. Im planning on doing a simple suckthru turbo setup, at the moment i can see it coming in at easily under $1000. 120rwhp mark on 10psi???

What car is the A15 in? Remember weight plays a role. I can see my stock A15 in my 1000 wag beating V6's. Depends on driver and gear ratios too.

Then with all this power you will need to upgrade brakes/gearbox/diff etc.

Seeing as your in perth, come along to the next datto meeting and meet some of the boys and ask some questions. Some of us know what we're talking about

And 13206-D0200 -seat-valve spring- inner

I use Holden ones

And I don't tev the tits off my car

7500 rpm changes on the track

Factory GX part numbers are obsolete and NLA.
I know a bloke who's dad has an ex shellsport B310 coupe racecar. His engine pulls to 9K. BUT, it has some BIG dollar bits inside it. And, it's subject to regular pull downs.

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

The Nissan Bluebird U11 have double valve springs.
I don