Anyone using dual valve springs in >1000 lb applications?

[blykins]

Both PAC and PSI are offering some pretty small diameter dual valve springs for ~400/~1200 lb applications. Anyone have first-hand experience with them? I'm looking at trying something different over a large triple spring.

[Racerrick]

the way it was explained to me was smaller the diameter the shorter the life due to heat build up in the spring cause there is less metal and surface area doing the same job so when you run small dia springs you need lots of oil for cooling. I would use PSI.

[carmakerevive]

+1 for using PSI

and the springs should be kept well cooled and supplied with oil regardless.

[FastBuick]

I've been running the 1.500" Dual PAC Springs for many years now. Very good springs and actually last longer than the bigger diameter springs and Triple springs. The theory behind using the smaller diameter springs is that there is less inertia with the less weight of the springs. This means there is less spring surge at high rpm and there is more control over the valve by utilizing more of the pressure to control the valve. This is because a bigger diameter spring weighing more and having more inertia actually requires more spring pressure in order to control it's own inertia.

[Jeff Lee]

I concur with FastBuick although I have not fired up the engine yet. Maybe next week? Previously had 1.625” springs and went with these that are 1.5” and while I can’t recall what the weight savings were exactly, I think it was about 1.5#’s just in springs and retainers???
Supposedly better life and better performance. Too many other changes to know but the sales pitch worked on me.

[blykins]

Anyone use them in a pulling truck application?

[Frankshaft]

Yes. I have used Pac #1357 and #1329 a number of times. They are a great set up with the tool steel retainers. They weigh virtually the same as a ti retainer, but ate way more durable. Get the nano peened as well. The most recent set went into this

WP_20170622_15_05_57_Pro.jpg

. Made a hair over 2.1/inch with the single blp 4150. Revs 9000.

[Frankshaft]

Here is how they fit

WP_20170627_17_50_30_Pro.jpg

The engine these are on, go 8200. Their 3rd season. Hanging in like champs.

[blykins]

Thank you sir.....

[fastvette]

I used the Manley Nextech springs years ago, maybe about the time they came out? Over 400 on the seat and 1200 open. Held up way better than the triples I was using. BBC 9,300 rpm.

[Brian W]

Not a high rpm deal but am using the Manley Nextech 221456 on blown alky BBC. 410 seat 1100ish open. Have worked great so far.

[hoodeng]

PSI made dual interference springs that we used in Pro Stock bike some years back now that were 400lb on the seat and over 1000 at lift ,they were 1.660"od .865"id 400lb@2.220" 1000lb @ 1.330" CB @ 1.140" [these figures are from an retired spring i just tested ,not a new one ] .The engine they were in was a pushrod 80 cu in/cylinder, had 2.700"x .312" inlet and 2.000" ex valves ,shift points were in the 9,200 to 9,500 rpm range and top limiter set to 10,000 ,if the rider missed the point we would be changing springs for sure between rounds!

Cheers.