JaredW

Putting together everything for my cam swap here next month! I am going BTR Stage 3, when I did my heads last year I used PSI 1511ML springs to keep the valvetrain as light as I could, So my question is can I use those springs or do I need to swap them out for the .660 BTR Duals?

They only have like 1,000 miles on them if that since I did the heads...

redbird555

I personally would not. Here's why, in order to control that cam you're going to need every bit of the 130 seat pressure the psi spring offers when installed at 1.800. Now that cam has .652" lift On the high side so....

1.800-.650-.050=1.1"

What I did there was take your installed height and subtract the max lift as well as .050. .050 is the margin you must leave between your max lift of the cam and the spring coil bind height. You'll notice that height is 1.1 which is coincidently exactly what coil bind height on the psi spring is.

So in theory you would be ok but it's VERY close. But more so is that most likely to control that cam you would need extra seat pressure which would require shimming the spring in which case you would have coil bind.

So in essence not it's not going to work. I'd either look at the btr dual kit or a PAC 12xx kit which would be rated at .675 or .700 which I'd feel more safe with on that cam anyway.

The other option is to go with a cam that has less lift

redbird555

It would be either of these options for me personally. The PAC is a great spring and the brand is what Mamo often specs with his builds. It also offers .700 lift capability in case you need to shim or just want a little extra room.

What lifter will you be going with?

https://www.briantooleyracing.com/pa...pring-kit.html

https://www.briantooleyracing.com/68...ls7-sk702.html

Unreal

I would run what BTR suggest.

JaredW

Looks like I'll be buying some new springs then, I don't want to cut it that close.

When I did the heads I bought new lifters so I planned to just use them.

redbird555

Are the stock lifters or did you upgrade to something better

JaredW

Just new LS7 lifters.

Da Z06

Look at PSI LS1515ML Behive, installs at 1.950", 140lb on the seat, 405lb open.

Top it with the new BTR Titanium retainer for the LS7 and wamb!

I ran that spring with .661 lift to 7300RPMs and Ferrea F2042P hollow stems on the exhaust.

redbird555

this is a great option but lots of people especially if the car will be driven a lot like the safety aspect of duals. But if the op is ok with that then this is a great option

also the ls7 lifter typically doesn't like the seat pressure these springs provide. Sure lots are ok but some start to bleed down as time passes. If you barely drive the car I wouldn't worry. But I killed a stock lifter set in about 25k miles on my last cammed car.

phipp85

Which lifter did you switch to? What is the go to hydraulic lifter that will handle some high rpm abuse(7500rpm)?

JaredW

I had looked at the 1515ML previously, but I think that since I have to get new ones anyway I am going to go to a dual, just cheap insurance and peace of mind!

I almost bought a set of Morel's instead of new LS7's but had heard mixed reviews on them. I get a car from work so I dont drive it that much. Did you go to a link bar setup?

Da Z06

If you are looking to 7500RPMs, the Behive stability is hard to beat. Harmonics, and installation problems break any spring.

The COPO LS7 runs a PSI Behive spring, stock valves and Johnson 2110 lifters to 8000RPMs and not to mention, stock pushrods.

The LS1515ML so far has proven flawless on my application, even with the 85g Ferrea HS and .661 lift.

The reason I'm swapping is that Im going with a larger cam, and I'm moving my peak HP RPM up to ~7-7100RPMs and even then, I'm going with a Behive, PSI LS1516ML (150 seat, 420lb), and Johnson 2110 lifters with stock HS exhaust valve (lighter).

JaredW

I dont think I'll need to spin that high with that cam, Maybe just over 7k at best. And I'm still on stock valves, New ones but still stock..

Da Z06

The most important thing is to do your research and purchase/install what gives you piece of mind.

redbird555

I agree with the above the Johnson 2110 or 2110R is a great lifter choice. And as said the psi beehives mentioned would be great with that build. Just comes down to the fact if you're ok with a beehive or would rather have a dual for safety.

on the lifters again though it's a tough pill to swallow because by the time you pay for 2110s the 2116 which is a shorter travel link bar lifter is only another 130 bucks lol it's a slippery slope

the 2110 lifter has stock plunger travel which means that there is a larger void where oil is filling up inside the lifter. This gives a larger preload window on the pushrods side but sacrifices high rpm stability. The 2110r cuts that plunger travel down from .200 to .150 moving up stability slightly. the 2116 is a link bar with different internals and has a .093 travel if I recall. both of those things equate to an extremely stable lifter setup.

now again that's overkill for a cam only ls7 the 2110 is fine and does the job but for the extra 130 bucks I. Pulsar turn down the 2116 for all it offers

MyLS1Hauls

I'd run what Brian suggests (that will be his BTR Platinums). He'd done extensive testing, and knows what works and what doesn't. I like PAC springs, but his Platinums have proven themselves over time. I can't argue with their long term durability.

As for the "safety" aspect of duals...I think it is a bit overstated. You can still end up with piston to valve contact if one of the coils in a dual setup fails. When one coil breaks, you no longer have enough spring pressure to control the valve. Choose your springs based on the open and closed loads required for your cam. I like to go single beehive when they will fit the requirements, but am currently running PAC duals shimmed to 150# seat load.

redbird555

nothing wrong with hi platinums at all I've ran them too but with that cam you're approaching the limit of their lift. I'd like to have some margin.

and yes you certainly can but I don't think it's over stated. But not all failures happen at high rpm and even having one small spring holding the valve up is better than not having one ata all

JaredW

Is the 170lbs of seat pressure on the high side of what i'd want for those .685's? The Pac 1207's only seat at 155lbs.

Won't the higher seat pressure be harder on the valvetrain over time? Or am I incorrect in that thinking??

Da Z06

Jared,

For that cam Ill either run the BTR .660s duals or for even more control the PSI 1515ML behive with Ti-retainers.

The 1207 is a .700 spring with a coil bind clearance of 1.000" and a recommended install height of 1.800" @ .700 lift - leaving you with .100" of coil clearance (when utilizing a .700 lift), which in most people its more than the (according to some) much more desirable coil clearance range of .080-.060".

Based on my calculations IF you decide on the 1207x, consider installing it at 1.732" (which is quite of bit of shims) for a .080" coil clearance (I personally prefer a min of .070 and absolute max of .050")

Coil Bind Height: 1.000
Valve Lift: 0.652
Coil Bind Clearance: 0.080
Recommended Install Height: 1.732

If installed with a height of 1.80" as per PAC then you are looking at:

Coil Bind Height: 1.000
Valve Lift: 0.652
Recommended Install Height: 1.800
Coil Bind Clearance: 0.148

My .02

Da Z06

.....also, another thing to note is that taking the example with the 1207x, that by installing at a shorter height you effectively increased the seat pressure from the 155lb @ 1.800" by 29.4lb = 184.4lb @ seat!

Spring Rate lb/in: 433.00
Install Height: 1.800
Recommended Install Height: 1.732
Spring Rate lb/in Gain/Loss: +29.444
Seat Rate lbs: 155.00
New Seat Rate lbs: 184.4

Hope that helps!