Hello! Have some issues here I’m trying to clear up and I feel like my questions aren’t being answered correctly or I’m miss understanding something.

Normally I run the btr .660 kits, ran tons of them with no issue. My new build has a large 253/261 .651/.650 cam and I thought I had better step up the valve springs. So the search began, and I ended up on the BTR .685 lift titanium kit, roughly $60-80 more than the .650 kit. Great! Advertised as a stout spring made for high rpm operation. Perfect, just what I need. Bought them!

Springs show up a week or so Later, yesssss. Time to go to work. Open them up and notice the springs came with 2 sets of shims. Hmm, after buying 20+ kits this is the first time I’ve ever got shims with for free.

Then I notice the box says .650 lift kit. ****.! They sent me the wrong springs. Call them up to return them and they tell me the .650 lift springs are the same kit as the .685 lift springs, you just don’t use the .035 worth of shims that come with them to get the extra .035 worth of coil bind space. I’ve got this answer multiple times now.

Hmm, that doesn’t seem right. How can these springs be for more aggressive camshafts yet you are losing a bunch of spring pressure by not running the shims. That doesn’t make sense to me? How can you use less shims with the same everything else and the spring supposed to handle a bigger more aggressive camshaft? So I look on the website, and the confusion gets worse.

At 1.8 the springs without shims are advertised to have 170# if pressure.

at 1.8 the springs with .035 worth of shims are advertised to have 150# of pressure.

How can this be? AND WHY DOES THE KIT THAT IS IDENTICAL COST $60-80 more?!?

This is going on a brand new 14:1 ls1 build I plan on spinning 7500+, so I’m really concerned about all of this.

 

Some verbal information is wrong somewhere... screen shot info and specs make sense. Something got said or taken wrong about the shims.

Going just by the screen shots the 685 kit actually shows to have coil bind at 1.0 and the 650's at 1.1, that means the spring is shimmed more on the 685 kit (it coil binds sooner) which would be what you would assume would be the case to get a 650 spring to be rated for 685. So that checks out.

In the descriptions you posted the 650 set says 15 (not 150) at 1.8 and the 685 170 at 1.8. I assume they meant 150 at 1.8 for the 650 kit.. so going off that the 650 kit would be 150 at 1.8 and the 685 would be 170 at 1.8 which checks out to the 650 being not shimmed and the 685 a shimmed 650 kit

The 650 says 420 at 1.2 and the 685 set says 450 at 1.1, that also checks out and would indicate that the 685 kit is shimmed and 650 is not

Everything seems about right/logical except for what you said you were told... maybe try to get someone else on the phone?

 

The .650 kit uses the shims, the 685 kit does not, that’s how they gain the extra lift. How can the same spring, retainer, and locator combo have less spring pressure with more shims, as it states?

 

Nothing is gaining "extra lift". And you don't need any extra either. Both set ups go into coil bind at or over 1" and you're only at .650 which is barely more than half of that, you don't need "extra lift". You need to gain spring pressure to control the valves with a really big cam. To increase spring pressure you add shims (unless you go to a stiffer spring but in this case you said it's the same set of springs)


It wouldn't have more pressure with less shims. And it doesn't state that. I don't see that written anywhere in the product info
I get that you're saying someone told you that, but that sounds backwards to me thats why I said try to get someone else on the phone.


And the pressures are listed higher on the 685 set which means it's shimmed. I typed that all out already. The screen shots are giving higher pressures to the 685 set which indicates a shimmed spring.

Try reading it again.

I posted that the 650 set shows 420 pounds at 1.2" and the 685 setup shows 450 at 1.115 THAT MEANS THE 685 SET HAS MORE PRESSURE AT LOWER LIFT and if the springs are the same then that means the 685 is shimmed

Also it shows the 650 goes into coil bind at 1.10" and the 685 goes into coil bind at 1.00" IF THEY ARE THE SAME SPRINGS then that means the 685 set is shimmed. Think about it.

Someone told you backwards it sounds like

 

Try actually reading my posts carefully and taking the time to understand that what I'm telling you is that your suspicions are likely correct and what you say you were told sounds backwards. None of it makes any sense. And the seat pressures at certain lifts prove it. But you've got some of the numbers mixed up in your original post. You're saying the numbers are higher at certain lifts for one set vs the other and you have that backwards. The numbers are higher on the 685 set and you keep saying they are lower.

 

What is your valve lift?

 

.651 intake and .650 exhaust

 

not enough spring for 7500+ anyway

 

I’ve had fantastic results with pac 1208x up to 8000 rpm FWIW

 

And what lifters? That’s plenty of pressure if you have lifters that won’t pump up and go crazy with rpm.

Now the .685 kit with the installed and cb height won't get to .685... They're good to .650. There is a typo somewhere in the info.

 

There is a lot wrong with what you are saying. First, coil bind is the height of the spring at which the coils touch. They can't be the same spring with different coil bind heights. Coil bind has nothing to do with the amount of shims used. Installed height does. If you have a 1.8" distance between the spring pocket and the retainer, that's the installed height. Now add 0.030 of shims, your new installed height is 1.770. Not 1.8". Therefore, you can't have two different pressures at the same installed height for the same spring. These are two different springs, someone is wrong here. At least as they are advertised.

What you CAN do is take them to a machine shop, or buy one of the spring testers. Check the pressure at the installed height and go from there. You will know for sure what springs you have and then you can return them or shim them to what you need. With the .685 springs, you can shim them quite a bit and pick up another 35-40lbs on the seat at least.

Hammer jammers 1208x is an excellent spring. The LS 1513ML for PSI might also be a great option.

 

I agree with hammer. Return the kit if it is not what you want. 1208x or 1209x are excellent. Also check out Manley nextek.

 

Given the confusion with the BTR springs, I'd return them as well and get something else like the others mentioned.

 

Cookie cutter parts are for cookie cutter builds

 

The btr .660 platinum kit has also been good to me. Shifting as high as 7600rpm with .615 lift. But don't think i'd trust them enough for any higher rpm, not enough pressure imo.

If their .685 kit isn't a stronger spring, i would get something else as suggested. You don't want to be saving money on valve springs.

 

This is getting a little crazy. Neither set up is in danger of binding at 650. What you have to determine is how much spring pressure is needed to control the valves at 7500 and if the lifters are upto it. The taller installed spring will have less seat pressure because it is under less compression. When I say taller, I mean installed spring height and not overall. Similarly, springs require more pressure to compress as they shorten. So, the shimmed spring requires more pressure at the same lift.

Also, I haven't used PAC 1208x, I use Howards, but if Hammer has had good results thats something to consider. Besides, with that sort of RPM you should consider solids.

 

I know what coil bind is.
He said they were without doubt the same exact springs in both kits. If they are then adding shims in would make the spring coil bind at lower lift than without the shims. That is not incorrect. Adding shims reduces installed height and gives less room for the coil to compress before binding.
I get the whole installed height argument, though. I wasn't even venturing off into that.
But really, there's too much info missing or skewed here. That's the main point I wanted to drive home was something was dramatically wrong with the info and he needed to get someone else on the phone. Which was what I wrapped up with twice already, and now a third time.

 

I ended up ditching the BTR parts and going to the pac spring hammer suggested.

 

Not entirely true, depends on the whole setup. The BTR 660 set has seen 7800+ on multiple builds without issue.

Exactly lol Its not even that big of a cam and nobody even asked about valve weight.