valve spring change necessary?
 

Hi again,

since my last thread about the old faithful cam was closed, I have to start a new one.

It's now clear that I will swap the XE276HR for a Butler "OF" cam with LS at 114°.
My mechanic wants to keep the old valve springs and I need to know, if this will work and be safe. I have these springs at the moment:

https://www.summitracing.com/parts/lun-73100-16

I won't go past 6000rpm.
If we need new springs, I will need a tool to change them with the engine in car and heads still in place. Not sure if this is easy to do, since we only have a tool to change springs with the heads off.

Thanks a lot for your opinion on that.
Chris

i cant confirm the springs are ok... but removing the springs while in the car is easy & can probably use the same tool you have if there is clearance, otherwise auto parts stores rent valve spring compressors that will fit with engine in the car.

all you need is one of the spark plug adapters to connect an air line to it that keep pressure on the valves so they dont drop out while changing the springs.

A Moroso spring compressor makes it a breeze!
https://www.moroso.com/stud-mount-va...mpressor62370/

Good to know which tools will do the trick. I cannot find these tools where I live, so $ 133 translates to at least $ 200 until I have it with shipping and taxes and I will only use it once (probably).

The other tool we have will not work with heads on the engine.

Would be a lot cheaper and easier to keep the Lunati valve springs...
( 135 for springs, 133 for the tool plus 70 shipping plus 25% extra = $ 422 for new valve springs)

You will want about 150 on the seats.Check to be sure.Tom

I think someone copied that tool and it is cheaper. But the time fighting springs with one of the lever types it is worth it. It locks in place when compressed.

Bar type take less room to operate. Especially needed when AC box and brake boosters are in the way.

Be easy enough to fabricate one if you have to. Think my first one started life as a lawn mower blade.

https://www.grainger.com/product/1UB...B&gclsrc=aw.ds

Clay

Those springs are for a Aluminum aftermarket head with about a 1.800"to 1.850" installed height.

Are your heads aftermarket?

New Valvespings are a real good decision for rpms over 5,000.

I rarely, if ever renewed my valvesprings.

Sorry forgot to mention.. I have 72cc E-Heads (d-port).

Most times on the track I did not rev over about 5400 since it makes not much sense. But the car is mainly steet driven (99%) and the engine will not spend too much time at very high rpms.
I just want it to be safe, if occasionally I will rev to a max of 6000.

We monitor the valve springs with a LSM brand on the head valvespring pressure checker, there are other brands but that is a good one.
Just be aware these types type of testers can vary considerably compared to a bench tester like a Rimac machine.

In all instances our LSM checker measures less with installed springs vs the springs tested prior to installation with the Rimac tester. It can be as much as 10-20 pounds less !
Therefore the on the head spring tester is used only for us to monitor the springs with use over time. I use a solid roller cam set up and we check the valve springs once a year when the lash is checked.


.

Chris, please stop being so vague and tell us which part number Cam from Butler you will be using?

Thanks in advance!

This cam: https://butlerperformance.com/i-2936...tegory:1272239

# CCA-BP8031SP

They say it's the same as this cam, but with wide lobe sep. https://www.summitracing.com/parts/c...1/make/pontiac

engine is a 462cui, 1.5 roller rockers, 72cc edelbrock d-port heads, rpm intake, 10.25:1 CR and Sniper EFI

Spring specs are: Lunati Dual Springs 140 @ 1.800, 330 @ 1.250, 1.100 Coil Bind

Those D port heads can be had in a flat tappet version with springs hood for.575” lift before coil bind and shipped set up for 120 psi on the seat, the version of the heads set up for hydro roller use is shipped With springs that can handle the same .575” lift before coil bind , but shipped with 140 psi on the seat.

Since it sounds like you have already run these heads I would say you need the new springs and here‘s why.
To use the springs the heads where shipped with I would want you to add a .030” shim to make up for lost seat pressure .
With the .540” lift exh lift of your new cam adding the needed shim would you take you up to .570” when those as shipped springs are rated to coil bind at .575”.

In short, yes get the new springs and set them up for 150 psi on the seat and then go and have fun!

Thanks a lot!
But I got the heads with flat tappet springs and later (2000 miles ago) I changed to a HR cam, so I needed new valve springs, which are the Lunati that I mentioned. Does this change anything or still better use new springs?
Butler uses these springs if you buy a set: https://butlerperformance.com/i-3123...%3DEDL-5845%2B

I posted yes to you installing the new springs.

You do need to have any springs double checked. The Crane springs SD uses for HR were a little soft at 1.800 when I checked them(bought a Rimac years ago). So they got a shim to get them to 150 and a little less IH.

Got it, but my "old" springs are rather new and they are not the springs the heads were shipped with as you assumed (probably not much pressure lost). Could change the result of your recommendation I thought.

The problem is nobody around here has tools to check the springs, so I need to trust the manufacturer a little bit more than you would. Didn't check the last springs as well.... but if they are like new, they should have about 140, which is less than you would want them to be (but not far less...).