[6spdhyperblue]

I’ve had a bad batch of aftermarket valve springs once. I would think about weighing your risk of new spring vs proven old spring depending on how worn they are

[KingLT1]

The PSI 1511's are some of the best beehives ever made. I don't recall one failure ever being reported with those springs and they have been used countless times on mild LS builds. They are 130/380 and rated up to .625 lift which will work with a lot of cam motion grinds.

[oldman]

Originally Posted by Tim M

CMitchel17: Only way to check for spring fatigue is to remove them (don't believe one can do on-LT-head checks) and check the pressure. At the price they sell them, I'd rather just start fresh each time.

Ref. Ti valves: I've not heard of a compatibility concern with the seats. Wonder if lower RPM's and/or the softer spring pressures for the supercharged variant might be the benefit. We are considering the factory Ti valves to reduce weight and increase valve float rpm.

Oldman: Little confused with your 'not enough spring' comment toward the beehive? I'm using BTR's valve spring kit (BTR GEN V SPRING KIT WITH .625 LIFT / 1511/5071BH/BB). I'm hoping the same set will be compatible with a new cam (under .600 lift) and rev to 7000 rpm - seems like this would apply to your combination as well?

I think GM with DoD needed to go to the lightweight valves. I see nothing wrong with starting with LT4 heads, replace the exhaust valve with an inconel ProFLow, beehive springs.

My thought is that a beehive spring is not enough spring for these big cams with aggressive ramps. The beehive concept is to get a lighter retainer at the top, it fundamentally does NOT cancel out valvetrain harmonics. Dual springs and conical springs do. We as humans think the spring is always pushing open but in actual use there are multiple harmonic resonance going up and down the spring and actual open pressure at any point in time could be drastically LESS than what human can imagine, this is bad if and when that harmonic is at the same time as the deceleration ramp. (which it probably is as the motion of the spring has peaked down and now there is a reversal of direction. .i.e slowest speed but greatest acceleration, a second derivative).

The conical by design cancels the harmonic out via asymmetric winding / spring design. The dual springs just use two springs with two seperate harmonics. Hence I like the conical but they are mostly designed for 3/4 street applications and have too much open pressure for a 100K valvetrain. Granted my sub .600 lift cam probably would have 80 lbs less open pressure.

I like the dual spring design because it is proven and I like the increase in surface area for oil cooling. Springs get hot, road racing is hot, FI is hot, I like the idea of lots of metal to cooling oil surface area.

The TSP dual spring I have is just once again a little on the stiff side, but seems to work fine in my mild ramp CamMotion application. My previous cam was a custom supercharge cam from TSP and I got it for free with my second hand supercharger. Looking at the lifter failure, I noted that the declaration ramps looked worn (on the non failed lifters). This may indicate that the TSP dual spring kit was NOT holding the lifter in contact with the cam, I think my fuel cut back then was 6600 RPM.

I may or may not pull the valley cover on my engine just to check the cam lobes (lazy). My current setup is 7200 RPM fuel cut, TSP dual springs and a sub .600 lift stable ramp CamMotion cam, they are know for stable ramp profiles. No this cam will not make the same HP as an equivalent TSP cam.

[6spdhyperblue]

Originally Posted by KingLT1

The PSI 1511's are some of the best beehives ever made. I don't recall one failure ever being reported with those springs and they have been used countless times on mild LS builds. They are 130/380 and rated up to .625 lift which will work with a lot of cam motion grinds.

True mine were pac1518

[oldman]

https://www.chevyhardcore.com/tech-s...sign-dynamics/

looks like the dual spring actually has more pressure on decel ramp, but the conical is way better on the seat.

[cmitchell17]

Originally Posted by Tim M

CMitchel17: Only way to check for spring fatigue is to remove them (don't believe one can do on-LT-head checks) and check the pressure. At the price they sell them, I'd rather just start fresh each time.

Ref. Ti valves: I've not heard of a compatibility concern with the seats. Wonder if lower RPM's and/or the softer spring pressures for the supercharged variant might be the benefit. We are considering the factory Ti valves to reduce weight and increase valve float rpm.

Oldman: Little confused with your 'not enough spring' comment toward the beehive? I'm using BTR's valve spring kit (BTR GEN V SPRING KIT WITH .625 LIFT / 1511/5071BH/BB). I'm hoping the same set will be compatible with a new cam (under .600 lift) and rev to 7000 rpm - seems like this would apply to your combination as well?

So I don't see the theory behind checking the spring force and being able to equate it to gauging the springs useful life. As a disclaimer I am saying this just from my own knowledge and I need to read up on the subject probably. I just don't know of anything that says the modulus (stiffness) of the spring should change as it accumulates fatigue damage, but maybe there is something more going on materials wise with modern treated springs that I don't know about.

And I thought I recall reading something about why the LT4 uses titanium, they obviously had a bigger budget for the LT4 but I don't think it was just about heat (more power so more waste heat than LT1). I would think the LT4 seats would have to be different than the LT1.

[Baddawg53]

Originally Posted by cmitchell17

How did you gauge the life of your springs to know they were bad?

It was mostly based off a recommendation from the shop that reworked my heads. I pulled them off to upgrade the lifters, and I was burning a little coolant. He tested the old springs and said they were nearing the end of their life. I never did get the numbers from him.

[Tim M]

CMitchell17: I've always understood valve springs are a wear item. The more stress, the less life. If they incur valve float, the pressure can drop significantly. Usage over time drops pressure/life.

NA builds seem to have folks rev the engines higher than a supercharged one (especially an LT4 with its 'small' size).

Wonder if LT4's have Ti valves because of the blower pressure killing some of the 'installed pressure' on the intakes. GM didn't want to add more pressure to compensate due to the DOD lifters limited pressure tolerance. Might even be a cam phaser issue as I've read too much pressure will impact its operation. If no more pressure is allowed, they drop valvetrain weight to fight valve float. $90 valve is a pretty expensive upgrade for GM to choose.

Oldman: Appreciate the notes on the spring comparison. No argument. The slow motion videos are eye-opening. :-)
My one experience with a the beehive resulted in significant gains over a recommended dual spring with a Ti retainer. The ~1000 rpm gain before valve float was enough for me to be convinced and I used them for several years - changing out the $175 set annually.

[KingLT1]

Originally Posted by cmitchell17

So I don't see the theory behind checking the spring force and being able to equate it to gauging the springs useful life. As a disclaimer I am saying this just from my own knowledge and I need to read up on the subject probably. I just don't know of anything that says the modulus (stiffness) of the spring should change as it accumulates fatigue damage, but maybe there is something more going on materials wise with modern treated springs that I don't know about.

And I thought I recall reading something about why the LT4 uses titanium, they obviously had a bigger budget for the LT4 but I don't think it was just about heat (more power so more waste heat than LT1). I would think the LT4 seats would have to be different than the LT1.

When springs are nearing the end of their life span they weaken. So a 130lb spring may only test 115-120lbs. That is when you know it's time to replace them.

[oldman]

Originally Posted by Tim M

CMitchell17: I've always understood valve springs are a wear item. The more stress, the less life. If they incur valve float, the pressure can drop significantly. Usage over time drops pressure/life.

NA builds seem to have folks rev the engines higher than a supercharged one (especially an LT4 with its 'small' size).

Wonder if LT4's have Ti valves because of the blower pressure killing some of the 'installed pressure' on the intakes. GM didn't want to add more pressure to compensate due to the DOD lifters limited pressure tolerance. Might even be a cam phaser issue as I've read too much pressure will impact its operation. If no more pressure is allowed, they drop valvetrain weight to fight valve float. $90 valve is a pretty expensive upgrade for GM to choose.

Oldman: Appreciate the notes on the spring comparison. No argument. The slow motion videos are eye-opening. :-)
My one experience with a the beehive resulted in significant gains over a recommended dual spring with a Ti retainer. The ~1000 rpm gain before valve float was enough for me to be convinced and I used them for several years - changing out the $175 set annually.

This is my thinking

[Timbo-1LE]

Originally Posted by cmitchell17

I don't see where you could tell much from an oil analysis? What specific metals would you be looking for? Is there a way you could look for valve spring failure? As far as I know the valve springs fail by fatigue and not be wear so I don't know how you would detect that?

What specific metals would you see in a early lifter failure?

A stethoscope seems like the more reliable tool and being able to detect a change in sound.

The way people talk about how aggressive some of these shops lobes are along with how many personal stories they have of failures, you would think your motor is about the blow up any second.

You rarely hear talk of how high of a RPM you can push these motors too, I hear rod bolts are the limit, but then I don't know if that comes from someone just saying that or evidence or what.

I run mine at a 7275 rpm extreme cutoff, this allows me to shift at 6950 rpms and have enough room to not bounce off the rev limiter when the tires spin. I initially had it at 7200, but I had to bump it up to not hit the rev limiter when spinning. I came to the 7200 conclusion not from any evidence or analysis or testing but just guessing. I realize there's no RPM limit where its going to blow up or not, but if you look at the GMPP 535 LT1 hot cam crate engine, the extreme rev limit is at 7100, and the LT1 im pretty sure has stock valve springs, I think LS7 lifters?, and stock everything else I think? So I figured I was still safe at 7275.

Agree on LT1 hot cam, some of you are aware I had Katech install that with their head work... They set the extreme just below 7300, I'm having to learn to wind it up and use a lower gear on road courses... Never missed a beat, rev's like blender above 4k....

[Katech_Mike]

Originally Posted by KingLT1

The PSI 1511's are some of the best beehives ever made. I don't recall one failure ever being reported with those springs and they have been used countless times on mild LS builds. They are 130/380 and rated up to .625 lift which will work with a lot of cam motion grinds.

We've used PSI springs in almost every build(LS & LT) for over 10 years now. We have never had a spring failure that I can recall. I always recommend that the springs are changed every 30,000-40,000 miles in a street/strip application.

If you're beating the axle out of the lifter you likely have some valvetrain stability issues that need to be addressed.

[cmitchell17]

Pretty sure I just broke a valve spring. I had just pulled the valve covers off and put slightly longer pushrods in, 7.725 in long ones and pulled out the 7.750 in ones, I was trying to quiet it down and it would put my average preload at around 0.056 from 0.031 which could be a little much.

Anyway a few hours after I revved it up once and starting hearing what sounded like a lose piece of metal bouncing around in the valve cover. I limped it back home and the noise went away but only at low rpms, when you rev it up past 2000 you start to hear a faint noise.

So now hear I am after refusing to spend $150 on a proper valve spring tool for the LT reversed and splayed valves, I can't get the retainers off again. Last time I did this I had the whole head out and I clamped the heat down to the bench so the valves would stay put, but I really don't want to have to pull the head just to check if this valve spring is actually broken, especially since everything might be fine and this might be something else.

Anyone have any ideas? I feel like my only other option would be to try to position the #7 cylinder as close to TDC as possible and try to brace against the piston but don't want to mess up the valve of course. I am pretty sure its the #7 since I was getting a random misfire code and a #7 cylinder misfire code. This #7 cylinder was also the same one that tore up the intake valve seat as well, not sure if there is something about the #7 that makes the valves get beat up worse.

I guess another thing I could do is leave the #7 rocker arms and pushrods off and try to run it and see if I hear the noise to confirm its actually #7.

[cmitchell17]

So after turning the regulator way up on the leak down tester it put enough pressure on the valves to pop the retainers out.

Now the problem is I can't find anything wrong with the springs they look fine.

All the rest of the springs on both banks look perfectly fine and nothing else wrong I can see.

I am thinking maybe the misfire code came from when I pulled the FSCM fuse trying to bleed the fuel pressure down to get the fuel line off and maybe unrelated. I know when I logged it when the noise started I didn't see any misfire counts at least I think.

Sorry I don't want to hijack the op's thread, but I am thinking maybe I did something really really dumb. Looking back at what I wrote down I only clayed a MIN of 0.062 on one bank and 0.075 in on the other bank. With the new pushrods I put in, I went up 0.025 in to 7.750, so I think there is a real good probability I might have had some piston to valve contact:





So the min PTV I clayed at 0.062 is luckily the exhaust side and if I am hitting the piston it shouldn't be as bad as the intake and its on a radius as well.

So this could be the only explanation I can think of, with the intermittency and non-consistency of the noise. It sounded like something loose bouncing and rattling around. I guess I need to go back to the 7.725 pushrods and hope I don't have some piston or valve chunks floating around.