Are the stock valves good for 150lb springs

zach right know we havent got the boost down, its pegging my 100psi gauge at a little over half to 3/4 throttle and the chargers sound like they are coming apart. anyways can i buy from u everything i need . Good to ehar ffrom ya weston i got them injectors in the mail toya today give me a call when ya get a chance we are about to go back together with this thing.
 
60# springs have almost the exact same pressure over the nose of the cam as the stock springs........crazy. I have no idea why these have been used for performance springs for so long. The reason they have the higher seat pressure but almost identical pressure over the nose is to control reversion from higher backpressure associated with exhaust brakes. 60# springs fix this but do absolutely nothing for controlling valves at higher lifts and higher rpm's. The other issue is the fact that the factory retainer weighs almost 44grams. Even if you go with Ti retainers they weigh 24 grams. Our weigh in at 11 grams. Combine the ultra light retainers and locks with the extra 15-20 grams savings in the beehive design, harmonic cancellations of the beehive springs, and enough seat pressure to keep the valves in check and you are ready for some rpm, boost and very aggressive cam profiles. If you are running larger valves, high boost pressures acting on the larger surface area of the valve forcing it open and causing reversion, and valve float caused by additional mass, something better than 60# (actually 150#) is necessary.


here is a study I did a while back:

I did some research a while back on mass of the valvetrain vs. seat pressure. This takes into account the weight of the tappets,pushrod,rocker, valve spring, locks and valves, as well as cross heads. What it does not account for is rocker ratio, nose pressure vs. mass, or acceleration rates. I'm working on the equations to factor these in, but for now basic mass vs. seat pressure is a good place to start. Remember the 12v engines have much higher lift and higher rocker ratio. 12v int 1.62-1.69 Exh. 1.66-1.688 opposed to 24v and CR which are int. 1.37-1.39 and exh. approx 1.34. (you can measure six different ones and get six different readings on 12v or 24v), which stresses the valve train much more in a 12v.

All measurements are in grams/seat pressure in LBS.



24v int.stock 4.67 F1 4.02 HD 3.4 exh. stock 5.14 F1 4.42 HD3.74
CR int.stock 4.75 F1 4.09 HD 3.45 exh. stock 5.22 F1 4.49 HD3.8


note: exh has more mass due to larger rocker arms
CR has more mass due to larger tappets

12 Valve w/ stock valves


int. stock 7.9 w/60Lb springs 4.34 exh. stock 8.5 w/60lb springs 4.62

12 valve with Haisley's Larger valves


int.stock 8.325 w/60lb springs 4.44 exh.stock8.76 w/60lb springs 4.67

As you can see 60lb. springs have about the same weight to pressure as stock 24 valve springs. What makes this worse is that 12valves have higher rocker ratios which have greater acceleration and higher lift. The greater acceleration creates obvious problems. The main issue with these springs is that with greater lift the 60lb spring does not have a high enough spring rate to control the valve on the nose of the cam. Pressure does not rise nearly fast enough to control the valve train. The 60lb. spring was designed to work better with applications where higher back pressures occur (engines with Exh. brakes) It affects seat pressure mainly and doesn't take into account higher lift cams greater acceleration rates or 5000rpm street trucks. Remember that at high lift 60 lb springs have the same pressure as stock springs. With this in mind, it is hard to believe there has not been a better spring developed to control the valves. Most people that want better springs usually end up going with double or triple small block springs which require expensive machining of the head, and create enormous spring pressures.

I hope you are not cross eyed at this point, I just wanted to give you some of my observations, and case for better springs.


And a little more
12v spring info. - Competition Diesel.Com - Bringing The BEST Together
Zach
 
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Thanks for the explanation. Never read to deep into them before. Nice piece of info.
 
yes it definitly is thats why this place is so great i can tell you that the 60# springs i had and the ones i have know are allot different i could take the 60# in my hand and squeez them together these new ones not a cahnce i can squeez them a little but very little seem like over twice the strentgh eep says they are 150# srpings.
 
I tried to explain the 60# "marine springs" to people 9 years ago and know one seemed to understand glad to see its coming to light now...lol Stock 12V are roughly 90# and a 60# marine spring as they are called are just that 60lbs on the seat more to a total of just what Zach said 145-155lbs.
 
When I did this study, it was when i was in the design phase of the springs so I never did the final numbers to compare the actual numbers to the new Hamilton springs.

On the intake with our springs the mass of the valvetrain divided by the seat pressure is 3.88gm/lbs.
the exh is 3.64gm/lbs.

what is more convincing is the numbers at 1.4" spring heighth.

stock spring 2.6gm/lb
"60lbs" spring 2.6 gm/lb
hamilton 1.74 gm/lb

this information varies depending on cam lift. What I don't have is an equation to calculate spring rate vs. ramp rate. This would show the clearest case for heavier springs. Don't forget to think about the heavy oem mass of the spring and retainers. We will save you almost 58grams per assembly.
 
Hamilton Cams said:
Tens of thousands of 60# springs have been sold that run 147-155# at the seat. 150# is no problem at all. Our drop in springs for the 12valve have 165-170# on the seat(depending on installed height) and are good to 6,000 rpm no problem. We tested them on a 12 valve that turns 5k and has almost 300,000 miles and it uses stock valves. They have been running this way for over a year and almost 30,000 miles. They are also on shot shot trucks that see almost 100,000 miles per year.

Seat pressure is not the most important factor as far as springs are concerned, nose pressure is. This is dependant on the amount of lift that your cam has, nothing else. If you run big grinds, a lot of boost and a lot of rpms, you have to run more spring pressure, no way around it. As far as tappets. 12v's have it easy even with 165# 24v's have 110#X2 or 220#, and they do just fine with millions of miles combined usage.

Zach

Zach
Click to expand...


My bad, I thought we were talking 24v......:doh:
 
Ok, whats the benieft of running the stiffer spring? Besides the obvious issues like with valve float and needs of the valve to be seated to creating cylinder pressure? Any power increases due to the stiffer spring rates. When is the valve spring too stiff or not to stiff enough?
 
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i am very interested to see how this turns out, i like revving my motor but i know im on borrowed time. i wanted to get heavyer springs like 60# but it sounds like that might not be the best idea?
 
Mike Holmen said:
Ok, whats the benieft of running the stiffer spring? Besides the obvious issues like with valve float and needs of the valve to be seated to creating cylinder pressure? Any power increases due to the stiffer spring rates. When is the valve spring too stiff or not to stiff enough?
Click to expand...

The case for stiffer springs can be divided into three parts. First, seat pressures are important to control reversion and keep the valve seated against boost pressure, and exhaust back pressure. If this does not happen, on the intake stroke when fresh air is entering the cylinder, the exhaust valve will unseat, contaminating the intake charge. If my memory serves correct, this happens about 4x psi on the exh. and around 38psi on the intake with stock valves and in the 20's for larger valves. The intake is larger and pressure X surface area =force hence the difference. If you switch to my springs and you gain some power, this is most likely what was going on. How we check for this is we have a 3/8 plate cut into a t-3 flange that we bolt to the exhaust manifold we then add a pressure regulator and then it is possible to see at what point your valves unseat. With a little soapy water it is also a good way to check your valve job. This is also why many 24v and cr engines notice over 100ft/lbs increase. With the exhaust staying shut and not letting spent gasses re-enter the combustion chamber there is more oxygen to burn later in the cycle when torque is produced easiest due to the mechanical advantage of the crankshaft and the long stroke of the cummins.

Second when using an aggressive ramp rate or spinning high rpms or both sometimes the tappet will get launched off of the opening ramp and not come in contact with the cam again until the base circle when it slams down. Sounds crazy but this can add power, due to increased lift and duration, but it is hell on the cam and the valve seats. The cams closing ramp is almost always slower so it will "gently" set the valve on the seat even though it violently opens them. Remember valve velocity is multiplied by rpm. A very aggressive ramp rate at 2000 rpm is nothing compared to an aggressive ramp rate at 7,000 rpm. This is a place the 60lbers really lose. They have NO additional pressure over the factory units at high lift. Even without adding spring rate to control the valvetrain subtracting 58 grams of mass on the fast side of the rocker arms is huge. This allows the valve to rebound much faster than the oem. Add less mass plus a better spring rate and you now can fully control valves. If you change to my springs and you loose a few ponies at the high rpms this is what was happening on your engine. If you run higher ratio rockers which greatly increase valve velocity, heavier springs and lighter hardware is a must!
A side note- this is the reason cut cams in p-pumps, especially 13mm pumps, don't live forever. Added mass of the 13mm plunger combined with much more aggressive "quick fill" cams and high rpms allow the roller to "hit" the backside of the lobe on the deceleration ramp after they have been launched off of the injection ramp, as opposed to riding the profile. Typically where they contact is where they were reground and it is also the softest part of the cam. We have heavier springs, lighter rollers, and new cams designed, but shelved the project due to lack of demand.

Third, is of less importance but still an issue. It combines mass, spring shape, and pressure. There is benefit to closing the valve, keeping it seated and not allowing the harmonics of the valve at high rpm to slightly unseat the valve.
Adding pressure ensures that the tappet stays in constant mesh with the lobe. This allows the closing ramp X rpm to determine how hard the valve closes. The spring and retainer mass also allow the valvetrain to not bounce off of the seat. Lastly the very aggressive beehive shape works very well at cancelling harmonics of the spring bounce and keeping the valve seated. On the exhaust this is VERY important especially at high rpm. At 5000 rpm the exhaust valve opens 41 times per second(if memory serves correct). This is not much time to adequately cool the valve. If what little time the exhaust valve is closed is spent bouncing, then no heat transfer from the valve to the seat can occur. Seat time and overlap(if your drive pressure is lower than boost) are the only times the exhaust valve gets "cooled". Without this valuable time valves can get "burned" exhaust valves can tulip, which I see quite often in high rpm engines. Still to date 60lb springs fly off the shelf for a lot of high dollar builds. And some vendors say that GM inner springs are all that are needed, and completely ignore the math.??????????????????????????????????wow. I always heard you can't argue with ignorance. Please question more vendors, on all aftermarket parts. You will go faster and spend less money, I promise.

Zach Hamilton
 
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Thanks Zach good info, you guys sell roller tappets on the engine camshaft? Would that help with the high rpm and mega fuel volume 13m pumps?
 
I really feel that will be necessary one of these days. Right now we are in the R&D stages on our roller cams using our cast billets. I really do not want to go to steel billets if we don't have to. It creates a lot of other problems, nothing of course that money and more machining can't fix. I don't think that roller cams have to be so exotic and expensive. We are trying to make them attainable for the regular joe.
 
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