Assembled Heads: Are my springs right for my combo?

[NewbVetteGuy]

I'd like to solicit people's links and rules-of-thumb for selecting appropriate springs, retainers, & keepers for your CAM and RPM.

I really don't understand this part of engine design/building much at all and realize that I'm just hoping that the parts that came with my assembled heads are appropriate for what I'm doing.


As you get into more RPM and more aggressive lobes, you need springs with more pressure and lighter weight valve train components, I get that, but I'd like to dive in one layer deeper to understand how much pressure and weight is appropriate for a given combo.



I have a distinct feeling that when it comes to estimating actual lifter and valve speeds and acceleration rates we're in very similar territory to calculating pistons speeds; piston speeds increase with RPM but also as the stroke increases and it's far more useful to track actual piston speeds than just simple RPM. -A more aggressive roller lobe will see lifters accelerate much faster and reach faster terminal speeds and higher rocker ratios should result in faster actual valve acceleration and movement. It should be the actual lifter / valve speeds and acceleration and weight that we're concerned with when it comes to appropriate choice of materials (weights) and spring pressures. (But I have no idea how to calculate or estimate any of this today...)




Theoretical questions aside, I'm happy to provide a real example via my engine build.

I've bought a pre-assembled cheap-ish set of aluminum Profiler heads from Jegs; I don't fully understand what hardware they came with and I'm using a very aggressive Mike Jones hydraulic roller (again aggressive for a hydraulic roller), so I can see it being quite possible that the components that came with my heads aren't super appropriate for what I have.



My components:
Jegs branded Profiler 195cc heads with the components listed here: http://www.jegs.com/i/JEGS-Performan...14032/10002/-1
Springs: 1.440" OD dual springs, (max lift 0.600" lift (my intake valve will hit exactly 0.600" lift with my cam and 1.6RRs)), 135# seat pressure, 340# open pressure (I got lucky on the math here as these ratings just happen to be at my actual closed and open heights so these are the actual pressures that will be present at least on my intake valves)
Rocker Studs & Rockers: Upgraded to 7/16"-24 screw in studs; Comp Ultra Pro Magnum steel 1.6:1 RRs
Retainers: Chrome Moly Steel 7 degree, dual spring setup (I'm expecting these to be pretty heavy)
Valves: 2.02" /1.6" stainless, 11/32" diameter, 4.910" length
Lifters: Johnson / Scorpion Short-travel hydraulic retro roller lifters ST2112SBR; 0.700" diameter wheel
Cam: Mike Jones HR70375-71360-110; Duration @ 0.050": 227/228; Duration @ 0.006": 272/280; lobe lift: .375"/.360"; max lift w 1.6 RRs: 0.600" / 0.576"; LSA 110, 107 ICL; powerband 2,400-6,400 RPM; peak @ 6,000 on 350


So I'd like to spin it to 6,300 RPM, but the fast ramp cam has 227 deg duration and still gets the valves up to 0.600" so it's a pretty fast valve accel and speed and most of the components are pretty heavy (stainless valves, hydraulic roller lifters, dual springs, chrome moly retainers;

-Should I upgrade to lightweight tool steel 10 deg retainers to save some weight?
Are my springs heavy enough for this application?

I'm getting different feedback from people in real life and on the internets; some say that even though my intake valves' max lift is the same as the springs' max rated lift that the extra 0.050" that's usually baked into these "maximum's" means that it's ok; some other people are telling me that I'll overheat the springs and they won't last long. Some people are telling me that with my heavy valve train, I don't have enough seat or open pressures and I should just buy some beehive springs and tool retainers now before I install the heads.... I don't know what to believe any more...


For what it's worth: My plans are to put 25k-30k miles on the engine and pull it and install a stroker kit; if the current springs will work for 25k-30k miles I'll just replace springs and retainers then.

Adam

[mark_follweiler]

what does Mike think?

[Keith Morganstein]

I've used those HR lobes and similar from Jones cams.
I set them up heavier than that. Usually around 160 closed (seat) and around 380- 400 open with 11/32" stainless valves and steel retainers.
Mile can tell you if those springs are enough.

[ProPower engines]

I would switch to a 10 degree retainer and lock without even going any further.
The territory you are entering will beat up them tiny 7 degree locks in no time. Tool steel retainers are lighter and cheap way to lighten up the valve train combined with a 10 degree lock it will be much safer and more durable in the long run

[Reef]

<t>I agree, change the retainer combo because the small 7' stuff is inadequate. Be sure to have a quality spring seat that properly fits/locates the springs( when the springs aren't dancing around they do a much better job) you see a lot of preassembled heads lacking there. The pressures will be ok but for the small additional cost of springs another 30 lbs would be a nice safety margin, although really unnecessary if your max rpm will REALLY be only 6300. Oh yeah and physically measure coil bind clearance.

[Newold1]

If your Jones camshaft is one you purchased from or thru Mike, he designed and ground that camshaft he is with his years of success and expertise definitely the best one to run this question by! He knows the ramp and lobe profiles and can definitely give you some of the best advise.
As for the retainers, yes, definitely good advise to use the lighter weights in the applicable valve train and the greater strength is a plus.

My thought is you are probably going to end up with a spring set that has more closed and open pressure than you are currently equipped with and if the spring seats will accept a larger diameter spring that would be a plus in my book. In any event you should measure all springs and get them close in installed pressures and always spend more for better springs, cheap springs are time bombs in most engines, PSI, Pac, Manley, ISKY, etc. .

[NewbVetteGuy]

what does Mike think?

Point taken, I need to call him. I'd still like to understand more about how you estimate what spring pressures to use for a given engine.

I've read some posts on here from David Rez on actual calculating this, but I have zero hope of getting the duration at all lifts necessary to use that method and estimates and rules-of-thumb are good enough for me right now.



Adam

[BigBlocksOnTop2]

At .600 lift and a 4.910 valve, do you have enough spring installed height?

[NewbVetteGuy]

<t>I agree, change the retainer combo because the small 7' stuff is inadequate. Be sure to have a quality spring seat that properly fits/locates the springs( when the springs aren't dancing around they do a much better job) you see a lot of preassembled heads lacking there. The pressures will be ok but for the small additional cost of springs another 30 lbs would be a nice safety margin, although really unnecessary if your max rpm will REALLY be only 6300. Oh yeah and physically measure coil bind clearance.

I was just about to ask about 7 degree vs 10 degree retainers & the spring seats.

My heads did NOT come with spring seats- the springs are just sitting directly in the aluminum head spring pocket...

Really regretting buying pre-assembled heads. I already replaced the rocker studs, now it sounds like I'll be buying springs, retainers, locks, & spring seats. The valves and valve guides aren't looking so cheap anymore....


Adam

[NewbVetteGuy]

I have another dumb question: My cam's exhaust lobe has slightly less lobe lift and slightly more duration than my intake lobe; it also should have a lighter weight valve as it's 1.6" vs. 2.02", so shouldn't I be using springs with less seat and open pressure on the exhaust valves than the intake valves?

Why do I almost always see the same springs on intake and exhaust when the goal is to use the lightest spring that can adequately control the weight for your desired max rpm?



Adam

[mtrhead]

I've used those HR lobes and similar from Jones cams.
I set them up heavier than that. Usually around 160 closed (seat) and around 380- 400 open with 11/32" stainless valves and steel retainers.
Mile can tell you if those springs are enough.

I have a similar but bigger Jones roller , GM roller lifters, with Profiler heads, same valve length, spring cups, and 10 locks (stock sbc length)

Springs: PSI #LS 1511 ML Beehive... Seat 130 lbs @ 1.800" Height Open 370 lbs @ 1.175" Rate=384.0" Max lift 0.625" 1.100"

[NewbVetteGuy]

Update:

Mike Jones got back to me and recommended the following pressure options for a hydraulic roller @6,300 RPM with my cam:
#1 Traditional Double-Spring: 155 lbs closed; 435 lbs open --The closed rate isn't terribly far off and going with lighter retainers could help at a bit and make this acceptable; obviously my current springs open pressures are nowhere close.

#2 Beehive Springs: 145# open; 358# open

My heads came with 1.440" OD dual springs, with a max lift 0.600"; 135# seat pressure; 340# open pressure and 0.075" between max lift and coil bind.
The spring rate was 328 lbs / inch so if I shimmed the springs the max I'd feel safe another 0.015" that would only gain me and additional 5# and I'd end up with my current springs @ 140# closed; 345# open. -WAY far from what Mike said I need for double-springs @ open pressure.



I think I want to go with Beehive springs and lightweight 10 degree tool retainers and locks.
Mike recommended these springs @ 15.24 a piece and I'll probably go with them, but I want to see what cost an equivalent from Comp would cost: http://www.racingsprings.com/Beehive-Si ... X/Item/784 <- with my 0.600" max lift the springs will compress down to 1.200" open and be at 349.5 # fully open if I did the maths right.



Moving on ever-so-slightly: Am I ok with a high rpm, low bleed-down Johnson lifter @ 6,300 RPM and 350 # open pressure or is this much spring pressure going to cause issue with my hydraulic lifters?


From another ST thread from a while back Mike Jones posted some typical ranges of bleed down rates for different lifter types:
A std OEM hydr lifter has a Leak-down rate of about 20-80 seconds.
A "variable duration" hyd lifter (AdamEdit: Rhodes) has a Leak-down rate of about 8-20 seconds. This will make the cam act smaller at low RPM's(when the oil pressure is low),
then act normal in mid RPM's(as the oil pressure increases), then act small again, as the pressures working against the lifter, overpower the oil pressure.
A "High RPM" hydr lifter has a Leak-Down rate of about 90-120 seconds. This will make the cam act a little larger at low RPM's, but will not bleed down as much at higher RPM's, and can handle more spring pressure.

So given that my lifters should have somewhere between 2x and 6x a typical oem bleed down rate and given that I'm only spinning to 6,300 RPM, even though I have a heavy valve train and a very aggressive hydraulic roller lobe, I'm guestimating that I'm in the clear. -Anyone see things differently?



Adam

[Newold1]

I am not now a big fan of a lot of beehive valve springs. I have seen and been involved with beehive spring issues. I have been studying the new conical valve springs and my thought is you should look at the new Comp 7256-1 valve spring, its specs. and benefits. You might also ask Mike what he thinks of them. They are designed to work with aggressive camshaft profiles and they could be a better choice for that cam of Mikes.

[jsachs1]

I prefer to not use beehive springs. When 1 breaks, well you know what hits the fan.

[MadBill]

I have another dumb question: My cam's exhaust lobe has slightly less lobe lift and slightly more duration than my intake lobe; it also should have a lighter weight valve as it's 1.6" vs. 2.02", so shouldn't I be using springs with less seat and open pressure on the exhaust valves than the intake valves?

Why do I almost always see the same springs on intake and exhaust when the goal is to use the lightest spring that can adequately control the weight for your desired max rpm?*



Adam

*Just to be clear, should add: "...with as much over-rev capability as you think necessary." E.g., an automatic-equipped car with a rev-limiter has less over-rev potential than a manual without. That said, some reasons for spring commonality:

o Convenience; can't mix them up.
o The exhaust springs pick up more engine heat, reducing their performance and life. (If you line up all the springs from a high-mileage engine, the exhausts' free length is usually less.)
o Since the exhaust valve is closing as the piston arrives, it is the one that gets tagged if it's not following the dictates of the lobe, so a little more spring force is cheap insurance.