Hydraulic roller spring selection

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Hydraulic roller spring selection

Post by Aussie Chrysler » Tue Nov 19, 2013 12:52 am

Original thread was here before it went a bit off topic (Coil bind versus max lift): viewtopic.php?f=1&t=37604

My original question was about minimum coil bind for a hydraulic roller setup (230/238@.050", .580/.600" in a smallblock Chrysler with Edelbrock heads - same 1.800" installed height as LS springs).

Current beehive springs (Pac 1218x - 140lb@1.800" and 313lb rate) aren't cutting it. Bought some Manley beehive springs (150lb@1.800 and 353lb rate) and the box recommends coil bind clearance of .050" and says only increase it by .050" "maximum if necessary" to prevent coil surge.

That's .050"-.100" recommended coil bind clearance.

So it looks like I will need to install these about 1.76"/1.78" in/ex to get within range (allowing up to .020" lost through pushrod geometry on a .580/.600" lift cam/rocker combo). That will give me seat pressures of about 160-165lb and open pressures of 360-365lb.

That shouldn't be too much seat pressure for a set of Crane retro hydraulic roller lifters, should it? Crane says its HR lifters are good for more than 360lbs of open pressure. This is for a street/strip car (11s) that sees a fair bit of cruising.

It's not too late for me to get a set of PSI LS1511ML springs (130lb@.1.800" and 384lb rate) and shim them to 1.750" for 150lb seat pressure and 365lb open pressure - same open pressure, but 15lb less seat pressure than the Manleys.

The current soft-rate (313lb) springs are good for about 6300rpm before things get unstable. I'm aiming for about 6800rpm with 2.05 valves in a 408 stroker. I reckon the 353lb springs with a little extra seat should do it, but are there any drawbacks to having too much seat pressure for the same open pressure? I've got decent .105" thickwall Trend 5/16" one-piece pushrods and solid T&D 1.65 rockers, so valve train flex shouldn't be a problem at those rates.

Thanks again.

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Re: Hydraulic roller spring selection

Post by user-3597028 » Tue Nov 19, 2013 1:59 am

If you think your rpm problem is related to the valve bouncing off the seat when closing, then increasing seat pressure is the answer.
If the problem is that there is not enough open pressure and they are "lofting" and letting the lifters pump up, you won't see a change by increasing seat pressure.
If the lifters are, in fact, bleeding down at high rpm, you are effectively "losing camshaft action" , like your cam shrinks at speed. This can be counteracted by preloading the lifter much further down.

On some high rpm Hyd. Rollers, we run them with a lot of pressure (200/550), adjusted just off the bottom of their travel. You just let it bleed down and act like a solid at high rpm. This is how Harley "hydro solid" lifters work. They don't have enough oil pressure to actually make the lifters work properly, so they run them adjusted in this fashion.

You will see that "short travel" hyd. rollers that are being sold today are set up to run like this.

I think the common misnomer that lifters actually "pump up" from oil pressure rather from slack in the valvetrain system is flawed logic.

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Re: Hydraulic roller spring selection

Post by Aussie Chrysler » Tue Nov 19, 2013 2:12 am

I suspect that the seat pressure is enough, but that the current spring (313lb) doesn't have enough rate to keep up with the closing ramps of the cam. I had a higher rate conventional spring (345lb) with lower seat pressure (120lb) before I went from 1.5 to 1.65 rockers, and that handled 6900rpm. Going to the bigger rockers (same cam) obviously means more lift and faster rates. Switching to a beehive (about 40g lighter springs and retainers) has worked to an extent, but I know I need the extra rate.

Lifter preload is right in the middle - about .040" (.020-.060" range). Oil is 15W-50. I don't think pump-up or bleed-down are issues, but I can't be 100% certain since the rocker ratio change. But we're only talking around 6500+rpm and it's not a huge cam. Crane does recommend a softer seat (112-125) higher rate (400+) conventional dual spring for this cam. I'm running higher seat pressures, but aiming for similar opening pressures (with a slightly lower rate) beehive.

The main issue is likely to be the heavier rocker (T&D versus Crane), which has negated the lighter spring and retainer combo.

EDIT: Maybe you can clarify . . . I've read on here that if you reduce lifter preload (even to the point of running lash instead of preload), you prevent pump-up because the lifter now has nowhere to pump up - it's reached the end of its travel (Crane does not recommend this, obviously, as it puts strain on the plunger circlip and could lead to failure). By increasing the preload, aren't you creating more room for the plunger to "pump up" if the valve-train separates? Instead of being able to pump up .020" to the end of is travel, it can now pump up .060" instead.

Isn't it the same principle as bleed-down but in reverse?

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Re: Hydraulic roller spring selection

Post by user-3597028 » Tue Nov 19, 2013 6:21 am

Aussie Chrysler wrote:I suspect that the seat pressure is enough, but that the current spring (313lb) doesn't have enough rate to keep up with the closing ramps of the cam. I had a higher rate conventional spring (345lb) with lower seat pressure (120lb) before I went from 1.5 to 1.65 rockers, and that handled 6900rpm. Going to the bigger rockers (same cam) obviously means more lift and faster rates. Switching to a beehive (about 40g lighter springs and retainers) has worked to an extent, but I know I need the extra rate.

Lifter preload is right in the middle - about .040" (.020-.060" range). Oil is 15W-50. I don't think pump-up or bleed-down are issues, but I can't be 100% certain since the rocker ratio change. But we're only talking around 6500+rpm and it's not a huge cam. Crane does recommend a softer seat (112-125) higher rate (400+) conventional dual spring for this cam. I'm running higher seat pressures, but aiming for similar opening pressures (with a slightly lower rate) beehive.

The main issue is likely to be the heavier rocker (T&D versus Crane), which has negated the lighter spring and retainer combo.

EDIT: Maybe you can clarify . . . I've read on here that if you reduce lifter preload (even to the point of running lash instead of preload), you prevent pump-up because the lifter now has nowhere to pump up - it's reached the end of its travel (Crane does not recommend this, obviously, as it puts strain on the plunger circlip and could lead to failure). By increasing the preload, aren't you creating more room for the plunger to "pump up" if the valve-train separates? Instead of being able to pump up .020" to the end of is travel, it can now pump up .060" instead.

Isn't it the same principle as bleed-down but in reverse?
If you have a lifter with a ball and check system that will tolerate zero lash and not bleed down at high rpm, that does work...sometimes. The problem is, with the spring load necessary on many combinations and the weight of all the parts, including the lifter, it doesn't always work out. By increasing preload, you only have a limited amount of bleed down that can occur. If you have separation in the valve train, you have a spring problem and all the lifter adjustments in the world won't help you. Running zero lash may only be a crutch to a inadequacy in the spring.

Every engine is different and may act different. We have had big blocks that fell on their faces at 6200 with zero lash and when we installed a .150" longer pushrod and preloaded them all the way down close to the bottom, they sang right up to 7000. Then, others that would do the exact opposite!

You should have no problem running a lifter at zero lash if it has a circlip, (facing the correct direction). A solid lifter works the same way. I wouldn't lash them, simply because it would be hard on the roller bearing. The lobe profile is designed to be run with 100% contact.

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Re: Hydraulic roller spring selection

Post by user-3597028 » Tue Nov 19, 2013 6:36 am

See, what really got me thinking about these engines having uncontrolled bleed down was my first work with performance Twin Cam Harleys.
See, they have a pretty poor oiling system, but, they use the same lifter as a late model Chevy hyd. roller. The spring pressures at the time were in the 180-200# on the seat and as high as 440# open. It's was a pretty standard deal for most performance type heads and springs.
Depending on the thread pitch of the adjustable pushrod used, they would have you preload them 3-4 turns down. This was real close to the bottom of the travel. It is a real tedious job and takes time if the lifters are pumped up.
We tried to run them with less preload once and the engine sounded like every part in the valvetrain was going to fly out well before 5000 rpm. Preloading correctly them solved this.
Now, we use all 7mm valves and lightweight beehive stuff and run seat pressures in the 165/340 range. These things rev to 6500 like nothing. This is with the same lifters.

Sorry for the ramble, just something more to think about.

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Re: Hydraulic roller spring selection

Post by Aussie Chrysler » Tue Nov 19, 2013 7:02 am

No, it's interesting to read. Essentially what you're saying is run a heavier spring to prevent the valvetrain from separating and the lifter pumping up, and then preload most of the oil out of the plunger as a precaution against excessive bleed-down (with the heavier springs) - the opposite end of the spectrum.

Harley Davidsons have pretty long pushrods, don't they? Mine are only around 6.75" (the beauty of having a high cam tunnel small block Chrysler - lots of room for a bigger crank, too). It's interesting you still run 165lb on the seat with all that lightweight valvetrain and long pushrods. Makes me feel better about running 165lb seat pressures on mine.

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Re: Hydraulic roller spring selection

Post by Aussie Chrysler » Tue Nov 19, 2013 7:08 am

Probably worth mentioning that Chryslers don't oil through the pushrods, so once the oil is in the lifter, it really has no where else to go except reverse its flow. With a high-volume oil pump (and oil galleries that feed the cam before the mains = lots of pressure), bleed-down may not be so much to worry about in my engine. I haven't built enough of these things to know for sure, though, so just a theory . . .

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Re: Hydraulic roller spring selection

Post by user-3597028 » Tue Nov 19, 2013 7:32 am

Aussie Chrysler wrote:Probably worth mentioning that Chryslers don't oil through the pushrods, so once the oil is in the lifter, it really has no where else to go except reverse its flow. With a high-volume oil pump (and oil galleries that feed the cam before the mains = lots of pressure), bleed-down may not be so much to worry about in my engine. I haven't built enough of these things to know for sure, though, so just a theory . . .
The bleed down seems to be related to the plunger to body clearance and the check ball assembly. Lifter to lifter bore clearance can affect it too. On the Harleys we regularly hone for oversize lifters to tighten this "leak" up.

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Re: Hydraulic roller spring selection

Post by Orr89rocz » Tue Nov 19, 2013 8:01 am

What are the .050-.200" duration numbers? I would have thought that heavier beehive would easily control that valve size.

Is the rocker geometry setup properly? That makes a big difference.

Your heads being 1.800" install height means you share same height as late model gm lsx motors and there are tons of great springs for them.

I ran a 286/306 230/245 .603/.613 hyd roller in my 383sbc using afr 195 with 8mm stemmed 2.05 valves. Afr 8019 springs, shimmed 1.775 or so. Thats a 1.27" or 1.29" diameter dual thats 150 ish seat at 1.800 and 412 open at .600" i think. Very popular size spring for lsx motors. I spun 7k no issues. Should be 165-170 lbs seat at my height.

I now have a big heavy 2.100" sbc valve, .640" spinning 7100 under 15-16 psi boost, no float with morel lifters and 3/8" pushrod. Shaft rockers for proper geometry. My first setup with stud rockers i must have set it up wrong and it floated by 6200. Ate my guides. Geometry is king. My springs are 180 seat and 450 open

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Re: Hydraulic roller spring selection

Post by Aussie Chrysler » Tue Nov 19, 2013 9:35 am

230 and 150 on the intake, 238 and 158 on the exhaust. Full shaft rocker system (Mopar), T&D rockers, Trend .105" 5/16 pushrods, 117g 2.05" intakes, 100g 1.60" exhaust valves. Valvetrain should be very stable. Rocker geometry is correct.

I'm running LS beehives because the T&D rockers foul some larger retainers. I'm sticking to beehive springs because I have spring locators and retainers to suit, and because they clear the T&D rockers. The strongest ones I've found that will fit my application are 130lb@1.800 and 384lb rate (PSI mentioned above).

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Re: Hydraulic roller spring selection

Post by Orr89rocz » Tue Nov 19, 2013 9:47 am

There are tons of small diameter duals with various rates to get the job done but i dont see how you could have major issues turning rpm with that cam and a decent spring that has 165 lbs seat, closer to 400 open. Titanium retainer would help that valve is pretty heavy for the diameter. Mine is abit heavier still but running 180/450 lb springs. I have 1.37" diameter springs and clear my LGM rockers fine. Most rockers i thought clear 1.500" springs since most solid roller race stuff is in that range 1.4-1.55"

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Re: Hydraulic roller spring selection

Post by Aussie Chrysler » Tue Nov 19, 2013 11:51 am

Beehive springs (72g) and retainers (10g) are pretty light. Rockers not so. I'm looking at 165/370 with the new beehives I've just bought (installed at 1.750"), up from the current beehives that are 140/320@.580". Current beehives get me to about 6200-6300 safely, but you can feel the power drop off after that and the valves start to float at about 6500 or just under.

For comparison, with 120/300@.528" (old 1.5 Crane rockers) conventional singles with dampers (heavy springs and retainers), I could wring it to 6900 and shift at 6600. Power band has moved up another 200-300rpm with the bigger 1.65 rockers (.050" more lift; few degrees more duration @.050") and a bit of head work, including 2.02>2.05" valves, so I really need to get my old revs back. I need another 400-500rpm.

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Re: Hydraulic roller spring selection

Post by Seanh832 » Wed Nov 20, 2013 6:55 am

Ever considered running a rev kit? It may solve your problem Without overloading the plunger. Mine works great with a hydraulic roller at 248/254 with .615" lift and similar pressures. Runs well to 7000 rev limiter and im sure it would rpm higher without issue.
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Re: Hydraulic roller spring selection

Post by Aussie Chrysler » Wed Nov 20, 2013 10:18 am

Well, if you can find me a rev kit for a smallblock Chrysler, I'd certainly consider it!

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Re: Hydraulic roller spring selection

Post by dave brode » Sun Jan 26, 2014 10:54 am

Seanh832 wrote:Ever considered running a rev kit? It may solve your problem Without overloading the plunger. Mine works great with a hydraulic roller at 248/254 with .615" lift and similar pressures. Runs well to 7000 rev limiter and im sure it would rpm higher without issue.
I know that it's off topic to the mopar OP, but on the subject of rev kits for hyd: there are kits for retro-fit style lifters, but ARF actually makes a setup for chev factory style hyd rollers. Although, it is 2x the price of most kits.

http://www.summitracing.com/parts/afr-6155/overview/

I've seen rev kits for big block mopars. Is there nothing for the sb mopars?

Dave

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