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?



Adam

gkull

No, for several reasons. Never run a spring near max lift rating. Springs run cooler and last longer. Springs can loose 20+ pounds of seat pressure within months of installing them.

AFR H-roller spring sets are generally in the 145 - 150# closed and high 300# to lower 400# closed. If you are lifting a valve .600 You want to have spring installed height to allow for .640 - .700 inches.

You can get on the Comp Cams Spring chart pdf and figure out some spring that would work with your installed height. Are your existing springs shimmed up?

I'm for Beehive springs because of valve control without higher pounds and the tiny retainers are a weight savings where you need it.

http://www.compcams.com/technical/va...art/216-06.pdf

NewbVetteGuy

@#%$#@%#@!!!

I initially asked Mike Jones when I purchased the cam and he seemed to think that because the springs have a degree of safety built into them that running with 0.600" lift would be fine.

What you're saying is that the pressures aren't high enough for the rest of my combo.


Instead of replacing the springs, can I get a better margin of safety by reducing weight by replacing the retainers and keepers???



Adam

gkull

I was just looking at the CC spring chart. I've used these

26120 beehive 1.900 installed height 148# closed and 370# open max lift of .650

26924 beehive 1.800 installed height 146# closed and 335# open max lift of .650

26055 beehive shimmed to 140#

gkull

I was building 6500 red line H-rollers without valve float.

Max lift and coil bind is often .050 apart is the safety margin Mike Jones was talking about. will it work.... yes for less running hours on the engine.

Lighter weight roller lifts and retainers are always a plus. I use 10 degree locks and on some motors titanium retainers

PainfullySlow

Dave Vizard has written entire chapters about this and the manufacturers today complicate things by having a bazillion (yes that is a technical term) different options available.

I would definitely go with a beehive spring as it allows higher revs but when it comes to the rest I would be on the phone with the cam provider and asking for a specific recommendation...as in: give me a part number that you would use.

You have spent a fair amount of money with that company...make him work for it.

NewbVetteGuy

Let me ask a follow-on question. If I run it with the included spring & retainer package and set my red-line @ 6,100 RPM; after how many miles would you replace the springs and retainers?


If it will work, just for fewer hours / miles, I'm going to be pretty tempted to just run them as-is and then replace the springs and retainers at a later date.


Adam

gkull

always an option. I have a spring pressure checker it attaches to the studs kinda like your spring compressor. So I learned to periodically check my springs. If my 220# seat pressure gets below 195# I replaced them. With your mild cam and low 130 seat pressure I would not let them go down over 15#

derekderek

Never ever ever ever use valves and springs from cheap bulk production heads. The castings are ok, for the most part. The valves and springs are cheap trash.

NewbVetteGuy

yea... I looked at prices and from what I can tell $250ish range is just not going to happen.


I'm thinking I'm going to put 25-30k miles on this thing and then I'm going to pull the engine and put in a stroker kit and that would be a great time to put some new springs & retainers on it. -Thoughts?


Adam

REELAV8R

You could try running 1.5's on the intake.

I'm interested in the reasoning behind the greater lift on the intake but greater duration and less lift on the exhaust. Is it due to the heads in use?
It does make the accleration on the intake valve very high.

I agree with gkull a good 150# on the seat. Since those valves installed are at 135# with max lift of .600 and you are going to lift them that high (max height) you may not have any more room to shim the spring to achieve 150# on the seat without hitting coil bind or too close to coil bind.
Different spring rates on the intakes may be an option for you. This of course would raise the over the nose pressure as well which would help with valve control in which case you may be able to get to your 6300 or higher without float. Making the hydraulic lifters the limiting factor.

REELAV8R

This article may be of interest to you.

http://www.engineprofessional.com/TB/EPQ215_18-38.pdf

NewbVetteGuy

I didn't design, nor grind the cam so I can't really answer that question, BUT I have noticed a lot of high-end cam designers doing exactly this and having lower lifts on the exhaust side.

I think the insane pressures in the exhaust and the generally far smaller port sizes mean that more lift just isn't necessary; I see lots of dual profile cams with longer durations but less lift on the exhaust side.


At my lift, the heads have a 78% Intake to Exhaust CFM ratio, for what that's worth.


Adam

NewbVetteGuy

I don't really understand "installed height"; if I go with a different spring, like say an appropriate CompCams Beehive as Gkull recommended, how can I install a spring at a different "installed height"? -Isn't the installed height dependant upon the length of the valve and the location of the indentation for the valve locks? (My current springs are installed as high as they can go with the valve all the way closed.)

Is it possible to go with a spring that provides more pressure at the current height but doesn't get into coil bind as soon? (By going with a thinner or tapered spring-ala Beehive??!?)



"Installed Spring Height" doesn't seem like something that can be changed to me without changing valves; is that correct?


Adam

REELAV8R

The installed height is the distance between the base of the spring and the bottom of the retainer (top of top coil)
This distance can be changed by shims on the bottom to the spring which also changes the pressure on the seat and over the nose.

Read the article I linked. It explains it pretty well.

gkull

I can't find my pictures of measuring installed height with a digital caliper. You use the slider rod that sticks out the bottom end to measure from on top of the spring shim to the bottom of the retainer.

So you need to measure how the heads are set up now. If you have a bunch of shim on the bottom of the spring figure out the thickness.

I generally use tool steel light weight retainers. You can buy them or any retainer for that matter in increments 0, +.050, and +.100 so in your case lets say that they are setup at an installed height of 1.800 inches and you want to install some beehive that require 1.900 to get the 146# closed pressure. Just install +.100 retainers

My motor has +.100 valve stems and +.100 retainers to get my .800 max lift springs with shims to an installed height of 2.050 to end up with 220# seat pressure. I'm lifting my valves .714 inches with a solid roller cam

NewbVetteGuy

That article was awesome! Answered so many questions that I had.

-It also highlighted the fact that my heads didn't come with valve seats; my springs in my heads are sitting directly on the aluminum head surface. ;-(


I'm really regretting buying pre-assembled heads... So far I've replaced the rocker studs and I'm starting to get the feeling that I'm going to be replacing the springs and retainers and buying valve seats.... *Sigh*



Adam

NewbVetteGuy

I'm going to talk to Mike Jones. If he recommends I get new springs, I'm going to go to Beehive (if he says it's ok) springs, the comp tool steel 10 degree retainers, and some valve spring seats as my heads don't have any seats currently... ;-(



Adam

NewbVetteGuy

It did explain it quite well. I get it now.


Adam

REELAV8R

Done right, pre-assembled heads are fine. Problem is it's not done right very often.
My Dart SHP's were a mess. I identified some of the issues prior to install but there were more hiding in the installed height and distance form coil bind at full open, as well as shallow spring pockets that caused me a lot of problems later on. It was a good learning experience for sure, just expensive and time consuming.
Don't ever trust that a pre-assembled head was done right.

My AFR heads were done very well. I just shimmed up the spring for 150# on the seat. Everything else checked out good.

Old rule of "you get what you pay for" is still king most of the time.