Apparently i've been running the wrong valve springs. I have sportsman II heads, with 100# springs.

I guess with a roller cam you need like 125# ?

I've been experiencing some valve float at higher RPMS.

So what do you replace. Seals, springs, retainers, and locks?

-- Joe

 

Springs at a minimum, retainers and locks if they don't fit the replacement springs. If the seals are failing, replace them. If not, and they are fairly new, you can continue to use them if they don't interfere with the I.D. of the springs.

 

Hi Vader,

So a 100# spring is totally not enough for my setup with the roller cam eh?

Didn't realize that in 2000 when I put this together. Guess that explains the inconsistant behavior at 5000+ rpm that i've been trying to "tune out". haha

-- Joe

 

100 lbs of seat is definitly not enough for adequate valve control at higher RPM's. I'd look into a set of Comp's 986 or 987 or equivalents. Those seem to be the "generic" hydraulic roller spring that they recommend.

What is the installed height of your current setup?

 

This is all the info I have on the spec page:

Specifications:

Valves: 2.02 Int. Replacement part # 830605 (For –1 Heads, 4.911 overall length) 1.60 Exh. Replacement part # 830615 (For –1 Heads, 4.911 overall length)
2.02 Int. Replacement part # 830620 (For –2 Heads, 4.951 overall length) 1.60 Exh. Replacement part # 830635 (For –2 Heads, 4.951 overall length)
2.02 Int. Replacement part # 830640 (For –3 Heads, 5.015 overall length) 1.60 Exh. Replacement part # 830655 (For –3 Heads, 5.036 overall length)

Valve Locks: -1 & -2 Heads have 7 degree locks. Replacement part # 830305
-3 Heads have 10 degree locks. Replacement part # 830310

Valve Seals: -1 & -2 Heads use a Nitril seal. Replacement part # 830405 -3 Heads use a P.C. seal. Replacement part # 830410

Valve Springs & Retainers: -1 Heads use a 1.250 diameter spring. Seat pressure 100 lbs. @ 1.825 Replacement part # 830105. Retainer part # 830205
-2 Heads use a 1.440 diameter spring. Seat pressure 125 lbs. @ 1.825 Replacement part # 830110. Retainer part # 830220
-3 Heads use a 1.550 diameter spring. Seat pressure 200 lbs. @ 1.950 Replacement part # 830115. Retainer part # 830230

Pushrod Guide Plates: Replacement part # 830450. Note: Hardened pushrods MUST be used with guideplates. The guideplates MUST be adjusted to obtain proper rocker tip to valve tip alignment. For additional info regarding rocker tip alignment procedure, refer to World Products Tech Sheet WPP-TB1.

Pushrods: To obtain proper rocker arm geometry, pushrod length will need to be determined by using an adjustable checking pushrod. For info regarding on how to check for proper pushrod length, refer to World Products Tech Sheet WPP-TB1.

Rocker Arms: Sportsman II heads utilize a standard offset rocker designed for the Small Block Chevy.

Special Note: When using rocker arms greater than a 1.5 ratio, it may be necessary to elongate the pushrod guide holes in the cylinder head.

Rocker Arm Studs: -1 & -2 Cylinder heads use a 3/8 rocker arm stud. Replacement part # 830475
-3 Cylinder heads use a 7/16 rocker arm stud. Replacement part # 830480

Combustion Chamber Volume: 64 or 72 cc. See cylinder head part number list for chamber size.

Intake Runners: 200 cc

Head Bolts: ARP bolts134-3601

Head Studs: ARP studs 134-400

I have the "-1" head. Looks like the valve part # is different to.

-- Joe

 

Get springs to match the cam (what cam is it by the way?).

As a rule of thumb, i generally do not trust springs that come equipped from the manufacturer. I have seen too many stories of springs breaking on heads like Pro Topline, World, and even AFR. More names to avoid, K-motion (I've seen a few stories of those springs failing), GM springs (included with this category are the common "Z-28" springs you can find on ebay), or any other cheap knock off spring. For what the cost of springs are versus the cost of what happens if you break a spring or get the wrong one, it quickly justifies spending money on the correct spring. Isky, Comp, Crane, Crower, and Lunati are the only companies i buy springs from.

Also, do you have the means to mesure your installed height? The listing shows an installed height of 1.825", which is about 1/8" more than the "factory" 1.700" or so. For the optimal spring, you need to know the installed height (amongst other factors).

 

Hrmm. I can measure it with a dial caliper with the rocker off right? or no?

My cam is slp 51010, 224/230 .050 (280/288), .502/.510 lift, 112d lsa..

So. What would you recommend ?

Thanks!

-- Joe

 

That is where to take the installed height measurement. What is the diameter of the spring pocket?

 

Looking at their spring pacakges, roughly speaking, the -1 spring package is for sub-.500" lift, hydraulic flat tappet cams. The -2 is for solid flat tappets and street hyd rollers. The -3 package is for solid rollers.

Assuming you still have the stock valves, looks to me like the spring pockets in your -1 heads are probably machined to give about 1.750" installed height. The -2 and -3 heads are probably 1.800" and 1.835" respectively.

Basically, you bought the wrong head package for going with the cam you have. You really ought to have the -2 setup.

Look at your spring pockets, and see if they're large enough diameter for 1.45" OD springs. If tehy are, get yourself a set of Comp 987 or Crower 68390X3 springs, set up at an installed height of 1.780-1.800". Use the right retainers to go with them, preferably 10° ones; use a spring steel shim under them, such as you can get from Comp or Manley, to keep the springs from digging into the head; and use offset keepers to get the installed height you need.

It is very difficult to measure installed height with calipers. I would not trust that method. You could maybe get away with a snap gauge and a mic or caliper, if your snap gauge was small enough diameter. The right tool is a spring height micrometer.

 

Hrm.. Well. I was thinking of yanking them off and having them flat milled .039, to bring the compression ratio with my flat tops from 8.96:1 to 9.5:1, then replacing the springs.

Should I just unload the heads on ebay, and pickup a set of L98 vette heads, and replace the springs as outlined in This thread: https://www.thirdgen.org/techbb2/sho...threadid=47463


I ran these heads from 2000 until now. Got a bunch of runs in but always had problems in upper RPMs. tried tuning the problem out. I didn't realize there was a difference in springs for various cams. duh.

-- Joe
-- Joe

 

Keep the heads you have, get tehm machined as necessary, and have the racing specialty machine shop that you will be using for this, install the springs at the correct height while you're getting them milled.

I would not recommend downgrading to stock heads and then spending a bunch of money on working those over. That's backwards. You'll be spending extra money to make your car slower. {RB makes the gesture of sticking a pistol down the front of his pants and pulling the trigger.... ooops, missed one, better put a bullet over on the other side too....}

 

Ouch. RB, i think you would regret that move in the long run... (but so would he if he does the swapping of cyl. heads, so i see the point). But did it have to be so....dramatic? Isn't going right to ones manhood like that a bit...much?

I agree with RB, though. Do not get rid of the heads. It would be like you are taking a step backwards, and then tripping and falling flat on your bottom end when you sink lots of money to make them up to snuff with what you want to do.

But the 987 shimmed with offset locks/retainers (if needed) to a 1.800" installed height is just about right. THe 986 spring seems to be more of a spring that is geared for factory setups/installed heights. Whereas the 987 seems to be more of a spring for those who want to fine tune the seat pressures. Both would work, but have their time and place. The 987 (or 986, for that matter) ar roughly $85 at Summit or Jegs, IIRC.

 

Thanks a bunch for the responses!

I talked to my machinest today. He said he could mill my heads, but he thought it would be abad idea. He said to fix the spring ordeal first. he said it might not float just above 5k. He said with my high pressure oil pump, it could technically float anywhere. Especially on cold idle.

He also said I prolly ruined the springs I have.

Thanks again!

-- Joe

 

Hey guys,

So I need:

CCA-987-16 for springs
I can't seem to find a retainer/lock thats 1.430" from Comp.
Any hint on a part number there?

Now these springs are rated at

* Outside diameter: 1.430 in. two spring
* Inside diameter: .697 in.
* Seat load: 121 lbs. at 1.800 in.
* Open load: 388 lbs. at 1.200 in.
* Coil bind: 1.150 in.
* Rate: 344 lbs.

So, if I'm understanding this. I'll just need 10d retainers/locks, and some shims under the springs. like .050 shims or ?

I'm kinda new with heads/springs stuff. Never wandered that way.

Thanks a bunch

-- Joe

 

740-16 are the recommended retainers by Comp and 611-16 are the locks. This gives you a factory isntalled height of whatever you have now. They have +.050" locks and retainers if you need to increase your installed height. You may or may not need them, depending on the height you have now.

I don't know your installed height, so i will just toss out: don't shim it more than you have to.

 

Awesome. SO. These springs as is with the retainers and locks (and no shims) are a 1.800 installed height. If my setup is say 1.850, then I need a .050 shim under it, and a lock/retainer thats +.050. But if my installed height currently is 1.750, what do I do?

More importantly, If I just put them in w/out shims and change the installed height to 1.800, what would that effect?


Here is the specs from my card that came with the heads:

Max spring seat depth (from inside step) .030"
Max spring diameter (use 1.635" cutter) 1.625"


Thanks!

-- Joe

 

I asked about the diameter, and installed height. Heres what I was given.

Yes you can put that spring on that head dash - 1 head has installed hgt of
1.835" 100#
Have a great day!


So I'm assuming I can go ahead and order these three part numbers:

CCA-987-16 springs
CCA-740-16 retainers
CCA-611-16 locks

What about shims?

Thanks guys!

 

CCA-4754 shim assortment

 

Okie. So try an .030 first and see how it works?

Sounds good.

Thanks a bunch guys!

-- Joe

 

If your heads are 1.830", and you want 1.750" installed height, you need .080" of shim.... I'd suggest a .015" against the head and a .060" on top of that. That's mighty close to what you need.

After you put them on, rotate the engine by hand, and check a couple of intakes and a couple of exhausts at their fully open points, to make sure there's some gap between all their adjacent coils. Look for at least .030".

 

I would hand rotate it twice to check for binding and what not on every spring. I'd rather discover a problem now than find out the hard way. But perhaps that's just me and I'm being paranoid.

 

I thought I wanted an installed height of 1.835 to match my current installed height?

Now i'm confused again.

-- Joe

 

Your current installed height doesn't matter. Its only value is that it conveniently tells us how much space there is between a retainer and the head, so you have a starting point for setting your new installed height.

You are looking to set the installed height to what your new springs require, not to match your old height.

 

Oh.. I see. So your saying that requirement, entails a .15 on the bottom and a .60 on the top under the retainer?

I dig. Then check it with a feeler. If I have at least .030 between springs at max lift, i'm golden?


Thank you. You've been most helpful.

-- Joe

 

That's it.