If the sportsman-II heads I have, have an installed height of 1.750" (as indicated in the card) , and I re-spring with comp 987, which is a 1.750" installed height (right?) , then I won't need any shims at all, Right?

What do you all think of Chrome Moly retainers, vs steel?

-- Joe

 

987 springs are rated at listed at 1.800". Shim them to 1.75"

 

[Ugg. your right I was looking at the wrong column on the table.

So a .050 between spring and head eh? That would bring the seat pressure from 121lbs to 138lbs at that installed height.

So then with my .510 lift cam, i'll have an open pressure at max lift of around 310lbs. That sound ok for hydraulic roller cam?
(My cam is SLP-51010 which is basicly Comp XR276HR.

Any word on the moly retainers?

-- Joe

 

The retainers? Comp's "steel" retainers? They are 4140 chromemoly.

Pressures look good.

 

I need to find a way to measure mine. My papers that came with the heads back in 1999 say installed height of 1.750" and seat pressure of 100lbs there.

But when I emailed World Products the guy said, install height of 1.835" and seat pressure of 100lbs there.

So. I dunno!

If mine are 1.750, I put a .050 shim on the BOTTOM under the spring. If mine are 1.835, I put a 30 and a 5 on the TOP, right?


-- Joe

 

Installed height = the space between the bottom of the retainer, and the top of the spring pocket and associated hardware

You don't ever put shims on top of the spring. They ONLY go under the spring.

If you take a spring that's rated at a given installed height, let's use the #s in question and say 1.800", and you install it a a height of .050" less than that (1.750"), you have done 2 things:
1. Increased the seat pressure and open pressure, by the spring rate x .05"; and
2. Reduced the "max lift" available with that spring, by .050".

The paperwork that came with your heads in 99, tells you the installed height OF THE SPRINGS THAT WERE ON THEM AT THE TIME, not the construction of the heads themselves. If the heads are still built exactly like they were in 99, you can look at the shims that were supplied with them, and figure out what the available height was then. For instance, if the sheet says the springs had an installed height of 1.75", and you look at the heads and see that they had a spring cup that's .030" thick and a .060" shim, then the heads have that 1.75", plus .090", available. So, when you go to put those 987s on there, and you want to set them up for their correct spec of 1.800", you'd use the .030" spring cup and a .010" shim underneath that.

If there's no shims at all, or at least nothing you can leave out, then the only ways to get the additional installed height that you need with the spring change, are to use longer valves, or offset keepers, or by machining the heads.

Keep in mind that wear on the seats and doing valve jobs, increases the installed height, by allowing the valves to move upward in the guides.

You need 1.800" installed height with the 987s and that cam. Sounds like your heads came with stock-size springs besides; and that means stock-size retainers and cups and shims and so forth; so you need the right size all of those parts too.

If you don't know and/or cant figure out and/or don't have the tools to measure installed height, take them to a racing machine shop (NOT the corner parts store, unless that guy builds motors for racers) and get them to measure and set them up for you. It's too important to leave to chance and guesswork.

 

Ok. So I measure mine from the bottom of the retainer, to the bottom of the pocket. Say my spring is 1.750, and a .050 shim under it. The installed height of the spring is 1.750, but the height of the pocket to retainer is actually 1.800. So I'd leave out the .050 shim to get an installed height of 1.800 with the new '987s.

But if my pocket to retainer is only 1.750, then i'd need ofset lockers to get the .050 back to make a 1.800" install height?

So its really a matter of how much my pocket is machined vs valve height. I want the spring to be 1.800", and I make up any difference with a shim if the distance is larger? I think I get it now.

But if the distance is shorter, sya 1.750" you don't recommend running the Comp 987 at 1.750", because you think it might coil bind with my lift (.510). ??


-- Joe

 

Yup, that's the general idea.

But, don't forget, your heads are aluminum, so the springs will wear into them if they sit directly on the casting; and also, if the pockets are cut to a bigger diameter than your new springs, there's nothing to keep the spring from "walking" around on the head. You NEED something on top of the head; a shim (preferably one of the hardened spring steel ones like from Comp or Manley, not the parts-store variety) if the springs fit tight in the pockets, or a seat cup/locator if not.

Yes, I would not run those springs at less than their "spec" installed height. But, since you're buying retainers and keepers anyway, if it turns out that you don't have enough space in there after you put in the minimum hardware required, just get .050" offset keepers. That should give you enough room. If not, you'll need to buy longer valves. That probably won't be necessary.

 

Hi. The Sportsman-II are cast iron heads.

The springs are 1.250 in there right now. I should take a valve cover off tonight and measure the spring pocket. I hope its big enough. If its only for 1.250 heads (and car is together). Can I get a 1.250" spring comparable to the 987 ?

I imagine they wouldn't machine the pocket greater than the springs in it, so I might be screwed anyway..

Thanks for the help guys on the math. I understand now. At first it was messing me up..

 

I would expect them to have larger spring pockets, their online catalog says 1.550". If you have the room, use it. If you do use the 987's I would toss a locator on there to center the spring.

Here's the 987 spec @ 1.750 installed:

1.750" installed - 1.150" coil bind - .060" safety margin = .540"

The biggest issue is the increased pressure, like RB pointed oit.

 

Okie. I'm going to take one of my springs out today, and measure the pocket, spring diameter, and installed height using Comp's method on their website.

I'll relay back the information thanks

 

OK I borrowed the tool from a machinest buddy. Here is the specs:

Install height of current springs (NO shims were there).

1.765" from the BOTTOM pocket. The bottom pocket is 1.25" wide.

There is a top pocket machined out, I guess for larger springs. It is .040" higher up than the bottom pocket, and measures 1.54"

The install height from the wider pocket is 1.725"

The retainer is .094" thick.

Soooo.. It appears to use a comp 987 in the upper pocket, i'd need an offset keeper to make up .075". I'm assuming the way it works is the keeper allows the retainer to move upward more?

Thanks guys.

-- Joe

 

I have never seen a .075" offset keeper or retainer for that matter, just .050". And the side of the keeper that locks to the retainer is unchanged. Tehy get the +/- .050" from moving the notch that locks into the groove of the valve stem up or down.

As for the 2 seperate spring seats, My guess is to accomodate 2 different springs without having to remachine the head or having to use cups/locators. Keep in mind, there are a few different spring packages, ranging from the 1.26" springs to the solid roller springs that are 1.55". Either way, i would still use a cup or locator as the 987 is a 1.43" OD.

Retainer thickness doesn't affect how the installed height, only the bottom of the retainer does (And the bottom of the center part, for the guide boss-retainer clearance).

 

So if I use a 614-16 +.050" lock, that puts me at 1.775" installed height. That puts me at 130lbs @ seat, and a hair over 300lbs open. (1.265"). That leaves me with over .100" safety margin.

The problem with the locator is, they are .060" thick.

-- Joe

 

You may have to buy .100" longer valves then.

Manley 10751-8 Exh & 10752-8 Int

Next time you buy a new set of heads, remember, it's alot cheaper to include these options at that time, than to go back and retrfit them in later. Always buy them with the next step up of springs and hardware than you think you need now.

You might want to contact World and see what they say; maybe they can tell you what they do in order to use those springs.

 

They said I needed there roller cam springs, .040" longer valves, etc.

I might just unload the heads this fall and get something better. Not really sure yet.

If my current springs don't bind at max lift, and have plenty of room, would a small shim increase the pressure enough to get me by until I tear down the motor? I'm getting inconsistant "once and a while" valve float around 5500rpm cuz the springs are for hydraulic flat tapet, rather than roller.

-- Joe

 

They are flat tappet springs, not roller. Valve float, I'm not suprised.

Yes. Shims decrease the installed height by compessing the coil by whatever amount the shims are, So yes, pressures to increase.

Just curious, with the current setup, how much space do you have between the guide boss and the bottom of the retainer?

 

Not sure. I'll go measure it in a few mins.

I got some '987s.. They don't work. The guide boss is machined to stock diameter, so the center spring won't seat. Infact, it won't slide over the guide boss at all.

I got the '987s at cost from a friend, so I'm not complaning. I guess I'll throw them on ebay.

I'm gonna toss a .015" shim under mine, and run it til the end of the season. World says my spring rate is 300lbs.

If I recall, '986's require a .0530 guide boss as well, correct?

Guess I'm screwed for now..

 

Both the 987's and the 986's are the exact same diameter on the inside and outside. That means both have the 1.43" OD and the .697" ID. You just need a spring with a larger ID. They are also both dual springs with damper coil, which gives them basically 3 layers. Try looking for a stiffer outer spring and a inner damper for it.

If you are flexible on the OD, a personal favorite for me spring wise is the Isky 235-D spring:

O/D: 1.26"
I/D: .886"
Seat pressure: 130 lbs @ 1.750"
Open Pressure: 320 lbs @ 1.200
Spring Rate: 350 lbs/in
Coil Bind: 1.150"

Just because Comp doesn't have springs, doesn't mean anyone else won't.

 

That doesn't sound right.... the inner diameter of both of those spring part #s is .697". I use them all the time over Teflon seals installed over .530" guides. I can't believe your guides are .700" or larger; not even stock guide bosses are that big. Last time I looked at some of those heads, they were .530" IIRC.

What seals have you got on them?

 

Hey,

The top part of the guide boss is .530. It fits a stock positive seal. I tried some clevite seals for example, that are labeled for a 4.3.. The inner spring actually does fit over that seal fine.

The problem is the boss then tapers OUT to about .700 on its way down to the spring pocket. So even though the spring will fit over the positive seal, it bottoms out about a half inch from the spring pocket.


-- Joe

 

That gives .050" safety margin. Think thats ok? (.510 lift cam).

My pockets are 1.765" now, but I ordered some .015" shims to make a std 1.750" install height. Then if I need 1.800", i'll go with a +.050 keeper (which I have in 10` at the momment).

1.765" is a weird install height, don't ya think? But I measured it twice..

-- Joe

 

Two of my stock sportsman springs had broken inner coils.

As soon as I can find someone to buy my comp 987s, i'll order the Isky springs. They'll work find with my .015 spacer (which will make a 1.750" install height).

Thanks..

-- Joe

 

For the Isky springs, at the installed height, you have about .540" to play around with, after the safety clearance. (some may argue more or less, though usually maybe a tad less, for safety clearances)

1.750" - 1.150" - .060" = .540"