crazy3rdgen

iTrader: (1)

I'm shooting for 450 hp at the crank, will this set up get me there?

HEAD WORK

Cutting the guide OD to .530",
so I can use the Teflon valve guide seals.
getting the stock pull-out studs pulled out, and the holes milled & drilled & tapped for screw-in studs;useing good quality studs, and guide plates.

Carb

750=400 $


Crank

Scat 9000 Crankshaft 350 Chevy Chevrolet =200$


Cam

Chevy 262-400 Xtreme Energy XR282HR Cam=353.07$


Rockers

Comp 1302 1.6 roller rockers=265.69$


Valves

Manley "Street Flow" valves, with undercut heads=200$


Intake

Rpm Airgap=300$

Token

cut to 530? you can't fit 1.6 rockers on that then... the cam lifts to .550 with 1.6s

crazy3rdgen

iTrader: (1)

no O.d .530 is good and the depth for the guide will be cut for .6 to deal with the .51 lift of the cam with the 1.6 rockers.


Anyone have any clue what she will be pushing????

thirdgen88

More than likely the valve...

Sorry...

crazy3rdgen

iTrader: (1)

huh???

RB83L69

And these heads would be...... ??

crazy3rdgen

iTrader: (1)

Lol rb you don't remember me from that big post alittle back.

But their vortec's

crazy3rdgen

iTrader: (1)

ttt

RB83L69

No, sorry, I don't remember; I've probably slept since then, and most likely had to be completely re-trained a couple of times besides.

Looks like it should at least get close; 425 HP or more, I'd guess.

I'd suggest getting 1.45" OD valve springs (or even 1.55" if possible which I don't know about on those heads, that would be basically some mild big-block ones, if you could find some that give comparable pressures to what the cam mfr calls for with that cam which is 125-140 on the seat and 360-375 on the nose), and maybe a rev kit; anything you can do that will stabilize the valve train at higher RPMs, will pay off, up to the point that the hydraulic aspect of the lifters and their weight become problems. You should be able to get your peak HP to occur at a little over 6000 RPM, maybe 6200, if you can keep the valves from floating.

crazy3rdgen

iTrader: (1)

How did you find that out

"mfr calls for with that cam which is 125-140 on the seat and 360-375 on the nose"

I'm looking in the summit mag right now for some valve springs, there's like, Single outer valve springs, Dual valve springs ect=me confused there.

And when you mean nose is that the same thing as "open pressure"-i think it is.

RB83L69

Experience; and looking at the mfr's catalog, and working out the behavior of their recommended springs. Both the "base model" ones and the "premium" ones. You'll find similar spring specs from any of the top-line cam mfrs for cams in that "bracket", not just Comp; look at Crane, Crower, Isky, or Lunati for comparison.

Although, you'll find that in general, those spring numbers will work well for almost any aggresive street cam design; flat or roller, hydraulic or solid. Although, I would consider them to be the bare minimum for a solid roller of any intended use. And, you can use more pressure if you use a billet cam core, at the expense of trading off a little seat and valve life.

"Nose" is the word for the peak of the lobe; full open.

crazy3rdgen

iTrader: (1)

Single outer valve springs, Dual valve springs ect= ya missed that RB , why are they different

RB83L69

http://www.compcams.com/Technical/Cu...ML/324-328.asp

http://www.crower.com/pdf/105-146.pdf go down to about page 132

http://www.cranecams.com/index.php?s...s&lvl=2&prt=32

etc.

crazy3rdgen

iTrader: (1)

ohhh ok i got ya, damn dude you deserve to be a mod for the tech/engine you know way too much helpfull info to go to waste : ). But as for my valvetrain

I'm thinking of getting the max- seat/open i can get valve springs, for this cam, as you said for those higher rpms. So now i been looking for the perfect ones and this is what i found. Thank goodness i have the summit catalog cause its not showing the valve springs specs on the site .


CRN-99890-16 their dual spring

O.D/I.D 1.530/1.116
SEAT LBS/INCH 130/1.875
OPEN LBS/INCH 370/1.250
COIL BIND 1.160
SPRING RATE LBS 384

Now i know i have to see if the o.d will work on these vortec heads but, do these look like real good springs for the set up.

RB83L69

Yes; except for one possibility: those are 1.530" OD, which is QUITE A BIT larger than stock. Check with yoru machinist and make sure the heads can have their spring pockets cut out that far. Not all stock heads can go there without hitting water.

If not, look at the Comp 987 or Crower 68390X3. Those are both about 1.45" OD.

crazy3rdgen

iTrader: (1)

hey Rb look at this i went to both sites on the valve springs you suggested that we know will work on these heads and crower didn't give me all the specs here look. Such as the seat and open, Cause i wanted to see what was the better of the 2

Apeiron

Figure out your installed and compressed heights, and look up the spring pressures on the chart.

crazy3rdgen

iTrader: (1)

I'm 17 learnin my *** off here, bare with me

RB83L69

They're real close.

Both are dual springs w/damper.The Comp rates itself at 121 lbs @ 1.800" installed, 388 lbs @ 1.200" (.600" lift from 1.800" installed), coil bind at 1.150" (.650" lift). The Crower is 116 lbs @ 1.800", 389 lbs @1.200", bind at 1.110".

The question becomes, can you get 1.800" of installed height on your heads, with your valves, after cutting the pocket out from 1.25" to 1.45". The problem you may run into, is that you might not be able to cut the pocket to full depth and to that diameter, at the same time, without hitting water. With stock heads, there's no guarantee of being able to get more than 1.700" of installed height with stock length valves and that size spring pocket. Sometimes you can, sometimes you scrap a head casting trying.

So you might have to use less installed height, which will lower your max lift and increase the seat pressure. That cam and those rockers will put you to about .555" peak lift. So, either spring will get you there, AS LONG AS your machinist can get an installed height of 1.750" or more. Any less than that, disaster will occur. In that case stick with 1301 rockers which is the same thing except 1.52 ratio.

There are however several ways around the dilemma. You can get .050" offset keepers, which will give you .050" more installed height, or 1.750" on the stock depth spring seat. You can get longer than stock valves in some sizes, such as from Manley. http://www.manleyperformance.com/pdfs/valves.pdf The longer valves might not be available in the Street Flow series, you might have to step up to pricier valves before such things become an option. I can't remember which side (int or exh) you're more likely to have trouble; I think it's E, but I could be wrong.

So the spring choice will probably come down to price & availability; and whether or not this combo is even possible would need to be investigated. In any case the valve guides will have to be cut down, both their OD so that the springs can fit over them, and their height so that the retainers don't smack into them (another instant major ugly disaster).

crazy3rdgen

iTrader: (1)

total gross lift with those rockers, .51 x 1.6 =.816 gross lift


where are you getting .555

also.. So valve springs dont go by just o.d/i.d----open/seat lbs.

There all not the same height?

So 1.8 is the height of the spring in the seat? And theres 121 lbs pressure of tension on the retainer when installed.

Ok you know what RB If you honestly think i should sell these heads and go with a different set just be upfront. I'm not in any rush and the way i look at it. This is turning into a hassel. I am using this 282 hydr. roller cam. I'm serious on the head change if it would be for the better. I have plenty of time, the motor is getting built by me toward the end of summer but all the parts will be purchased as money rolls in.

Now i researched and it said in this mag that i shouldnt have too much spring load or too less. But just right so theres always tension on the rocker at full rpm range-less friction. So i guess the more tension isnt good.<~~ learnin

It just confuses me on how much to machine down in the guide seat. Well yeah its pretty obvious on the o.d. but i have no clue how to find out the depth.

Just don't seem right on a 1.6 rocker set up with this big of a cam doing it right using these heads.

Token

gross lift is already determined as .510
divide .51 by standard 1.5 ratio rockers and multiply that by 1.6 (you'd use) and you get .544

RB83L69

I wouldn't necessrily say "replace the heads"; only, have a healthy respect for their limitations, and for the possible pitfalls taht can cause distaster. You're basically tring to max them completely out as far as they'll go, and that's about the easiest way of tempting fate I know, to invite unexpected catastrophe. Which is not fun.

To get the lift, as said, divide the "spec" lift that the cam mfr gives for 1.5 (stock ratio) rockers, and multiply by your new ratio. The number you want in order to multiply by the new ratio is "lobe lift", which you can look up on Comp's site in the lobe listing; or obtain by division.

In the case of the XR282, the lobes are the 3315 intake and 3316 exhaust, with lobe lifts of .340" and .347" respectively; which when multiplied by 1.5, gives .510" & 520", and when multiplied by 1.6, gives .544" & .555".

The 1.800" spec is the height of the spring between the retainer and the seat, after it's been installed. Which is fine; except that stock valves in stock seats have a spec of 1.700". Somehow, in order to get that 1.8" number, something's got to change. If you don't do something about it, you'll put those springs on there, and they'll already be compressed .100" in effect, and you'll lose that much of their "spec" max lift (which means you'll be limited to about .450" max lift ... clearly inadequate), and gain seat pressure of about the spring rate (385-390 lbs per inch) times that "built-in lift" of .100", or around 35-40 lbs with either of those springs I listed. I can 100% guarantee that if you put either of those springs on those heads with stock valves at stock height, parts WILL break, lots of them, probably before you get all the way around the block the first time. And that my friend is a rude introduction to the engine you just built and lavished all your available time and money on.

You can't fix it by using 1.5 rockers; even with that, you're still well over the line, unless you get the springs set up properly.

This is why you see so much "Comp bashing" going on all over the Internet here lately..... those cams are MURDER on the rest of the valve train. They push the envelope of what the other parts can withstand. One mistake, and it all goes up in shrapnel. Lots and lots of people have trashed ALOT of valve trains with them. Do it right, and they'll give you more power than almost any other cams on the market, at any given level of "big cam penalty".

Incidentally, I own a XR282HR; I ran it in my 400 for a while, with the 987 springs set up at 1.800". I have .100" longer than stock valves in it to get the installed height. I'm running a XR264HR in my 305 at the moment, with .050" offset keepers and 987s, so I ended up with 1.750" of installed height, but less lift, so it all still fits. I have about 65,000 miles on the 2 cams, with no visible wear or any parts damage that I'm aware of. So I know that it can be done with those particular cams, and how to do it.

crazy3rdgen

iTrader: (1)

yeah i understand and am 100% sure that i don't want disaster and completely appreciate your time in making sure its not a distaster cause you have helped A LOT.. 100% SURE.

I should have mentioned it earlier but I plan to buy new and better parts for just about everything. Including the valves. So to determine how long of a valve I want I can maybe... take out one in the vortec head, measure it with an outside caliper dile then add .100 to it? I'm sure there's a way to tell without going that direction but i cant find specs on these vortec heads how they are stock right now. ERR!

I do have a book where they machined the valve pockets to take 2.05/1.6 combination. It says "chamber shrouding on both the intake and exhaust is minimized". But whatevers easier.

________________________________________________
It just confuses me on how much to machine down in the guide seat. Well yeah its pretty obvious on the o.d. but i have no clue how to find out the depth.
________________________________________________

For instance picture me going to the machine shop and I say, I need the guide seats cut down to be able to work with 1.8 valve springs. With an o.d of 1.45. Is that all they need to know? with that information are they able to know how much to cut the depth in the guide seat.

I may just have my dad drop a head off one day this week and ask the guy if he could experiment with the head and what he thinks. He may already know. hit me back when you get a chance

RB83L69

First: 2.05/1.6 has nothing to do with the springs. That's the valve seats. Don't worry about that part in relation to the springs.

Next: stock SBC valves, in Vortec heads or any others, are 4.911" long. That might save you a few steps.

Next: the rule of thumb on how far you can go with valve spring pockets, is that there is no rule of thumb. It's determined entriely by how thick the casting is around the pocket. Look at your heads; you'll see that the pocket is sort of surrounded by raised portions of metal; now imagine that the metal is only .100" thick. Or, that the heads have a slight core shift. You can only cut just so far before you go through the metal. There's a "sort of" rule of thumb; and that is, people will usually assume that it's safe to cut to a depth .030" above (not all the way down to) the stock pocket, to a diameter of 1.45". Ask your machinist what he feels safe doing to your particular castings. Each casting # is a little different, and individual heads vary considerably in how far you can go before scrapping it.

crazy3rdgen

iTrader: (1)

It just confuses me on how much to machine down in the guide seat. Well yeah its pretty obvious on the o.d. but i have no clue how to find out the depth.
__________________________________________________________

your answer:


there is no rule of thumb. It's determined entriely by how thick the casting is around the pocket.
___________________

How is that so? because they all have to have the same spring load installed.. So what your sayen is they keep machining untill their for sure the spring will fit? Like with a micrometer they stick in the seat that tells if it hits coil bind or if the rocker smacks retainer? There has to be a precise way.

sorry if i didn't word this good but i gotta go to work , be back at like 9. later

crazy3rdgen

iTrader: (1)

omg it finally paid off. Rb check it out!!!! they even used the same cam as me!!!

http://www.chevyhiperformance.com/te...148_0208_vort/

crazy3rdgen

iTrader: (1)

i wonder about this spring

Comp Cams recommends that its PN 986 double valvespring be used with its XE 282HR camshaft. The Comp Cams PN 986 >> valvespring features an installed height of 1.750 inches, a 1.430-inch od, 0.697-inch id, and a seat pressure of 132 pounds.

132@ 1.750 & 280 @ 1.250 much smaller then the other 2...

RB83L69

Well, there you go; now you know what to do. Too easy. It's always good to know that somebody else has done the exact same thing and got the desired results, that way you don't have to take on quite so much risk.

The 986 & 987 have similar dimensions. What works for setting heads up one, will work the same for the other.

With the 1.6 rockers, it will be right at the hairy edge of the 986's capabilities. I believe I'd step up to the 987 for that combo.

Looks like those heads don't feature quite as much of a "hump" around the spring pocket as some others do. Alot of heads, when you go to enlarge the pocket, you're not cutting straight down into the casting; instead, the cutter is cutting outwards, into this raised portion of the water jacket right there. When you do that, the casting gets REAL THIN, REAL FAST. Looks like those heads are flatter right there though, so it won't be near as much of a problem.

Take a look at these. These are some REALLY OLD (461 I think) castings. Look at what's going to happen if you start cutting those pockets. Remember that the casting isn't real thick right there around those pockets. Compare that, to how flat on top the heads in the article are.

crazy3rdgen

iTrader: (1)

oh ok, I see. My heads are the newer ones. Look exact to the ones in that article. I'll go with the 987's.

Let me get this straight with the guide seat depth! Is it determined by using the valves I will use with my set up?

For instance, they take a micrometer after they machine alittle bit, put the valve in and see how it lines up? Rb help me on this if you can please so I understand how i should approach this guy. So I know how it works. I tried to research on it and am confused on how they get each valve spring at a perfect install height. And all that.

crazy3rdgen

iTrader: (1)

my vortecs

RB83L69

What they do, is to cut the seats to all the same depth, usually based on the factory cut. Maybe they'll take it to the full factory cut depth, maybe .050" more, maybe .030" less, it will be whatever the machinist feels comfortable with. I'm guessing they'll go at least as deep as the factory and maybe more. Then, to set the actual installed height, they'll use a spring mic like the one in the article, and stack shims under the springs.

You can always add more shims, to decrease the installed height. You can use longer valves (if they're available or economical), offset keepers, or a deeper cut, to increase the installed height. Most machinists will want to have plenty of room to add shims after all machine work is done, and will select parts accordingly.

The thing about using a deeper cut, is that once you hit water, the head is trash. You can't "undo" that very easily (cheaply). It usually costs about 1 to 1½ hours labor to weld up and re-cut a pocket; that's $75-125 in labor; a head core is often cheaper. But it looks like, if they cut to the factory depth, that won't be a problem; and they might be able to go .050" deeper. With that, plus .050" offset keepers, they should be able to get the installed height to at least 1.800", even with stock length valves. That's plenty of room to be able to shim up any of those springs correctly.

crazy3rdgen

iTrader: (1)

.oh ok i got ya. Rb now i just hit a wall.. There's always somthing. Check this out.

"The easiest way to identify a Vortec head is by the sawtooth pattern cast into the front. Look for casting number 12558062, but avoid casting number 10239906, which has a modified exhaust seat and loses 20 percent of its flow at 0.120-inch lift"

Cited from this article

http://chevyhiperformance.com/howto/97458/



well i tried to put the pic on here of my head casting number but pics arent working right now but it has a 10239906 casting #

crazy3rdgen

iTrader: (1)

"the heads you want to stay away from are the 906 castings that came off heavy duty trucks, the exhaust seats restrict flow"

"I do a lot of those head and yes stay away from the 906 heads.They have ex. seat inserts that don't help flow.Unless you are going to 1.600 valve and some porting."

RB83L69

They later published a retraction of that remark.

No one else has observed that since.

I think you should proceed with your plan.

crazy3rdgen

iTrader: (1)

alright , so I guess i wont pay attention to that. Just do what i gotta do and see what comes out of it.

crazy3rdgen

iTrader: (1)

You can always add more shims, to decrease the installed height. How does that work. Cause if you think about it, adding shims would create the spring to go up more? causing the installed height lbs to be greater? <~~ confused

RB83L69

The retainer is some fixed distance above the head; as determined by valve length, the retainer itself, and the keepers. Putting shims under the spring uses up some of that space and leaves less for the spring.

That's why the goal of all this is to pick springs that match what the cam needs; then pick valves, retainers, keepers, and machine work that will give a little extra height beyond what the spirng's specs call for; and use shims to set the height to the correct value for the application.

Yes, all the spring pressures will go up as shims are added. And "max lift" available will go down; as adding shims uses up some of that too.

crazy3rdgen

iTrader: (1)

OH ok, I totally understand you . THanks man. I'm going to get the information together tomorrow to see everything i'm working with as like a refresh of the memory.

crazy3rdgen

iTrader: (1)

Head Work

•Port the bowl area and exhaust ports, do not touch the intake ports.

•Stock studs pulled out, then milled, drilled & tapped for screw-in studs.

•Guides cut for comp 987 dual valve springs, (Specs- O.d 1.430/ i.d .697) (121@1.800 installed seat load) (Open load 388@1.200) (Coil Bind 1.150) (Rate Lbs/In. 1.150) (Titanium Retainer 730) (Steel Retainer 740) (Shims 4754)

•Pushrod Holes opened to ½ inch


Just let me know if there was something I missed. Now Do you think i should get all of my valvetrain purchased before i send these heads to him? Cause dont they have to use the valves I'm using and make sure the springs pressures are all the same/add shims. I don't think I could add the shims and tell all the lbs pressure myself on the build up. Just cause i don't have those kind of tools. what do you think?

crazy3rdgen

iTrader: (1)

.

crazy3rdgen

iTrader: (1)

rb

crazy3rdgen

iTrader: (1)

does that sound good?

RB83L69

That should work; as long as the machine shop can get enough installed height out of it. At worst you might have to use the offset keepers.

crazy3rdgen

iTrader: (1)

Do you think i should get all of my valvetrain purchased before i send these heads to him? Cause dont they have to use the valves I'm using and make sure the springs pressures are all the same/add shims. I don't think I could add the shims and tell all the lbs pressure myself on the build up. Just cause i don't have those kind of tools. what do you think?

RB83L69

Buy everything you need; get 2 sets of keepers, one standard (613) and one offset (614). Send the ones you don't use back for creidt, or sell them.

crazy3rdgen

iTrader: (1)

ok keepers??? Refresh my memory. What are keepers, where do they go.

RB83L69

They go down in the retainer, around the valve stem; and hold the retainer on the valve. The offset ones let the retainer sit .050" higher up on the stem. Comp calls them "valve locks" for some reason.

crazy3rdgen

iTrader: (1)

why would i need offsets if i get longer and better valves?

RB83L69

If you do end up with longer valves, then you most likely won't need the offset keepers too.

crazy3rdgen

iTrader: (1)

stock SBC valves, in Vortec heads or any others, are 4.911" long

so what should i go with for 121@1.800 installed

I'm looking in summit and their exhaust/intake say

intake 2.020 , .100 longer. How are these valves specs given by these low numbers. 2.020 can't be the length.

And are the intake/exhaust going to be the same length. This is like the last thing we have to figure out. thanks for bein there on the valve train help!