dimented24x7

iTrader: (2)

Anyone know offhand what the valve spring rate for the base line GMPP vortec heads? Is it around 270 lbs/in? More? I put in an isky 262/270H (208/216 .435/.445), and they recommend using a stock type spring with a rate of 310 lbs/in. This doesnt seem too far away from a stock spring, so Im sort of curious what came with the GMPP heads. If its close, its a moot point to replace the springs. On the other hand, even though I have no buisness revving over 5k, Id still like to have the slight upgrade if the current spring rate is lower.

dimented24x7

iTrader: (2)

Seat/open pressures will also work if someone has them. Also, IIRC, the springs in the vortecs are odd OD/ID dimensions as well, coorect? So possible machining could be needed to the seats if I chose to replace them?

dimented24x7

iTrader: (2)

PN 10212811 1.25" diameter
80# @ 1.70"
Solid height: 1.20"
Rate: 256 lbs/in.

I think those are the ones the base heads came with (barf...). These are also the same ones listed for the 330 HO in GMs service liturature. I would assume that if they worked for the 330 HO cam, then they should work for my stone age flat tappet.

Sonix

iTrader: (1)

Wow, those are some weener springs right there. zzzzzz (sleeping)
But 1.25" od, so any normal 1.25" OD spring should fit.
I've heard vortecs have a wider valve boss, do these springs have the "normal" ID? (I'm not sure offhand what that is for 1.25" springs).

Do you know what yours are set up at? 1.7"? .500" max lift, so you've got the nice .050" safety margin there, but 80# seat is pretty sad. And unfortunately you can't shim them. That's about 200lbs open force. Ouch.

Comp 981's should drop right in (if you can confirm the ID of your current springs). You can shim them up since you've got only .450" lift, and get a bit more force too. Budget $100 when the smoke clears.

Your cam isn't exactly "lame", 262/270 and 208/216 is decent. It's not Xtreme energy range, but it's certainly not sleepy stock cam range.

dimented24x7

iTrader: (2)

Your probably right in that Ill jsut have to drop in better springs. The 330 HO cam has a fairly lazy profile on the intake, probably to help the weenie little springs control the heavier intake valves, not to mention that it probably has alot of advertised duration. Isky recommends the 205-D spring with this cam, which by my calcs, will provide an additional 20 lbs of open pressure. Still doesnt seem like a whole lot but thats what they recommend.

Sonix

iTrader: (1)

Yea, 100/300 is the norm for open/nose spring force for a 1.25" spring. You've got 80/200lbs. The 200lbs is the point of interest, which would give valve float at a low RPM

dimented24x7

iTrader: (2)

Tomorrow Ill have to take some measurements and esimate teh ID of the springs there. The vortecs do ahve huge valve guides to retain teh positive seal. Those may be hard to clear.

dimented24x7

iTrader: (2)

Hmm... with the recommended shim itll be about 100/245. I wonder what the max force the pressed in studs can take? Dont mind replacing them, but I hate doing work on a motor that generates lots of metal filings.

Sonix

iTrader: (1)

You're thinking about shimming the current springs? I wouldn't.
1.70" installed - 1.2" coil bind is only .500" lift. Give .050" for safety and you're right where your cam lift is. You can't really use much shim (I wouldn't use any).

I'd use a .600" max lift spring (like I said, comp981's or equivalent), that have a 1.8" installed height and 100lbs at 1.8". Then shim it up about .050" or so.
Hydraulic lifters can take 350lbs on the nose without collapsing.

You could pull and tap the studs, but i'd suggest pulling the intake manifold and headers so you could hold a vacuum in the ports while tapping.
I think i'd rather just pin the studs. I'd stuff paper towels in the drain ports, pin all the studs then vacuum up the filings and pull out the paper towels.

Easy breezy.
IMHO at least

dimented24x7

iTrader: (2)

Those numbers are roughly what I would have with my cam and iskys recommended spring/shim combo.

The listed seat/open pressures for the 981s are 105/274 with a 1.7" installed height, assuming the vortecs are around that stock. Seems like its around whats recommended by Isky. I guess its just a matter of whether the 981's will clear the giant valve guides.

I was just thinking of staking the studs as well. Seems like a safer, easier option.

Sonix

iTrader: (1)

Hmm, that didn't sound right so I double checked my numbers, I found 105/294.

1.7-1.150 = .550" max lift. Since you only need .500" (with safety), you can shim it to 1.65" installed, for a good 125lbs seat force.

You can get the comp cutter (and arbor) for another $80 or so, if you need to cut the guides skinnier. If you need to buy a cutter though i'd probably recommend getting one to cut it out to 1.43" OD. I mean, if you have to buy A cutter for $50, you can get the one that cuts the guide diameter to the right ID, and the OD of the spring pocket to 1.25", or get the one that does the same thing but 1.43" OD for the spring pocket - for the same price, might as well go bigger.

The 1.43" springs are only a tad more, and give some room to grow. Realistically you'd use the 1.43" cutter more in the future on more aggressive builds as well.

Geez, I should be getting a kickback from comp.

dimented24x7

iTrader: (2)

My bad. Hit the wrong key. Yeah, theyre 105/294.

I took some measurements of the stock springs. Not super accurate, but good enough to see what Im dealing with.

~OD: 1.220"
~Coil dia.: .175"
~ID: .870"

The nice thing is that there is around .030" of clearance all the way around between the spring pockets and the stock springs, so that should give me enough clearance for the 981's. Theoretically, they should drop right in.

dimented24x7

iTrader: (2)

Also, I wonder what possible side-effects I'll run into by not running a damper spring?

dimented24x7

iTrader: (2)

Would the beehive springs be a better choice in this case? It seems that I could have issues with harmonics without the damper springs. Since the vortecs use some small *** retainers, I'll likely have to replace those regardless, so Im blind to that if the beehives require alternate retainers/locks.

dimented24x7

iTrader: (2)

There seems to be alot of buzz about the 26915/8's. The OD at the base is 1.290". Its going to squeak in the spring seat, but if it works, it may provide better control over harmonics then the plain springs would. Definatly dont want it turning into an out of control slinky every time the valve opens at high RPMs.

Tobias05

curious about needing new retainers/locks as well...

Sonix

iTrader: (1)

What spring doesn't have a damper? The 981's do IIRC, if that's what you were talking about.
Beehives have a very small ID usually, double check to make sure they'd fit. Yea, .690" or so...
Beehives are made not to need dampers due to their design IIRC.

dimented24x7

iTrader: (2)

With the vortecs, the valve guide is so large that you wouldnt be able to run a damper. The current springs also dont have dampers. There are some videos floating around on the net (I found them at http://www.racingsprings.com/movies.htm), and from what was shown in the videos, the dampers do help rapidly dampen out the rebounding waves along the spring after the valve has opened/closed. They showed some dual springs with dampers, and the waves died out in about 2-3 cycles. Even though the beehives continued to have waves traveling back and fourth across the spring the whole time in the tests, it seemed like the non-uniform cross-section did help spread the resonate frequencies across a range rather then concentrate them all at the fundamental.

The base of the beehive springs appears to be large enough to clear the base of the valve guide. The OD is large, but people say they fit. I measured the spring seat as being slightly larger than 1.29". The beehives might not be the best one out there, but its gotta be better then what I have now.
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You might be OK with yours. It looks like the 350HOs used different springs then the stock vortec heads. Theyre 1.250" rather then the smaller dia. that my stock springs are.

Sonix

iTrader: (1)

Beehives are supposed to be the cats ***, i'd say go for 'em.
Unless you want to buy the cutter and then your options are wide open in the future.
Ok, if people have used the beehives on Vortecs then great. I was just leery about the ID of it being too small for the guide.

dimented24x7

iTrader: (2)

I ordered the LS-1 beehives, retainers, and locks. The retainer is also offset, so it should increase the max lift to .500"+. If they fit as advertised, then its stupid easy to get around the max lift issue with vortecs.

Bones232

hey Dim,

Did you plan on measuring the max valve lift once you get your new springs/retainers in? I'm pretty curious as to the lift gains with this setup. As you said, it could be a stupid simple solution for additional lift....

Sonix

iTrader: (1)

I've been singing the praises of this method to increase max lift on heads for a while. No machining involved, simple use offset locks and shim the springs up.

IHe won't gain lift though, since he's not changing his cam... I'm sure that's not what you meant, but it sounded that way by your wording.

Bones232

I was refering to the guide to retainer clearance (max allowable lift).

When shopping for my current cam, I measured each valve for max allowable lift. Then i took the valve with the smallest amount of travel, subtracted a safety factor and that was the cam size I aimed for.

To accomplish this task i installed the valve, valve guide seal, retainer and keepers (everything but the spring) on a given valve. Next I setup a dial indicator to measure the valve movement. With 0 being completely closed, I opened the valve until it bottomed out on the valve guide. That measurement would be the maximum allowable lift (without any saftey factor).

I'm considering a new cam and looking for options related to improving the max lift of these Vortecs.

I appologize if I was (or still am) vague or confusing...

dimented24x7

iTrader: (2)

Well... As advertised, the springs really do increase the max lift to .500"

But, not surprisingly, the pressed in studs are hard as hell and damn near imposisble to drill. I tried drilling them tonight. Not gonna happen. Basically, the drill bit took about 5 seconds to get through the cast iron and then it hit the hardened case on the stud and just sat there for what seemed like forever, and finally I saw shiny metal shavings instead of the grey dust and I thought that it would work after all. Heh, yeah right... The bit hit the other side of the case and it did the same thing again, and by now the bit was starting to enlarge the hole in the stud boss. The bit didnt dull. Good quality bit and it was still razor sharp. These studs are just too damn hard.

Im not even going to bother with the other 15. Its easier to just pull the heads and dump them at a machine shop to get machined for screw in studs.

dimented24x7

iTrader: (2)

Since Im pulling the heads, Im also going to enlarge the pushrod holes so I can run 1.6 ratio magnums for a lift of .465 at the intake and .475 at the exhaust. I bought the 915's so I could shim them, but Im not sure if I want to go to the full 300 lbs of open pressure due to the larger forces that the lifters/cam will be under with the higher ratio rockers. Does around 115 lbs of seat pressure and 260 lbs of open pressure sound reasonable for that cam and 1.6 ratio rockers?

dimented24x7

iTrader: (2)

I lied about the max recommended lift with these springs and the stock valves. Its only .470 For whatever reason, GM made the exhaust retainer sit .030" LOWER then the intake retainer. I thought my eyes where just playing tricks on me when I was looking at the exposed portion of the vavle stem above the retainer, but they weren't. I measured with a head off the motor and the intake has a total lift of .550" while the exhaust only has .520". With teh 1.6's, Ill just sqeak by. Better then before, though. I had only .020" of safety margin with the cam and stock heads on the exhaust side. On the bright side, I probably wont have to shim teh springs, theyre already shimmed by proxy due to the location of teh groove on the valve stem. Figures.

dimented24x7

iTrader: (2)

I took a look at teh stock configuration of the heads with a dial gauge. Im surprised I didnt have any issues with the exhaust side. The max lift in this particular set of heads is .415" due to the exhasut valve having a .280" high valve tip. I was running around .445" inches of lift. Also, the installed height looks a little suspect. Ill have to wait untill I get my spring gauge, but it looks more like its around 1.720" with the LS1 retainers. Would like it to be higher so I have some wiggle room to set things up the way I want them. Ill probably also ahve to get standard replacement valves with the regular .250" tall tip so I can get the full .500" lift capacity out of the heads.

As far as the LS1 springs being an easy fix, that they are not. Not a cheaper way to get more lift, or easier way to get more lift, just another way to get more lift.