NewbVetteGuy

Guys, I just noticed that the product page for these heads from Jegs says that they're supposed to come with a spring locator, but all the springs are sitting in the valve pocket, directly on the aluminum head surface- this means they forgot my locators, doesn't it?


Adam

gkull

Are your springs as big as the head spring pocket? Spring cups are .062 thick. So they would make the installed height shorter. Sometimes the shim type used is there to protect the aluminum head.

REELAV8R

It says ID locators. So there should be something like this inside the inner spring.
https://goo.gl/images/bqCyAu

gkull

I have these on my big dart heads.

http://www.claysmithcams.com/valve-spring-cups/

NewbVetteGuy

So I heard back from Mike Jones and he recommended this beehive spring:
http://www.racingsprings.com/Beehive...1219X/Item/784
145 lbs closed; 358 lbs open ---a special treated version of the 1219 spring that has a little bit more pressure ($15.24 each- OUCH!)

Or this traditional double-spring:
http://www.racingsprings.com/RPM-Ser...1207X/Item/763
155 lbs closed; 436 lbs open ($20 each- more ouch!)



When I get the time I'll post some follow-up questions here to see if I can find the appropriate 10 degree retainers and spring seats and make sure that all the specs make sense.


I might try to find something really similar from Comp to compare prices, but I have more confidence in the quality of the PAC springs. I'd love the retainers to be lightweight tool steel, but this is getting expensive fast.


Adam

HeadsU.P.

Using the palm of your open hand, place it on your forehead and begin a light but rapid tapping to the nogin. Unless you are racing every weekend you sure don't need $320 set of springs, I.M.H.O. Thats just crazy.

PainfullySlow

I have yet to see where comp springs failed. I am sure that you will be just fine with an equivalent unless you are planning for 600+ HP.

NewbVetteGuy

I just tried this a good 20 - 30 times, but it didn't make the price go down...


$15.24 x 16 = $244, not $320 by-the-way.


I've got a heavy hydraulic roller valve train and a very race-like 0.600" lift ; my cam is going to require heavy-duty springs.


The standard 1219 PAC beehive spring is $12.15 x 16 = $194.40, but 135# closed, 348# open. It's a lighter weight beehive spring, and with a lighter retainer so it might be ok, especially if I set my rev limiter at 6,100 instead of the 6,300 I want. -But is the extra peace-of-mind and engine destruction safety worth the $50?!? (Probably.)


Adam

NewbVetteGuy

"Comp Springs" doesn't actually mean anything, though; they constantly change suppliers and you never know what you're going to get. Do some searches for "Comp 918 spring failures" -- Comp had a TON of failures after they switched from PAC as the supplier of their "918" springs to someone else (they were just rebranded Pac 1218s). -There's a guy on LSTech who had 8 out of 16 springs fail pretty rapidly and Comp admitted fault.


Adam

NewbVetteGuy

On this: I contacted Jegs; they said that they should've had the ID locators; they're going to ship them to me.



Adam

Big2Bird

Bad threads and assembled incomplete? I would be sending that POS back to Jegs, not buying more crap.
Upgrade instead.
Edelbrock heads are still made in the USA. Don't know about the others.



I should change my name to TurtleGene. LOL

Big2Bird

I should add, my logic is this.
This is JUST the stuff you have spotted and found.
What's next? A bolt hole off?
Core shift?
Long Block is where you spend the money.
Anything else, dist., carb., manifold, etc.is a breeze to change.

REELAV8R

At full lift on the intake according to the spec sheet you should be .075 from coil bind.
This leaves you .015” left for a shim to adjust the seat and nose pressure higher.
I would check with Jesgs to see what the spring rate is.
Multiply that rate( ie 350#/ inch ) by .015 and see how much pressure may be added.
I would also invest in a valve spring height micrometer. Better check it whether you buy new springs or not.

https://goo.gl/images/eCYA8H

You may be able to use the springs supplied with the head.

NewbVetteGuy

Big2Bird

I understand.

NewbVetteGuy

It costs $1,107.32 to buy the bare heads from profiler; even if the only thing I keep is the valves and retainers, I paid $998 shipping and tax fully assembled with valves, seals, retainers, keepers, rockerstuds. I’m still happy with them for that.

ronarndt

Agree. I spent a couple weeks trying to diagnose rpm die-off at 5K rpm on my 454 with pre-assembled aluminum heads. Finally I checked the installed spring height and it was way off. This decreased the spring pressure and allowed the valves to float at 5400 rpm. Shimming the springs corrected the problem. I also invested in a Moroso spring pressure tester just to verify correct pressure.

NewbVetteGuy

I'm not seeing what you're seeing. Can you help explain to me how you go to those #'s?


When I go to the Jegs site for the heads that I posted (here: http://www.jegs.com/p/JEGS-Performan...93012/10002/-1), it says that the seat pressure is 135# @ 1.800" and 340# when the valve is opened and the spring is compressed down to 1.200".

It also says that the max valve lift is 0.600". 1.800" - 1.200" == 0.600"; I've been told that springs normally have the max lift rated with 0.050" - 0.060" of "extra" room before spring bind occurs.

Oh... Now maybe I understand, it says that spring bind occurs when the spring is compressed down to 1.125" so if I take 1.200" - 1.125" = 0.075" that tells me how much ACTUAL room I have, right?

Hmm.. But then there is supposed to be a spring locator that's 0.060" thick installed, too, so now I'm really confused. -I guess I just can't use the statistical #s and have to actually measure because "installed height" doesn't mean any sort of absolute height from the heads' spring pocket surface to the height of the keeper groove that's ground into the valve stems?


I guess if all Jeg's #s were ASSUMING that the 0.060" keeper was installed already, then I'd have an additional 0.015" to install a shim and gain a bit more seat and open pressure, right?




All so complicated... Still not feeling confident that I understand it.



Adam

REELAV8R

You got it! Yes that is correct.

If you want to check coil bind height, put a spring in a vise and clamp it down until coil bind (not really cranking on it just till all coils are compressed), now measure the size of the spring. That is true coil bind height.

Careful with the springs you don't want to damage the finish on the spring, maybe use some soft jaws in the vise or cloth or wood so as to not put a crease or big scratch on the spring. Doing so can put an area of stress for future failure in that spot.

Yes.
Get the installed height micrometer. I can guarantee you that the installed height as delivered will not be what is advertised on each valve.
The installed height they advertise may be correct on cylinder #1 for one of the valves, but the rest will probably vary. And they may all vary from the claimed 1.8" install height.
this means that your seat and over the nose pressures will also vary. Just try to get them all close to each other within the confines of coil bind and the available shim thicknesses.

Even on my AFR's the installed height varied from advertised. I shimmed all the valves up at least .015 for a 150 ish seat pressure and a 360 ish over the nose pressure. Your over the nose pressure will vary depending on the spring rate and the lobe lift height.

NewbVetteGuy

I don't understand how to measure the actual height of the springs as installed on the head; there's no way for my calipers to get in there, but I've got a very small metal ruler with a slide on it and it definitely seems like it's in the 1.75" - 1.8" range (The other head has all of the I.D. locators on it).


I don't understand how an installed height micrometer would measure the actual installed height. Do you click the retainer and keepers on over it with the valve installed? (so it's installed in place of the springs?) -If so, then it makes total sense.


Adam