stock vortec valve springs?

[Blue85]

Are the factory springs in vortec heads ok to use with a hydraulic flat tappet cam, is there enough spring pressure?

[jamis]

The lifer type is not critical, it’s the total lift (at the valve) and RPM that can cause valve float or coil bind.

The L31 vortec max lift rating is .420 it has 75 pounds of seat pressure @ 1.7 installed height. Check your cam spec for what is needed.

[Tom]

Originally Posted by jamis

The L31 vortec max lift rating is .420

Funny, the stock vortec cam has more lift then that
Stock vortec springs are rated to .480" but some heads have shown retainer clearence issues at .470".

[jamis]

Here are the specs copied from GM. Vortec is just a trade name, there where more then one head configuration. The problem is you find a lot of different specs described as "vortec". Some are not GM specs, but aftermarket engines describing themselves as a “vortec” engine because they are using “vortec” heads.

The complete L31 engines part# 12530282 and 12530283 are both Vortec engines found in trucks. The 12530283 is the heavy duty version with 4 bolt main and different head configuration but both use the same cam.

Intake Lift- .414"
Exhaust Lift-.428"
Intake Duration @.050"- 191
Exhaust Duration @ .050-196
Lobe Centerline-111

These specs are for the the L31 which is the truck engine head configuration that is most commonly used for performance. . This is the same casting I’m using but I'm running aftermarket valves, springs, retainers bla.bla bla

Part Number: 12558060
Description: L31 with valves
Material: Cast Iron
Head Bolt Torque: 65 ft./lbs.
Valvespring Seat: 1.300” O.D., 0.850” I.D.
Valve-guide Seals: Viton rubber positive seals, total 0.450” retainer-to-seal clearance Combustion Chamber Volume: 64 cc
Spark Plugs: Straight
Heat Risers: No
Valvesprings: Single wire with damper 1.235” O.D., 0.875” I.D. 75-pound seat pressure @ 1.700” installed height Coil-bind @ 1.150”
Intake Bolt Pattern: Four bolts per side
Rocker Arm Style: Self-Aligning Intake Runner Volume: 170 cc
Valve Diameter: I: 1.94”, E: 1.50”
Casting Numbers: 10239906 and 12558062
Max. Valve Lift: 0.420” which allows 0.030” retainer-to-seal
Rocker Stud: Press-in, 3/8” diameter
Spark-plug Style: 14 mm, ¾ reach, tapered seat
Notes: LT1 Design Port with valves and springs.
Click here for a comparison chart of intake and exhaust flows. Click here for a slightly bigger picture of a Vortec head.

[Billla]

If you're looking at the GMPP new head P/N 12558060 the max lift is .475; the spring is the 10212811 spring, 80#@1.7 installed height.

Agree with Jamis that it's not about the lifter type, and that you should compare the spring specs to those recommended by your cam manufacturer and see how they map.

[Blue85]

the heads are factory 062's, I would probably just switch to the beehives, but i need to throw a cheap motor together to get me through the summer, and I would like to use the 062's instead of the 882's as long as I can find a cam to work with the stock springs. I read somewhere that the 062's stock springs are a little lighter because they were used with a roller cam.

[jamis]

It wouldn’t matter if it was roller or not. Rollers are used to reduce friction and you can have steeper lobe ramps to increase duration without increasing lift when changing the profile. A roller with .460 lift would likely have the same spring rating as a flat or mushroom tappet with .460 lift. Ramp speeds and RPM can also have an effect but not as much as total lift.

Be careful if you’re identifying your heads by casting numbers, Casting numbers do not identify what springs came with the head. Only the assembled head part number can ID the spring. Or you have to remove the spring and measure it and its pressure.

Your retainer to seal clearance and coil clearance will limit your lift as well.

Whats a beehive on an engine, I never heard that term before.....I guess I'm showing my age?

[Blue85]

The beehives i'm talking about are comp cams beehive valve springs used to get more lift out of vortec heads. Heres a link to rage'nrats thread on installing the beehives http://67-72chevytrucks.com/vboard/s...d.php?t=223092.

[jamis]

Originally Posted by Blue85

The beehives i'm talking about are comp cams beehive valve springs used to get more lift out of vortec heads. Heres a link to rage'nrats thread on installing the beehives http://67-72chevytrucks.com/vboard/s...d.php?t=223092.

WOW those beehives spring are great, you don’t have to enlarge the spring pocket. I see now why they are called beehives, because they are a large diameter in the center coils, shaped like a beehive. Thanks for the info I will keep them in mind for my next build

[Blue85]

OK nevermind, just had a closer look at my springs and found out that someone has already enlarged the spring pockets and it has regular size springs on the heads, 1.23 inch diameter or something, can't remember exactly right now. Guess now i gotta try to find out the springs tension. Wish i woulda checked a bit closer before i started askin questions!