what springs?

Grumpy · Jul 5, 2015

I'm building up a ZZ4 block....Rotating assembly is installed and hove purchased the ZZ4 cam....Will be adding AFR 180cc heads...The heads come with these springs: http://www.jegs.com/i/AFR-Airflow-Research/033/8017/10002/-1 Which seem rather stiff to me, considering the stock spring for the ZZ4/LT4 is this: http://www.jegs.com/i/GM+Performanc...PRjh249p9QEvrRS_SWUpCS45QE7aW_TDBqBoCtILw_wcB

its generally a very good idea to keep all the cam, lifter,valve train and cylinder head components in matched sets, keep components in labeled matched sets, if you intend to reuse used parts in a rebuild. as each wears in, or laps in to its matched components a bit differently thus random assembly increases the chances of future parts
failures
https://www.summitracing.com/search?SortBy=BestKeywordMatch&SortOrder=Ascending&keyword=POW735002

I believe the ZZ4/LT4 hot cam springs are a little weak, however, the difference them and the AFR's seems too much to me....Looking for suggestions from those who have "been there and done that" before.

0607phr_32_z+camshaft_basics+beehive_valve_springs.jpg

0607phr_31_z+camshaft_basics+valve_springs.jpg

0607phr_36_z+camshaft_basics+spring_surge.jpg

the reduced diameter of beehive valve springs usually eliminates the rocker too retainer clearance issue

BEEHIVE SPRINGS GIVE A GOOD DEAL MORE ROCKER TO RETAINER CLEARANCE
http://www.kmotion.biz/instht.htm

the first springs are correct for most hydraulic roller cams
http://www.jegs.com/i/AFR-Airflow-Research/033/8017/10002/-1

http://garage.grumpysperformance.co...e-springs-and-setting-up-the-valve-train.181/

http://garage.grumpysperformance.com/index.php?threads/valve-train-clearances-and-problems.528/

http://garage.grumpysperformance.com/index.php?threads/valve-springs.9613/

http://garage.grumpysperformance.co...lve-springs-loads-and-installed-height.10709/
OBVIOUSLY YOULL WANT THE CORRECT VALVE SPRINGS

http://www.competitionproducts.com/1500-1585-OD-Valve-Springs/products/2631/1/0

https://www.summitracing.com/search/part-type/valve-springs

https://www.iskycams.com/cart/valve-springs-c-99.html

http://www.cranecams.com/userfiles/file/334-343.pdf

https://www.racingsprings.com/Valve-Spring/Store/13

http://www.lunatipower.com/Category.aspx?id=23

http://www.pspring.com/products/engine-valve-springs/

http://www.competitionproducts.com/Valve-Springs/departments/49/

http://psisprings.com/products/

http://www.compcams.com/Products/CC-'Valve Springs By Usage'-0.aspx

http://www.racingsprings.com/Beehive-Valve-Springs

https://www.supertechperformance.com/valve-springs-p109

http://www.cvproducts.com/index.php/psi-springs/

The following recommendations are from Erson Cams. If you have questions, you can reach their tech department at 800-641-7920.

Hydraulic Flat Tappet Camshaft: 110 lbs Seat pressure/250-280 lbs open pressure

Solid Flat Tappet Camshaft: 130 lbs Seat Pressure/300-325 lbs open pressure

Hydraulic Roller Camshaft: 130-140 lbs Seat Pressure/300- 355 lbs open pressure

Solid Roller Camshaft: (Minimum Safe Pressures DEPEND ON SEVERAL FACTORS)

Up to .600Ë valve lift: 200-235 lbs Seat Pressure/600 lbs open pressure

Over .600Ë valve lift: 250-280 lbs Seat pressure /100 lbs pressure for every .100Ë of valve lift

CAST CAM CORES ARE NOT DESIGNED TO HANDLE OVER ABOUT 130lbs SEAT and 400lbs OPEN SPRING LOADS YOU NEED A BILLET CAM CORE FOR DURABILITY IF THOSE LIMITS ARE EXCEEDED
Id also point out that youll want to lubricate any valve you install in a valve guide and verify the valve train clearances very carefully, and use the correct valve springs and add the correct valve seals installed
yeah! as I stated the valve spring diameter and heights varies with engine, type.
the cam used and application,yes BBC valve springs tend to be larger as the valves weigh more, but generally there's not a huge amount of compression during the install from the in the box vs the installed height, and obviously the cam generally comes with the installed height, valve spring part numbers and intended load rates that should be used, and yes you still need to use shims, valve spring cups and watch out that at max lift you still maintain the required clearances

Too much clearance will result in the spring "dancing" around in the head, which "beats up" the spring mounting surface and the spring itself. If this is the case, a spring cup may be used. Additional machining of the spring pocket may be required to accept the spring cup.
Not enough clearance will bind the spring in the pocket, overstressing the bottom coil by limiting its movement and not allowing the spring to "grow". This will cause the bottom coil to wear against the head and/or prematurely fail. Machine the valve pocket using a Spring Seat Cutter if not enough clearance exists.

Valve Spring Retainer Fit
The valve spring retainer should fit the valve spring being used. A slightly snug fit is acceptable, however a fit that is too tight can overstress the top coil, and cause it to fail. A fit that is too loose can lead to spring "dancing."

Valve Spring Installed Height
The installed height of the valve spring is the distance between the valve pocket (or cup, or shims) and the outer edge of the spring retainer (which is the height of the valve spring) when the valve is closed. To check installed height, follow the following procedure:

Install the valve in the guide.
Install the retainer and valve locks.
Install all spring cups and/or valve spring shims (basically, everything except the valve spring).
Hold the valve closed by pulling the retainer up tightly against the valve locks.
Measure the distance between the outside edge of the valve spring retainer and the spring seat. A snap gage or a height micrometer should be used.
Check the distance against what is recommended on the camshaft specification card. An installed height of +/- 0.020" is acceptable.
If the installed height is not within 0.020", either machining of the valve pocket, or removal/installation of valve spring shims is necessary.
Repeat this procedure for the rest of the valves.

Valve Spring Retainer to Valve Seal Clearance
The distance between the innermost step on the valve spring retainer and the valve guide must be 0.090" larger than the maximum valve lift of the camshaft. Measure the distance between the top of the valve seal to the bottom of the valve spring retainer. After adding 0.090" to your measurement, it should still be larger than the maximum valve lift of the camshaft. If not, machining of the valve guide in necessary for adequate clearance.

Valve Spring Coil Clearance
Coil clearance is the distance between the valve spring coils when the valve is it maximum lift (fully open). A minimum of 0.060" must exist between the coils at maximum lift. Coil bind is when the valve spring is compressed fully-to the point that all of the coils are "stacked up" on top of each other. For high RPM applications, .100" is recommended . Coil bind is a catastrophic condition that will result in valve train failure. Disassemble each spring (if multiple springs are employed at each valve). Check all the springs (both inner, and outer springs) If there is not 0.060" - 0.100" minimum of clearance between the coils, the solutions are: the valve retainer, the valve locks, the valve, or the spring must be changed; the spring pocket must be machined. Keep in mind that these modifications will change the valve spring installed height

Valve Spring Retainer to Rocker Arm Clearance
When installing the rocker arms, check to see that the inside of the rocker arms clear the spring retainers. Many rocker arms have a "relief" to accommodate large valve spring retainers.

Valve Spring Run-In
Each set of Lunati valve springs are hand-selected to keep load variations below +/- 10% of the next. However, it is important to "run in" your new valve springs at low RPM using the following procedure:

Start the engine and run the engine between 1500 and 2000 RPM until the engine reaches operating temperature.
Shut off the engine and allow the springs to cool.
After initial run-in, most springs will lose a slight amount of pressure. Re-check and shim up the valve springs if necessary. After the springs are "run in", spring pressure should remain constant until the point of replacement.

Grumpy · Jul 8, 2015

bowtie44s asked..

Lunati recommended I go with a 142 seat pressure, 402 open pressure for a hydraulic roller. Do they not know what they're talking about?

yes they do, a 7% increase in seat load won,t be an issue on a hydraulic roller cam valve train in most applications especially if its a hardened or billet cam core, manufacturers don,t want cam/valve train failures its bad for business, so following the recommendations and use of matched components tends to increase durability, (BTW mix & match of various manufacturers components usually voids your warranted as every tech department will invariably blame all failures on the other manufactures parts causing the problem) thus use of a complete package of matched components from the same source as the cam is recommended if your trying to get parts replaced that might fail.

Another question about valve spring specs: Let's just pick some numbers. Say the installed height is 2". If the coil bind height is 1.200, does that mean you won't run into coil bind until you get a cam with .800 lift ?

NO! I can see what your thinking but youll need clearance of .060-to ideally .090 from coil bind, so those springs would more than likely max out at about a .720 lift

Is coil bind height and open height the same thing? The springs I'm wanting to go with have an installed height of 1.940 and open height of 1.250. With .600 exhaust lift, does that give me .090 before coil bind?

installed height is open height, the springs set up to provide a minimal resistance before it can be compressed further, the cam card below may help

notice the listed info

A BIT OF QUICK RESEARCH

Crane Cams#271-99846-16
Single Valve Springs
Outside Diameter: 1.255"
Inside Diameter: .870
Seat Pressure: 125 LBS @ 1.800"
Open Pressure: 383 LBS @ 1.200
Coil Bind: 1.100"
Rate (LBS/IN.): 428
Max Lift: .640
Set of 16

http://www.jegs.com/i/Crane-Cams/271/99846-16/10002/-1

http://www.superchevy.com/how-to/148-0208-vortec-heads-valve-lift/
notice the coil bind height PLUS, approximately the .090 is the listed max lift, and the max lift on the cam or open height is a bit less.
engines require clearances to work correctly and with valve springs having a bit of extra clearance helps durability, this is generally one reason WHY cams are sold with a strongly suggested set of load rates and clearances so they can operate under know and expected stress levels they were designed for

Is coil bind height and open height the same thing? The springs I'm wanting to go with have an installed height of 1.940 and open height of 1.250. With .600 exhaust lift, does that give me .090 before coil bind?

Click to expand...

Grumpy · Jul 10, 2015

If your confused by the terms, lets try this, using this cam and the spring it lists

once installed the valve spring max length is the installed height,

max lift is installed height minus .060 minus coil bind

if you used these valve springs
Crane Cams#271-99846-16
Single Valve Springs
Outside Diameter: 1.255"
Inside Diameter: .870
Seat Pressure: 125 LBS @ 1.800"
Open Pressure: 383 LBS @ 1.200
Coil Bind: 1.100"
Rate (LBS/IN.): 428
Max Lift: .640
Set of 16
coil bind is 1.100 so minus .060 from the installed height of 1.800, you get 1.160 lift,subtracted from 1.800 (.640 clearance) but the valve only forces the spring to compress to max valve lift which will be less than the .640 max lift, while the installed height of 1.800 minus the max permissible lift with that spring 1.800-1.160= .640 in this case the cam lobe lift on the lifter multiplied by the rocker ratio provides a .536 max spring compression, since you have a max usable lift clearance of .640 available with that spring at that installed height,in this case, the .536 lift the cam lobe provides,compresses the valve spring about .104 less than the max permissible lift so clearance will be fine and the valve lift will never reach the full theoretical valve spring compression or load rate listed, it will with the stated load rate of 428 lbs per inch of compression see a lower rate than the listed 383 lbs as .536 lift x 428 lbs per inch of compression= roughly 230 lbs

BTW Im sure the question would come up about swapping to a 1.6:1 ratio rocker, how will that effect the result above?
cams are listed with the stock in this case (SBC) 1.5:1 rocker ratio, in the case above that provides a .536 lift on the exhaust lobe which is a bit more than the listed .518 on the intake,valve, if we were to swap from the stock 1.5:1 ratio to a 1.6:1 ratio you simply divide that listed .536 by 1.5 then multiply by 1.6 and you'll find you'll see a change to a .571 lift, still under the .640 max lift

the valve spring compressor design you use and the use of a large strong magnet can significantly reduce the tendency of those little S.O.B,s from poping off to parts unknown, having the correct tools helps a great deal

http://www.kjmagnetics.com/proddetail.asp?prod=DCA
or
http://www.magnet4sale.com/samarium-cobalt-discs/
$12 or so spent on a decent magnet placed next to the valve keepers during the removal process tends to significantly reduce the chances of lost valve keepers

valve spring compressors
this cheap type is well known for loosing valve keepers unless a strong magnets used

http://store.summitracing.com/partdetail.asp?part=MAN-41830&N=-114082+115&autoview=sku

http://www.jegs.com/i/Moroso/710/62371/10002/-1

Strictly Attitude · Jul 10, 2015

Good info was a nice refresher for me been specing rocker arms and lift specs, proper geometry allong with the effects on the came lca. In order to see if I can optimize my current cam into the new bottom end.

busterrm · Jul 10, 2015

What is the lift of the cam at the valve?

grumpyvette · Jul 10, 2015

(What is the lift of the cam at the valve?)

if your referring to the example listed ,
its .518 intake and .536 on the exhaust with standard 1.5:1 rocker ratio used

what springs?

Grumpy

The Grumpy Grease Monkey mechanical engineer.

Grumpy

The Grumpy Grease Monkey mechanical engineer.

Grumpy

The Grumpy Grease Monkey mechanical engineer.

Strictly Attitude

solid fixture here in the forum

busterrm

solid fixture here in the forum

grumpyvette

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