valve springs(gasser)

[malibu795]

some of you know my malibu took a shit thrusday night going home from johnys
finally got the engine pulled and torn apart. i thought i colapse a couple lifters and possible flatened a cam

good news is cam/lifters are still good

what i found was a broken vlv spring on an exhaust vlv im glad i didnt drop the vlv

im running k-motion 700 120# closed 375 open 1.265" spring rated for .500" lift. as for cam im runing a 214/224 with .471"/.496" with 1.6 rockers factored in. the engine has not been reved higher then 4500-4800rpm

any one want to take a gues at why it broke i highly doubt i floated the springs.

im not sure if i should up grade all 16 spring or just replace that one spring or just up-grade the exhaust...

 

[Lonnie]

Personally a .500" spring with a .496 lift cam is cutting it close. Did you verify every spring installed height & also measure the coil bing height to be completely sure you were safe. Generally .060"extra is a good minimum.

Even though you are using a good brand spring, I would possible consider a spring with a little more safety margin.

Were these springs recommended for this cam? If so, probably with 1.5 rockers...

 

[Gasuout]

coil bind is my guess .

man id be revvin that thing 5800 at least

dont let me drive it .

 

[malibu795]

install hieght is 1.700"
bind is 1.050"
i got ~.650" till i bind the springs

for a small HYD flat tapper 100-135lb close is the normal recomended seat pressure. bigger the cam heaveryu the seat pressure

the cam is a summit knock off 1103

cranes recomended srping is 99848-16
Closed 114 LBS @ 1.700 or 1 45/64
Open 303 LBS @ 1.270
rate 432 lb/in

the k-motion 700
120# @ 1.700
375# @ 1.150
rate 464 lb/in .500" lift cap.
if i upgraded i would be puttng kmotion 750s(drop damention are same between 700/750s along with retainers)
130# @ 1.700
395# @ 1.150
rate 482lb/in and a .610 lift cap
(side note i run these in my 500hp 383 that i spin to ~7,000 with no float .
.520/.544")

 

[Gasuout]

then it just broke , replace and run it .

 

[MMLMM]

I hit at least all the exhaust on that side since your there. Prolly should do all on that side though.

Have you checked the adjustment on the other springs see if any others are off by chance?

 

[malibu795]

the spring are all when i put them together in 06 and they are all 1.70X" install height

i think it was what johnny just said "just broke" for no reason.. maybe manufacture flaw :dontknow:

both head are off and going to get a quick valve job tuesday. @ running coast of 100 bucks

i sent k-motion an email with the pic i posted..

leaning on johny reasoning replace said spring and go with it. tho i do wnat to know "why" it broke on me

 

[Stingpuller]

Valve Springs

Malibu I would get a new set of springs. Go with H-11 spring possibly a K-750 seems a lot better, or a crane spring in a H-11. Both would drop in on your heads and istall with no problems. You were very lucky you didn't drop a valve. Jeff

 

[malibu795]

pulled the head and check mesurment...
first off i have know idea WTF i did or was thinking when i put them together

i have a ressesed area of ~.030" the width of 1.265 OD same size as the springs. the vlv spring seats are cut for 1.440 from world products measureing there i get and install height of 1.803" with the ressesed area is 1.833"

dont know if the resessed area was there from the factory or not.

according to spring pressure date from k-motion http://www.kmotion.biz/springpress.htm
with k-700 springs
1.800 install height is 74lbin @ .500" lift 305lbin
1.850 install height is 50lbin @ .500" lift 282lbin
:cussing:

one option is stacking a .015, .030 and .060" = .105" of shims to get me back to 1.73X" not something i want to do...

another option is i got the k-800 siting here for my BBC that i was building.

still no clue why it broke.... floating at 4200rpm is highly possible

know more tomorrow when i call both tech line for k-motion and world products :baby:

 

[Lonnie]

Sounds like you can put 2 .060's under each spring & get close. I would work backwards, first measuring the actual spring height required to get 120# on the seat (find someone with a spring tester). Then see if you still have enough lift before coil bind. It is not uncommon to lose 10-20psi seat pressure after the springs break in.

Also make sure the top shim is hardened so the spring does not cut into it.

 

[malibu795]

deffantily something i am going to do.

make the finall discion tomorrow after i talk with world casting about the vlv spring seat. it is possible th spring at that .030" out of the seat.

 

[Donna_and_John]

Some of the higher performance single springs in a lot of applictions can have failures like this. All it takes is a tiny flaw in the material (like a small piece of crap in the metal mix), and the spring will fatigue and break. Some of these singles are supposed to be replaced every 12k to 15k miles as well.

Personally, I would replace all the springs. Murphy's Law says one, or more, of the others will break soon after you get running again. Easier to just do it now.

I'd also recommedn running a good dual spring instead of a single. If you have an outer spring fail, you don't drop a valve. Cheap insurance for the motor, IMHO.

Had one of our REV duals break in the Vette two years ago. Idle quality sufferred (it would die and throught he misfire trouble code) and it became hard to start some times. Not sure how many more miles we put on it before it got bad enough that I put it in the shop, but the motor sufferred no damage at all. Replaced all the springs with new duals and been running perfect ever since.

 

[malibu795]

they are all getting replace.

just got to find out what i can do with the heads.

the k800 i have are double springs... might just have them cut the seats so i can get the intall heigth of 1.850-1.900 nets ~140lb seats

 

[malibu795]

talked to world products said spring seat are good just stack shims.

talked to k motion... said since they were installed at 1.800 with the .496" lift they were "floating solid" and that it was a fatige break.. also strongerly sugjested i upgrade to the k-750s

should be up and running by wednesday/thursday

 

[Lonnie]

No matter what you do, check your springs for tension before you install.

I recently was shocked to find that a motor I was spinning to 7600rpm had the wrong springs. They were 30psi short on the seat alone. I changed the cam & just needed to shim them for more seat pressure to make them suitable for the new cam. When I put them on the spring tester, I found that they would not come up to tension without a ton of shims & the corresponding open pressure was way low. At first I thought they were fatigued, but I started checking wire dia. etc. & found they were not the correct springs. I'll never put in another set without checking pressure.

 

[malibu795]

yeah i can understand that

max rpm this stock bottom is going to see is 5000-5500

wouldnt surprise me is it pull stronger now :rofl: