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[308] valve spring issues.

ari666

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just noticed yet another snapped spring. this one is down by the base and wouldnt have had much effect on vac, so it may have been broekn for a while, i just dont know.

however, this makes the 3rd broken spring from these springs. they were brand new 'from the box' LT1 springs to suit my crane 286 cam (496 lift 230 duration, 112 seperation)

the problem is when i bought them i had stock rockers, i later put yella terra 1.65 adjustables which brings my lift to around .511. i asked dude-face-sales rep (when the first spring broke) why it wouldve snapped and if 511 was too much lift for it to handle.

his response was "well you probably shouldnt be revving it to valve bounce" which is weird cos' i hadnt finished running in the build and had not once ever reved it past 4k rpm...

so i loosened off all my rollers a touch and drove it for a month or so with no further problems, till' one day my vac guage started going off its face and the engine started missing, limp it home, sure enough, broken valve spring.

i rang dude-face-sales rep again and asked "are you SUUUURE 511 is ok with these springs" and his response was pretty much the same as the first time. the thing is i dont rev my engine that high, i have the limiter set on 5500rpm cos thats where my power peaked on the dyno. so saying its my fault is BS

ive been looking around for springs and come across these: CROW #4843 Crow Performance V8 Holden Valve Springs (4843) (eBay item 160569697288 end time 17-Apr-11 08:38:12 AEST) : Cars, Bikes, Boats

in the listing it states they are good for 550 lift with no machining and stock collets/retainers. does anyone know if 511 is too much for LT1's. could there be another reason for them snapping? my driving is not at fault, so forget about "try not revving it to valve bounce" too tight roller rockers? anti pump lifters the cause?

anyone used those crow springs? is it true about 550 lift, or is it just a tall story? i have heard the only way to get 550 without machining is to replace the collets/retainers with .050 recessed bases.
 

delcowizzid

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how much preload you running the rockers at
 

immortality

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yeah, those springs will do the job. depending on which springs you have now you'll probably have to much lift for them.

did you check to see what the installed height of your current springs are?
 

ari666

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delcowizzid

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if they are antipump lifters they will rattle and should have none to minimal preload its how they dont pump up they have very small preload to not allow any movement to pump up
 

VR38

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They are pretty cheap and nasty looking springs.
 

Boonz

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hey ari, i had the same problem with the crow springs in my ute with the same cam and rockers, ended up being **** material used in the springs in the end according to the crow cams diagnosis.
ended up getting a set of isky springs for $175 with slightly more seat pressure at the same installed height and havent had a problem since
 

ari666

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cant find those springs in stock anywhere, everywhere has to order them in, so i am looking for something else now. wanna get this resolved today.

just checked for coil bind and there is about 2.5mm clearance between each coil, both inner and outer. BUT just measured install height and its 1.75", rather than 1.7" that i asked the head reco'ers to check... still not sure if that would make things snap, but it does mean i can look for slightly taller springs, and not worry about recessed base collets.

does anyone know if the anti-pumps will lift to full without oil in the engine? its been dry for about 2 or 3 weeks now, and am guessing there is about 50 thou of travel from the hydraulic factor.
 
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