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What valve springs?

This is a discussion on What valve springs? within the Internal Engine forums, part of the LSx Technical Help Section category; Originally Posted by mark21742 the spring pressure works both ways, up and down, so the power you lose during spring ...

  1. #21
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    Quote Originally Posted by mark21742 View Post
    the spring pressure works both ways, up and down, so the power you lose during spring compression, is gained back on the expansion of the spring
    Not really 100% efficiency in any part of our cars, there is always going to be losses throughout our engines/drivetrain etc. Even if the spring travelled straight up and down on it's own, instead of up/down based on the curvature of the cam, there would still be losses. This is part of the reason why so many people have looked into designing engines w/o cams.

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    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by nhraformula View Post
    you know, sometimes thats not always true.
    years back when i was getting cammed, i called futral motorsports to see what they would recommend.
    at the time i had 1.85 rockers and i had told them so.
    long story short, if i would of listened to them, i would of blew my motor in short order because the lift of the cam would of been way to much.
    Sounds to me it wasn't a spring issue. You are simply trying to cram too much camshaft into the engine and possibly causing piston to valve clearance issues. Futral Motorsports is not a cam manufacture anyway. As I stated, it would be best to talk to your camshaft manufacture for spring recommendations.

    As far as springs are concerned, it's not very wise to go overkill thinking it's better. That can actually be catostrophic and cause more problems later down the road. Not only would stiffer springs cost HP but there are many other more serious affects. One of which happened to me.

    AFR set up my heads with solid roller springs, (320 lbs. seat pressure) knowing they also custom ground the camshaft through comp,,,(a hydraulic roller) that only required 240 lbs. seat pressure. A BIG mistake.
    The engine ran fine on the dyno, put up good numbers, and ran great at the track and the street. After about 5,000 miles it ate several lobes off the camshaft. Yes I said that right,,,,on a roller camshaft too.
    Back then Comp ground their hydraulic roller cams out of cast iron just like their flat tappet camshafts. The hydraulic rollers just don't require the spring pressure. Solid rollers on the other hand require more seat pressure therefore those cams are made of billet steel.
    Now all their roller cams are ground of billet. But this was a costly mistake by AFR with overkill springs that set me back a cam, another set of lifters for starters, and about $1,500 additional dollars when it was all said and done. Could you imagine what this would have done on a flat tappet,,,it's even more critical.

    DO NOT run more spring pressures than is required of the cam manufacture. There are so many new designs out now that I have mentioned with soft closing rates that simply don't require the big springs that people used to run. You will only get into trouble with this type of thinking.
    Most mild hydraulic rollers only require around 130 lbs. of seat pressure and about 300 lbs. over the nose give or take. Setting the installed height properly per cam manufacture specs will dictate spring seat pressure, full lift obtained before coil bind etc... It's very important to not only have the correct springs for the application, but also to set them up properly in the cylinder heads.
    Last edited by Firebirdjones; 01-02-2009 at 07:41 AM.

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    Well, I guess case closed, not really anything more you can say after that...

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    Quote Originally Posted by Firebirdjones View Post
    Sounds to me it wasn't a spring issue. You are simply trying to cram too much camshaft into the engine and possibly causing piston to valve clearance issues. Futral Motorsports is not a cam manufacture anyway.
    Actually i had asked them what they would recommend for me, they told me the FM 13 which would of been a no no.
    Now if that cam would of had a lower lift, it would of been o.k
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    member since may 2000 nhraformula's Avatar
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    Quote Originally Posted by hot93rod View Post
    You raise a good point, you always need to keep in mind the current setup you have in place. 1.85 rockers sounds mighty big even for a stock cam... I would think that adding any more to the lift of the cam, and your piston would send them through the head, lol.
    Yes, it would of been bye-bye motor

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    cutting and welding mark21742's Avatar
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    Quote Originally Posted by hot93rod View Post
    Not really 100% efficiency in any part of our cars, there is always going to be losses throughout our engines/drivetrain etc. Even if the spring travelled straight up and down on it's own, instead of up/down based on the curvature of the cam, there would still be losses. This is part of the reason why so many people have looked into designing engines w/o cams.
    oh true, guess i miss spoke, just saying a bigger spring wont use more power up than a small spring.....your right, they all rob some power though.

    id love to see an (electronic solinoid) setup that would work inplace of a cam

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    ok i got the cam in yesturday and there was no cam card with it.

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    Quote Originally Posted by stephen02ws6 View Post
    ok i got the cam in yesturday and there was no cam card with it.
    im in SC right now and am hoping when i get back to PA monday my cam will be sitting there waiting on me

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    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by stephen02ws6 View Post
    ok i got the cam in yesturday and there was no cam card with it.
    No cam card with a brand new camshaft????


    Who in the world sends out a new camshaft without a camcard. You can't even install it in the motor properly with a degree wheel without the critical open/close specs needed that are on the cam card. No way to know if it's ground correctly on the lobe centers specified without a camcard to use.

    Where in the world did that come from???? I think I would seek services elsewhere.

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    ya there should be a card in the box. i just got my cam and it has a card with it.

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    Senior Member mrr23's Avatar
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    AFR9018 are the best out there. well there is one better, but you'll have to pay about $900.00 for them.

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    i just double checked and there is no cam card in the box and the stickers are off of the outside. i got the cam from lmperformance but they got it from LG. i am going to email lmp to see if they can get me the card for it. what springs should i get? that is the only thing that i am waiting on.

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    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by stephen02ws6 View Post
    i just double checked and there is no cam card in the box and the stickers are off of the outside. i got the cam from lmperformance but they got it from LG. i am going to email lmp to see if they can get me the card for it. what springs should i get? that is the only thing that i am waiting on.
    On the springs it's hard to say without knowing what camshaft profile you have, not even knowing who ground the camshaft is even scarier. Without the cam card I wouldn't even attemp installing the cam in the engine but thats just me. I degree my stuff in, and it helps to know the camshaft is ground properly and sitting in the engine at an advance that you are shooting for. I've ran into issues all the time where the camshaft doesn't fall into the specified advance on the card and you have to move the cam around with offset bushings or fancy timing chains.

    You could take the advice of others and stick any spring in there you want without knowing what spring specs are proper for the given camshaft.

    Will it work?? Ya,,,probably for a while. And it may not give you any problems at all. But thats just not the way I build an engine. But if you are happy with just sticking the cam in there and throwing a set of springs on it,,,,,,,,

    But you are on the right track, that cam card is critical and I would continue to dig for it, whether the seller or manufacture of the cam should provide that. I'm shocked it didn't come with one.

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    they said the card is not available. on the website they recomend the comps so i will probly just order that kit. it isnt lmperformance but LG that isnt giving the card.

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    Quote Originally Posted by stephen02ws6 View Post
    they said the card is not available. on the website they recomend the comps so i will probly just order that kit. it isnt lmperformance but LG that isnt giving the card.
    buy or borrow a degree wheel and mic to check cam centerline and advance.....i got a copy grind with a hand written cam card and no centerline or advance info on it....installing this weekend

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    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by stephen02ws6 View Post
    they said the card is not available. on the website they recomend the comps so i will probly just order that kit. it isnt lmperformance but LG that isnt giving the card.
    Thats kinda scary. Make note to self.

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    Quote Originally Posted by mark21742 View Post
    buy or borrow a degree wheel and mic to check cam centerline and advance.....i got a copy grind with a hand written cam card and no centerline or advance info on it....installing this weekend
    You'll find the centerline with the degree wheel,,,but the real question is.....

    Is that the centerline the cam was ground on?? Is that the way they intended the camshaft to be installed?? Do you want to vary from those specs to gain anything with your particular combination??

    Your centerline will change also depending on how sloppy the timing chain is. Obviously you can compensate for that with offset bushings, but where is it supposed to be according to the camshaft manufacture??? No baseline to start from. Know what I mean???

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    cutting and welding mark21742's Avatar
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    Quote Originally Posted by Firebirdjones View Post
    You'll find the centerline with the degree wheel,,,but the real question is.....

    Is that the centerline the cam was ground on?? Is that the way they intended the camshaft to be installed?? Do you want to vary from those specs to gain anything with your particular combination??

    Your centerline will change also depending on how sloppy the timing chain is. Obviously you can compensate for that with offset bushings, but where is it supposed to be according to the camshaft manufacture??? No baseline to start from. Know what I mean???
    true, i didnt think about that......why cant things just be easy

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    Moderator Firebirdjones's Avatar
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    Quote Originally Posted by mark21742 View Post
    true, i didnt think about that......why cant things just be easy
    LOL,,,ya. You could just stick it in there like most people and run with it. If it doesn't bother you thats all that matters.

    I'm always looking for that little extra in the car, and I'm picky anyway. As an example,,,
    I've found that most aftermarket timing chains will stretch over time about 2 degrees,,,which retards the camshaft. So if intake valve to piston clearance has wiggle room,,I'll automatically set the camshaft up 2 degrees advance to compensate for camshaft stretch later down the road.

    I also move the camshafts around looking for that little extra depending on the combination. Advancing the cam gives you a little more grunt down low,,,but it also moves the intake valve closer to the piston,,,and it also increase cylinder pressure. So if compression ratio is borderline pump gas friendly advancing the cam may not be the best idea. Also if intake valve to piston clearance is marginal then advancing the cam may also be a bad idea. Retarding the camshaft does the exact opposite of all this.

    The weight of the car, gearing, transmission, intake manifold etc...all would play a role in what would be best if you really want to start splitting hairs. Spent alot of time on a DTS dyno playing with this stuff.

    Does this make ya feel any better???

    Just thought I'd throw some more info in the mix and make it more interesting. Doesn't sound like you have much more choice than to just stick it in there and see where it's at and run with it.

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    member since may 2000 nhraformula's Avatar
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    Quote Originally Posted by Firebirdjones View Post
    Thats kinda scary. Make note to self.
    LG Motorsports always have keep their specs on certain cams secret.
    the best bet with them is to call them and ask further advice on springs and such.

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