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Discussion Starter · #1 ·
i was wondering if anyone new how much lift you could put on the stock valve springs and still be safe. I want to get some camshafts and cant afford to get the aftermarket valve springs right now(im not very patient when it comes to upgrading my car lol). I guess its prob. better if i just wait and get the aftermarket springs.
 

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Shot me 3 deer!!!
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It is not more than a .410" lift and that is pushing it. I wouldn't put a high staged cam in if the springs have a crap load of miles on them as the springs will lose a bit of "umph" and you will get valve float earlier!
 

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Shot me 3 deer!!!
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whats the gross lift?? I'm assuming you will be fine!!! I ran Crower II's on my car for about 1k miles on a stock head. The lift is a .413" I prolly shouldn't have, but o well. then the car was in an accident and i got a new head anyways. the car had 80k on it. I am 99% sure the FR2's aren't even close to as aggressive. <.400" lift, so I would think you would be fine!! you may want to eventually replace ur valvetrain though. If you start to get valve float at about 6k, then your springs are prolly gone!!
 

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Shot me 3 deer!!!
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u know if you have valve float by ur car not making any more power, for example, if you had it at 5k (highly unlikely) u would say be in first gear and you wouldn't be able to push past 5k in first. what happens is the valves can't open and close quick enough so the air is never flowing right anymore. this is because the valve springs cannot overcome the momentum in between each of the camshaft cycles because they lose contact w/ the camshaft. This prevents going any higher in the rpm band and making power efficiently. It will also ware out the valvetrain components much faster if u are constantly in valve float. if you didn't have a rev limiter, you could go past 7k, but you would only make power to 6500 rpm on stock camshafts. but because the valvetrain is limited, you really don't make very good power after!
 

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Shot me 3 deer!!!
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If they have a gross lift of only .347", then you will be more than fine!!, but you may not make too much power over 6500 rpm.
 

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The Godfather
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The stock valve springs are pretty stout. I ran a very aggressive kent cam (good lift, long duration) to 7200 for more miles than I can even remember. I doubt you will find much off the shelf, run of the mill cams that will find a way to break the valve springs.
 

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Shot me 3 deer!!!
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I know people have had issues w/ the crower II NA cams w/ a .413" lift on an older stock head. I just chose to put the FR vavles in and i get no valve float up to 7600 rpm. of course I have the retainers and oversized valves to go w/ it!! but still. ur valve sprins do ware out, so if you have a high mileage fofo, then you could run into problems. but w/ a .347" lift you will be just fine unless the head has 200k miles.
 

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Shot me 3 deer!!!
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yup and while ur at it, get the wider valves!! then you will have a fully built head capable of alot higher rpm!!
 

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Discussion Starter · #13 ·
yup and while ur at it, get the wider valves!! then you will have a fully built head capable of alot higher rpm!!
How much did you give for someone to do the vavle job? I'm assuming u have to bore the vavle seats to get the bigger vavles right?
 

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Shot me 3 deer!!!
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all my head work wass done by a friend at school, well, a friend of a friend who has his own shop. he charged me 40 bucks!! lol, so i don't think thats going to help you too much!!
 

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Discussion Starter · #16 ·
cool, how much are the vavles themselves (teh oversized ones of course)?

trying to get my zetec to breathe better
 

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C2H5OH
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I really see no stock spec's in here yet so here goes:

Test Pressure Open (intake): 82# @ .988 Green Spring
Test Pressure Closed (intake): 36.6# @ 1.346 Green Spring
Test Pressure Open (exhaust): 95# @ 1.027 Blue Spring
Test Pressure Closed (exhaust): 45.5# @ 1.346 Blue Spring
Free Length: 1.732" (both Green and Blue)
Installed Height: 1.346" (both Green and Blue)

right from the AERA spec sheet for a 95-00 Contour vin 3, not sure yet if the Focus differs or not, I'll get back to you on that.
 

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Discussion Starter · #18 ·
Test Pressure Open (intake): 82# @ .988 Green Spring
there's no way that means they can withstand .988 of lift could they?

im sure this info is really helpful but, i dont understand it LOL

maybe you could expain if you have the time?
 

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Shot me 3 deer!!!
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no, they can't withstand that, plus you would slap the piston!!
 

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C2H5OH
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That is spring height when the valve is open, and spring height when the valve is closed. So on the intake side you have .358" of valve travel and the exhaust is .319". Make sense now?
 
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