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[carlosl]

Hi, i'm building a 2L zetec turbo just wanted some opions on valve springs to use, has anyone used the piper uprated ones.
thanks

[BUTRE]

If you're using the std cams and std con rods (even if they are balanced) there is no point on going different valve springs than std fords.

Std cam does not have an agressive profile that will give you valve bounce of seat or even spring recoil.

Std con rod's are only safe to rev up to 7200rpm, and that rpm is more than enough for std valve springs.

Without any big engine breathing improvement, your engine's peak power won't be over 6500rpm so no point of reving too much over that.

[carlosl]

thanks for the reply, do you know what sort of boost uprated ones can handle, I read that the standard ones can only handle about 8psi before valve bounce happens, I wanted some to handle 15- 20 psi.

[saqmaster]

The standard valve springs cause valve float at around half a bar of boost and 5500rpm. You should get a set of Piper uprated valve springs (they only do one for the Zetec-E, so you shouldn't get stuck!). Cost is around £120.

[BUTRE]

Valve bounce is diferent of valve float.

Valve bounce is when the valve hits so hard on its seat and rebounds off it's own seat. This happens on high lift aplications and the best way to get around this problem is to use stronger springs.

Valve float can mean two things: high boost aplications will make the valve closing more difficult and/or the natural harmonics of the spring beeing achived making the spring vibrate and making a "closing pressure" non-progressive.
This is cured with stiffer double springs.

Triple valve springs with really high lift valve:
http://www.youtube.com/watch?v=i_NpzU4pGjc

I really doubt that std zetec valve springs can give you the float problem at so low boost... unless they are worn.

Going springs too stiff will put all valvetrain under stress when the most of times is not necessary... some ppl just like showing their engines spec list with lots of custom and uprated parts

[BUTRE]

Valve bounce is diferent of valve float.

Valve bounce is when the valve hits so hard on its seat and rebounds off it's own seat. This happens on high lift aplications and the best way to get around this problem is to use stronger springs.

Valve float can mean two things: high boost aplications will make the valve closing more difficult and/or the natural harmonics of the spring beeing achived making the spring vibrate and making a "closing pressure" non-progressive.
This is cured with stiffer double springs.

Triple valve springs with really high lift valve:
http://www.youtube.com/watch?v=i_NpzU4pGjc

I really doubt that std zetec valve springs can give you the float problem at so low boost... unless they are worn.

Going springs too stiff will put all valvetrain under stress when the most of times is not necessary... some ppl just like showing their engines spec list with lots of custom and uprated parts

[saqmaster]

butre- if you've not done the tests yourself, i suggest you leave the advice to those who have

[BUTRE]

butre- if you've not done the tests yourself, i suggest you leave the advice to those who have

You got that right, that's why I only speak in what I've seen be done.

Have you tried new std valve springs? Your used used ones from the engine you bought from scrappy and getting new uprated ones gave you the idea that std ones are crap for low boost?

[saqmaster]

butre- if you've not done the tests yourself, i suggest you leave the advice to those who have

You got that right, that's why I only speak in what I've seen be done.

Have you tried new std valve springs? Your used used ones from the engine you bought from scrappy and getting new uprated ones gave you the idea that std ones are crap for low boost?

No, extensive dyno work has displayed where the standard (new or used) springs top being useful.

[saqmaster]

note: but i do apologise if that sounded a bit harsh

[carlosl]

Thanks do you know what sort of boost they will be able to take was after running around 15-20psi would they be ok.

[saqmaster]

Thanks do you know what sort of boost they will be able to take was after running around 15-20psi would they be ok.

From my experience, no, you'll need uprated ones.

[BUTRE]

butre- if you've not done the tests yourself, i suggest you leave the advice to those who have

You got that right, that's why I only speak in what I've seen be done.

Have you tried new std valve springs? Your used used ones from the engine you bought from scrappy and getting new uprated ones gave you the idea that std ones are crap for low boost?

No, extensive dyno work has displayed where the standard (new or used) springs top being useful.

top or stop?


I don't want to say anybodys work is bad but I really doubt that.
To become more accurate, what valves where used? Can you tell us the valve poundage from the used, std and uprated ones you used on dyno?

[saqmaster]

Sorry, I meant stop.

I'm not really at liberty to disclose the info you ask for as it doesn't belong to me..

[carlosl]

Sorry I meant to put will the uprated piper ones be ok at 15-20psi, I would rather buy them now while the engine is apart.

[BUTRE]

We 3 are posting to fast and keeping updated of all comments are starting to be hard

saqmaster, you're not sounding too harsh... I like to have new ideas about getting around problems. This is the main reason I use foruns.

[saqmaster]

Sorry I meant to put will the uprated piper ones be ok at 15-20psi, I would rather buy them now while the engine is apart.

Do it..