cam questions

jersey_87coupe
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cam questions

Postby jersey_87coupe » Wed May 07, 2014 5:48 pm

can you run 272 duration and 8.1mm lift on stock buckets/valves and springs
this is for a turbo build
Last edited by jersey_87coupe on Thu May 08, 2014 4:25 pm, edited 1 time in total.

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jondee86
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Re: cam questions

Postby jondee86 » Wed May 07, 2014 6:27 pm

Yes. it will run without any mods, although you might like to consider
upgrading your valve springs as a bit of insurance if you are putting
serious money and effort into the engine. Whether that is a good choice
of cam for your build is up to you ;)

Cheers... jondee86
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meifert
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Re: cam questions

Postby meifert » Wed May 07, 2014 7:34 pm

You should always change the springs with a new cam. metal fatigues over time and the difference in lift could cause failure. You can use stock new springs and you will be good.
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Re: cam questions

Postby yoshimitsuspeed » Wed May 07, 2014 10:00 pm

I'm curious as to what you are trying to do. General oversimplified boosted cam theory is high lift short duration. Why would you choose to go low lift long duration?
What is your build? What are your power goals? Do you already have the cams and that's why you are trying to make them work or are you going out of your way to run them?

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jersey_87coupe
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Re: cam questions

Postby jersey_87coupe » Thu May 08, 2014 4:34 pm

jondee86 wrote:Yes. it will run without any mods, although you might like to consider
upgrading your valve springs as a bit of insurance if you are putting
serious money and effort into the engine. Whether that is a good choice
of cam for your build is up to you ;)

Cheers... jondee86


yea im looking into cams i bit more i know its not the best choice by far. i was just questioning how much lift can stock vlaves/springs handle. :D

jersey_87coupe
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Re: cam questions

Postby jersey_87coupe » Thu May 08, 2014 4:39 pm

yoshimitsuspeed wrote:I'm curious as to what you are trying to do. General oversimplified boosted cam theory is high lift short duration. Why would you choose to go low lift long duration?
What is your build? What are your power goals? Do you already have the cams and that's why you are trying to make them work or are you going out of your way to run them?


I have a build log we've talked in it haha
viewtopic.php?f=7&t=10960

i know a 272 duration and 0.380 to .400 would probably be a better choice cam i was just seeing what the stock valve train could handle. i have looked into the kelford turbo cam but i would like a bit linger duration but still staying in the lift range i mention.

and no i havent bought any cams i wanna make sure of what im gonna get before i do ;)

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Re: cam questions

Postby yoshimitsuspeed » Thu May 08, 2014 10:01 pm

Oh yeah that's right. It's so hard to keep track of everyone.

I have checked in on that thread a couple times but I missed the part about you talking about cams.
Why 270s if you are looking for around 300 hp?

This dyno is on web 101s which are 250 advertised and 229 at .050.

Image

Even with those cams the power doesn't even start to taper down at all by redline. He could have unlocked a lot of power by increasing his redline.
Which brings me to my next point. If you run 270s your power curve is going to move up in the power band beyond the stock redline so you would want to upgrade springs anyway.

Personally I would run more lift with that duration if you do decide to go that way.
I really think you would get a bigger better more usable power band with less duration and more lift.

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oldeskewltoy
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Re: cam questions

Postby oldeskewltoy » Fri May 09, 2014 12:27 pm

jersey_87coupe wrote: i was just questioning how much lift can stock vlaves/springs handle. :D


stock spring can tolerate valve lifts of about 8mm, OR cam lifts of about 8.18mm
OST Cyl head porting, - viewtopic.php?f=22&t=300

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Re: cam questions

Postby The Robot Cow » Fri May 09, 2014 12:55 pm

If i were you just get new valve springs, Hks and Toda units are still available and worth the peace of mind of not worrying about your valve springs with your new cams.
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