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Cal-look/High Performance => Pure racing => Topic started by: Todi on April 20, 2009, 19:59:39 pm



Title: Rpm question
Post by: Todi on April 20, 2009, 19:59:39 pm
Can some one tell me how much Rpm a pair of CB Wedge Port Heads 44x37,5 will do direct out of the box, no make over. I have a Fk87 cam.


Title: Re: Rpm question
Post by: Bewitched666 on April 20, 2009, 20:10:45 pm
Damn thats a ruff one but i dont think heads will have influence on your rpm.
Rpm depends on the rotaing mass like crank,cam etc. But i think your cam can hit in the 8000 rpm


Title: Re: Rpm question
Post by: airstuff on April 20, 2009, 20:17:01 pm
the springs will suffer,and wil get softer,do you have normal springs and valves,or do the heads coem with their LS-1 valve/spring package.

FK-87 creates a lot of lift,for VW lenght springs.


Title: Re: Rpm question
Post by: Todi on April 20, 2009, 20:54:39 pm
the springs will suffer,and wil get softer,do you have normal springs and valves,or do the heads coem with their LS-1 valve/spring package.

FK-87 creates a lot of lift,for VW lenght springs.

The heads I have is 94 bore and what I can see you will only get LS-1 with 90,5/92 bore, or am I wrong..... How about some Chevy springs then? 


Title: Re: Rpm question
Post by: airstuff on April 21, 2009, 11:01:29 am
the springs will suffer,and wil get softer,do you have normal springs and valves,or do the heads coem with their LS-1 valve/spring package.

FK-87 creates a lot of lift,for VW lenght springs.

The heads I have is 94 bore and what I can see you will only get LS-1 with 90,5/92 bore, or am I wrong..... How about some Chevy springs then? 

You must know how much you payed for the,then you know what is included.

Some Chevy springs would do better with this cam,but here are people who can tell you exactly what you need.

Come on guys :)


Title: Re: Rpm question
Post by: BeetleBug on April 21, 2009, 11:17:16 am
Without the LS1 package you`re on the limit and close to coil bind when you have reached the correct pressure. And no, you do not need Chevy springs or K800`s. The FK87 is easy on the valve train and do not need monster spring pressure.


Title: Re: Rpm question
Post by: Ohio Tom (DdK) on April 25, 2009, 05:09:04 am
With the 87 cam, the lobes have very gentle ramps. As long as you keep the valve lift reasonalbe, you can make the springs last a little while.
However, even with worn springs, you should still see 6,800-7,000rpm before valve float.


Title: Re: Rpm question
Post by: JS on April 25, 2009, 08:53:14 am
Those springs wear out kinda fast, I have revved mine to 8000 a couple of times, normally I shift at 7000 at the drags.
After 2000km on the street and a few drags (one short summer) there were only 110lbs left in them...


Title: Re: Rpm question
Post by: Todi on April 25, 2009, 11:11:12 am
So it seem to be a good idee to change the springs I have now in to my chevy ones... Can point out that the engine I have is for dragracing only!   


Title: Re: Rpm question
Post by: Shubee2 (DSK) on April 25, 2009, 14:57:29 pm
I would not use them right out of the Box First off do A 3 Angle valve job on them and check for coil bind  depending on cam used and spring seat pressure  before just bolting a set on..


Title: Re: Rpm question
Post by: Todi on April 25, 2009, 15:57:47 pm
I would not use them right out of the Box First off do A 3 Angle valve job on them and check for coil bind  depending on cam used and spring seat pressure  before just bolting a set on..

Sorry for my bad english, but coil bind ??


Title: Re: Rpm question
Post by: j-f on April 25, 2009, 16:14:20 pm
I would not use them right out of the Box First off do A 3 Angle valve job on them and check for coil bind  depending on cam used and spring seat pressure  before just bolting a set on..

Sorry for my bad english, but coil bind ??

There is a thread where Jim explain how to check coil bind. It's the clearance you have between each spring coil.


Title: Re: Rpm question
Post by: JS on April 25, 2009, 17:25:43 pm
How long can you expect valve springs to last in a high hp application on our engines before loosing a lot of tension? I see the top fuel guys check them after every run?


Title: Re: Rpm question
Post by: BeetleBug on April 25, 2009, 17:47:24 pm
Try this;

Take out one or all your new, unused springs and messure them, then press them all the way to coil bind and messure them again. Do not be suprised if you have lost spring pressure. Crappy springs are a problem.