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Double valve springs
https://www.ausmini.com/forums/viewtopic.php?f=2&t=5836		 Page 1 of 1
Author:  J_A_M [ Sat Mar 26, 2005 9:23 pm ]
Post subject:  Double valve springs
My 202 head hass double valve springs.

Is the idea of these purely to let your engine rev harder?

My impression is that it makes opening the valve harder, or stiffer. Wouldn't this then transfer back to the cam, and wear your cam lobes quicker?
Author:  benjamin [ Sat Mar 26, 2005 9:24 pm ]
Post subject: 
possibly but you dont get valve bouce
Author:  J_A_M [ Sat Mar 26, 2005 9:54 pm ]
Post subject: 
the cam followers that came out of the motor with the 202 head fitted, were absolutley shagged!! I wonder is this is from the extra resistance in the double springs?
Author:  kazjim [ Sat Mar 26, 2005 10:12 pm ]
Post subject: 
Yes, but in engineering EVERYTHING is a compromise....

is the extra Rev worht the 1-2 Hp that you lose through friction on the cam ?

In my world.. yes.

I ran Triples on my Holden V8 for a while...... 7500 RPM in a 4.2 litre...nice...

J
Author:  J_A_M [ Sat Mar 26, 2005 10:19 pm ]
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mmm...nice...i dont think i have had a holden 8 that reved over 5500 - 6000.....
Author:  drmini in aust [ Sun Mar 27, 2005 6:07 am ]
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Standard single springs are for standard cams. If you try and run them on a performance cam, the followers will not follow the cam lobe profile, both they and the cam will suffer.

Your double springs I saw will be fine with an RE-13 (or similar) cam for up to 7000 rpm (plenty)..

Possibly the followers in the motor are original and have seen several cams (another no-no). If you regrind a cam you should fit NEW followers.
:wink:
Followers available today (MiniSpares/Karcraft ones) are better made than those of yesteryear.
Author:  J_A_M [ Sun Mar 27, 2005 7:31 am ]
Post subject: 
yea, I have Tuesday off work.....going to either Heritage or Karcraft for a buying spree :wink:
Author:  steveandsash [ Mon Mar 28, 2005 5:51 pm ]
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so the single valve springs i have at the moment will be not good for the re13 cam i have just put in?
could that cause really bad running?
see the other post i'm about to put up re bad running.
\
cheers steve
Author:  drmini in aust [ Mon Mar 28, 2005 6:57 pm ]
Post subject: 
steveandsash wrote:
so the single valve springs i have at the moment will be not good for the re13 cam i have just put in?
could that cause really bad running?
see the other post i'm about to put up re bad running.
\
cheers steve

It depends what you rev it to. OK if you limit revs. But this cam will give good power to well beyond 6500, a lot further than that if you have 1.5 rockers on it like me. :P

BTW, if running hi-lift cams with 1.5 rockers, watch you don't get the springs coil bound. S double springs or Metro singles will do this with (for example) an RE-13 or a Karcraft VP3, etc and 1.5 rockers. I use MiniSpares springs C-AEA526 which have 1 less coil and don't have a problem. But, they are 180lb, good for 8,000.... I guess you could leave the inners out though. :wink:
Author:  Chris [ Mon Mar 28, 2005 7:17 pm ]
Post subject: 
I pulledmy motor apart and the pushrod ball ends are stuffed. I haven't pulled the cam followers out yet. Anyone want an unknown hot cam....going cheap.
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