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 Post subject: Double valve springs
PostPosted: Sat Mar 26, 2005 9:23 pm 
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1360cc
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Joined: Tue Mar 16, 2004 11:32 am
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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?


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 Post subject:
PostPosted: Sat Mar 26, 2005 9:24 pm 
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1098cc
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Joined: Sat Feb 05, 2005 9:02 pm
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Location: Leonay nsw
possibly but you dont get valve bouce


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 Post subject:
PostPosted: Sat Mar 26, 2005 9:54 pm 
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1360cc
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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?


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 Post subject:
PostPosted: Sat Mar 26, 2005 10:12 pm 
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1098cc
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Joined: Tue Apr 06, 2004 2:49 pm
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Location: Central Coast, NSW
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

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 Post subject:
PostPosted: Sat Mar 26, 2005 10:19 pm 
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1360cc
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mmm...nice...i dont think i have had a holden 8 that reved over 5500 - 6000.....


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 Post subject:
PostPosted: Sun Mar 27, 2005 6:07 am 
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Location: near Baulkham Hills, NSW
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.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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 Post subject:
PostPosted: Sun Mar 27, 2005 7:31 am 
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1360cc
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yea, I have Tuesday off work.....going to either Heritage or Karcraft for a buying spree :wink:


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 Post subject:
PostPosted: Mon Mar 28, 2005 5:51 pm 
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848cc
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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

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1973 south african mk3, 1275 +30 (1300), RE13 cam, hif44, mildy worked head with s sized valves, pulsar dizzy, 1.5:1 minispares forged rockers.


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 Post subject:
PostPosted: Mon Mar 28, 2005 6:57 pm 
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Location: near Baulkham Hills, NSW
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:

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R. :mrgreen:


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 Post subject:
PostPosted: Mon Mar 28, 2005 7:17 pm 
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1098cc
1098cc

Joined: Mon Nov 01, 2004 10:19 pm
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Location: Helensburgh NSW
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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