Valve Spring question

[jdbubb@ix.netcom.com (Dan Bubb)]

----- Original Message -----
From: Rabbit16v <Rabbit16v@attbi.com>
To: Scirocco List <scirocco-l@scirocco.org>
Sent: Sunday, February 23, 2003 5:50 PM
Subject: Re: Valve Spring question


> Your right, Dan, it does depend on lift but the stiffer springs will
defend
> against valve float (I've had it happen with stock springs) and, like I
> said, seems to make a crisper feel on acceleration.

Well, like I said, if you're using radical cams that have high valve
accelerations, then you'll need the HD springs, but I don't think the Kent
278 falls into that catagory. It's a high performance street cam and is
unlikely to produce the power peak much higher than 6000 RPM, so no sense in
revving higher than 7K which the stock springs can handle.

>As long as you have it
> apart I'd DEFINEATELY install the HD springs especially when you never
know
> what the future holds!  You may want to spice it up a little more!  But,
if
> you are feeling the financial bind then I'd do what Dan did and stick with
> the old stock springs (although new stock springs may be a good idea??!).

You're putting words in my mouth. I didn't reuse the old springs! The
springs were new, but they weren't HD. The point to made here is that Colin
at TT ported the head. He installed the valve springs and cam and setup the
valve tension. So, he clearly felt the stock springs, properly shimmed, were
up to the task of handling the valve accelerations produced by the 274 cam.

> Although I don't see where stiffer springs will increase wear and lose
HP???
> More on this Dan??

All you have to do is turn the cam in the head by hand. You can feel how
much harder it is to turn. Harder to turn, more HP required. Stiffer
springs, more pressure on all the rubbing surfaces. If you're engine is
properly maintained the additional wear may be minimal, but it will wear out
the nose of the cam faster and will wear the bearings faster, particularly
during startup.

Clearly, if you're floating your valves, due to radical cam accelerations or
 extremely high revs then HD springs are required. In this case wear will be
extreme and Hp will drop in the toilet. A high lift cam will also require HD
springs due to coil bind.
I'm just saying I have a fairly radical 8V, makes 132 whp @ 6200 RPM, revs
clean to 7000RPM and uses stock valve springs setup by someone who should
know. HD springs are NOT a power adder if you don't need them!
Dan

>
> Dave
> ----- Original Message -----
> From: "Dan Bubb" <jdbubb@ix.netcom.com>
> To: <scirocco81@vwmail.net>; <scirocco-l@scirocco.org>
> Sent: Sunday, February 23, 2003 7:53 AM
> Subject: Re: Valve Spring question
>
>
> > Eric:
> > I think the need for the HD springs is driven by valve lift unless your
> > talking about a real high duration cam with radical valve accelerations
> > (which I don't think the Kent 278 is. Kent durations tend to be measured
> at
> > lower lifts, so their durations are generally higher for a comparable
> cam.).
> > I'm running a Schrick 274 with 11.3 mm lift using stock valve springs.
> > Controls the valves to 7000RPM. Colin at TT setup the cam and valve
> springs
> > initially and shimmed up the springs as much as reasonable without coil
> > bind. I looked, but couldn't find a Kent 278, so I don't know the lift
> > I don't know the actual limit, but I suspect anything over 11.3 lift is
> > going to need the HD springs.
> > No sense running a stiffer spring than you need. It's just wasting wear
> and
> > tear and lost HP.
> > Dan
> >
> > ----- Original Message -----
> > From: Eric S <scirocco81@vwmail.net>
> > To: <scirocco-l@scirocco.org>
> > Sent: Saturday, February 22, 2003 3:17 PM
> > Subject: Valve Spring question
> >
> >
> > >
> > > Hey all...planning on installing a Kent 278 cam on my 83 Rocco....can
> the
> > stock valve springs handle this cam?  Or do I need to upgrade to HD
> springs?
> > If so, what brands are reccomended, and who has the best prices?
> > >
> > > --
> > > Eric
> > > Northglenn, CO
> > >
> > > 81 Scirocco S (*TDI* swap and complete restoration in holding pattern)
> > > 81 Rabbit Truck LX Diesel (Waiting for BAE Turbo Install)
> > > 83 Scirocco Wolfsburg
> > > 91 Cabriolet (2.0 Crossflow 8v swap and mechanical rebuild in
progress)
> > >
> > > _______________________________________________
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> > > Scirocco-l@scirocco.org
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> >
> >
> >
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