Question on LUMPY idle (was: Lightened Flywheels)

[amalventano1@comcast.net (Allyn)]

lumpy idle is when you can tell the engine is slowing down/speeding up between firing, kinda like a
harley where you think its gonna stall between each fire. Cams can cause this due to higher
duration/lift, its not getting the smooth opening/closing its used to. Also higher duration cams
have more overlap, adding to the blub-blub sound. cams combined with lightened flywheel will just
make this worse (well, its not that bad, i get a chubby every time i fire up the rieger, heh).
Al

Allyn Malventano, ETC(SS), USN
87 Rieger GTO Scirocco 16v (daily driver, 170k, rocco #6)
86 Kamei Twin 16V Turbo Scirocco GTX ('it has begun', rocco #7)
87 Jetta 8v Wolfsburg 2dr (daily driver, 260k, 0 rattles, original clutch, driveshafts, wheels :)

----- Original Message -----
From: "Cory Langford" <cory.langford@icbc.com>
To: "scirocco" <scirocco-l@scirocco.org>
Sent: Monday, March 25, 2002 4:20 PM
Subject: Question on LUMPY idle (was: Lightened Flywheels)


>
>
> Okay.  This may sound like a stupid question to some, but live with it
> :)
>
> The old beater just got munched again (scirocco vs Cube van, guess who
> won).  This time the insurance decided not to fix it (been hit 4 times
> in 3 months) so they cashed me out on it.
>
> Still needing a car to drive while the turbo project is being worked on,
> I ran out and bought an '83 cheap (another beater - but potential to fix
> up)
>
> Here is the question:
>
> It has what I would call a very "lumpy" idle.  It starts on first crank,
> and it is quiet as hell starting.  But once idling it tends to sound
> "lumpy" and a little loud.  Loud is due to that Eurosport exhaust that
> was put into the thing by the P.O., unfortunately he did not know what
> was done to the engine as he only had it a short time.
>
> So what causes this LUMPINESS?  It is not the "roll" you get sometimes
> when the engine is older, or miss adjusted.  It really sounds lumpy (now
> that I know what that sounds like first hand).
>
> My first thought was a cam.  I did not realize that a lightened flywheel
> would do this.
>
>
> Another question (to make this long winded):
>
> It has Jammex Struts/Shocks and Springs installed on it.  It seems to be
> sitting rather low. (stock 13 tarantulas seem to just fit into the wheel
> wells).  Anyone have any opinions on Jamex stuff?  Is it work keeping or
> swapping out for stock springs and  Bilsteins I have on the beater?
>
>
> --
> Cory Langford
> '86 Oettinger turbo project
> '83 better beater...
> '82 beater (to be dismantled)
>
> _______________________________________________
> Scirocco-l mailing list
> Scirocco-l@scirocco.org
> http://neubayern.net/mailman/listinfo/scirocco-l