Re: [T3] engine diagnosis

["Keith Park" <topnotch@nycap.rr.com>]

<x-charset iso-8859-1>Jim,

how can it be possible to grind anything off the lobe and not significantly
reduce the lift??
and this grinding would be in addition to the wear already on the top of the
lobe.

Keith


----- Original Message -----
From: Jim Adney <jadney@vwtype3.org>
To: <type3@vwtype3.org>
Sent: Wednesday, October 31, 2001 9:38 PM
Subject: Re: [T3] engine diagnosis


> On 31 Oct 2001, at 20:05, Keith Park wrote:
>
> > I wouldnt use a reground cam eather... I mean, since the wear is on
> > the tops of the lobes, and regrinding can only make the lobes flatter,
> > and a flatter cam will affect performance (cut the top end power off)
> > how can this be an acceptable thing?? cam lobe design and shape is
> > critical to the desired performance of an engine so I wouldnt want a
> > misshapen one in there.
>
> I don't see any inherent problem with regrinding a cam, but of
> course you have to grind it all around to get the same lift, etc. If
> you had to grind too much off to get the profile right, then you could
> reduce the base circle enough that the lifters would be coming
> farther out of their bores, but I doubt if an extra 0.5mm would make
> much difference.
>
> > This is mentioning nothing of the surface hardening ...
>
> I would think this might be the big problem in any case. I suspect
> that there is some surface treatment that is important, so you have
> to trust that the person who did the grinding knew how to do this.
>
> -
> *******************************
> Jim Adney, jadney@vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
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