Date:         Wed, 15 Sep 1999 11:08:37 +1000
Reply-To:     Dom <dmoon@METZ.UNE.EDU.AU>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dom <dmoon@METZ.UNE.EDU.AU>
Subject:      Re: Align-boring?
Content-Type: text/plain; charset="iso-8859-1"

----- Original Message -----
From: Rico Sapolich <JKrevnov@AOL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, September 15, 1999 10:33 PM
Subject: Re: Align-boring?


>1/ The centerline(C/L) of the crank must be perpendicular to the C/L of
>the cylinders.  The only align-boring I've seen, on a VW case, was done
with
>a boring bar powered by a handheld drill motor.  Machinists call this a
>portable boring rig.  Would the proper method be to use a boring mill while
>registering the case to known surface?

There is nothing wrong with a portable boring rig. When set up by a VW
specialist they are quite often more accurate than an average industrial
mill.  I have seen these setups used for boring VW cases for aircraft.
Usually as well, the cam is bored at the same time as the mainshaft. Don't
be worrying about what is used to turn the bore, as long as it has the power
to do the job its just an electronic motor like any other. What is of
primary concern is the quality of engineering and experience which has gone
into the design, construction and set up of the rig itself

>     2/ I've heard as much as an 0.080" oversize used for the alignment
cut.

That from memory is the largest size you can go, at least with the older
aircooled cases and alot of rebuilders don't even like taking a case out
this far.

>Are bearing shells sized for this application readily available or is the
>oversize accommodated in some other manner?
 >    3/ The same questions apply to the camshaft case journals.

You can and must purchase bearings and journals which not only accomodate
the larger size created by the tunnel bore but the smaller size of the
crank/cam  if reground. These are probably more common than those with
original specs considering many engines that need to be pulled down this far
would require this type of work.