<VV> Timing adjustments

[Mark Corbin]

As I was given to understand the "clock" casting symbol, it's a casting
number. The mold pattern is supposed to be replaced at certain intervals,
and the "clock" ticks off the number of times a pattern is used. The higher
the "clock" number, the more wear on the pattern and the more inaccurate
the casting. If you want to have a "fresh", accurate casting, look for a
low "clock" number.

-Mark


> [Original Message]
> Subject: Re: <VV> Timing adjustments
>
> I'm not sure how GM reconciled the fact that each casting with a 
> different timing number has the same part number. There are, of course, 
> a number of rear castings with different timing marks. How many 
> different part numbers are there - or are they ALL the same part number? 
> And if you ordered that part number  from a dealer which one would you 
> get? Obviously the 0-18 casting, as it would work with any of the others 
> (ex the turbo of course). Thinking about it I'm sure that it was never 
> an issue because the 0-16, 0-12, 0-8 etc castings would have never been  
> offered for sale in the parts department. A little awkward but just one 
> of those things.  Lon
>
> www.corvairunderground.com
>
> Helt at aol.com wrote:
> > In a message dated 6/22/08 3:17:59 PM Pacific Daylight Time, 
> > contactsmu at sbcglobal.net writes:
> >   
> >> Only the rear covers from the 60-63 stop at the 16 degree mark. - Jim  
> >> Davis
> >>
> >> Guess what?   I have a 60-63 rear cover.  I cleaned it and it only  
> >> goes to 16 - no if, ands, or buts. 
> >>     
> >
> > While just messing around in my shop yesterday, I came across two loose
rear 
> > engine housings in a box. Thinking that I would relocate them I
accidentally 
> > looked at their timing scales. To my surprise, cast right into the
housing was 
> > a 0 to 16 on one housing and also cast in the other was a 0 to 18
scale. 
> > Further checking of some engines identified several with the 0 to 18
scale. These 
> > must have been all for 140 hp engines although I can't prove it. Also
of 
> > interest is the fact that both types have a 3817672 number cast in
them. That means 
> > we have two different castings both using the same part number. Thus
the 0 to 
> > 18 must be a revised version.
> >
> > Of course we know the turbo engines all used a rivited-on timing scale
of 0 
> > to 20 with 0 to 24 being obtained by going to the end of the attached
piece.
> >
> > Regards,
> > Bob Helt
> >