Re: 4-cylinder engine

[bbell@csn.org (Bruce Bell)]

>
>I have heard, read and seen pictures of VW rods and Audi rods. The Audi rods
>are reputed to be far superior and are outwardly different, visually.

Yep.

>In a magazine article that included pictures of each, the writer observed
>that the VW rods were rather "normal", where the Audi rods were referred
>to as "beautiful" and a "work of art". I believe this article was about
>building high-perf VW engines and that the point of the rod comparison
>was that the VW rods needed considerable ($) reworking for high-perf use,
>but the Audi rods were much stronger and needed virtually no reworking or
>prep. So, while the blocks and other parts may be similar or even the same,
>the rods are not!The Audi rods were, if I remeber right, a bolt-in part
>in place of the VW rods for the VW motor being built.

The Audi Rods, are not a bolt in replacement part for the "VW rods" because
1) the rod journal is larger on the "Audi", 2) the VW fits a 22mm vs 20mm
wrist pin and 3) the VW rod is 136mm in length versus the Audi's 144mm length. 

The 1715cc VW engine of 1981 had those ugly rods to which you refer.
However, beginning in 1983 when the bore was increased to 81mm (GTI engine)
VW started using the "Audi rods". Part of the promotional package for the
GTI was that pistons and rods were lighter and that the rods were from Audi.
Note that the '83 GTI was the first, in the US anyway, VW that used the
144mm Audi rods.  It is interesting to note, that Audi 5 cyl. engines with
the 79.5mm bore have the same rod journal size (bearings are the same part
#) as the VW's with the sorter "ugly" rods.

There is NO visible or measurable difference between the pistons and rods in
my son's '83 GTI and those in my '87 4000CSQ, other than normal set
up-tolerances.  


Bruce

bbell@csn.org