Re: Ur-Q hydraulic head conversion questions...

[JustaxPHX@aol.com]

> Interesting, This would indicate the 5 cyl. head underwent a different
>  development process from the 4 cyl. VW.  Check the differences between the
>  valve centers for a given cylinder.  During VW development this distance 
was
>  increased by about 1 mm to prevent cracking between the seats and as a
>  consequence the combustion chamber grew slightly in size (30 cc from 25 
cc).
>  Of course, the early VW heads didn't have the large valve sizes of the 
WR/WX
>  motors so the CC size may the same/similar to accommodate.

When the head comes back from the machine shop, I'll measure things more 
carefully.  My cc measurements were not exact -- I had to use a turkey baster 
instead of a calibrated burette (don't tell Paula!) -- but they were very, 
very close ... enough so that I suspect the chamber volumes are in fact 
identical.

>  The first VW heads to see these changes were the '83/'84 solid lifter GTI
>  heads then all the hydraulics.  At the same time some of the water/oil
>  passages were moved.

At first, I assumed that I would have to weld up some of the oil and coolant 
holes and then redrill them to the appropriate sizes, just as people do with 
the 4-cyl. VW heads when making this conversion.  But when I laid the Ur-Q 
head gasket on the head (no jokes, puh-leeze), it matched up almost 
perfectly.  There's one coolant passage on the MC head that is slightly 
larger than on the Ur-Q head but since the gasket covers the unneeded part of 
the opening, I don't see the need to make any changes just for this.

JG