[T3] Heads

[Jim Adney]

On 7 Mar 2013 at 11:34, Adriel Rowley wrote:

> Cleaning up the pad for guests, moving the heads to a different spot,
> and noticed all had 375 ending part number which is not listed in the
> Russ parts book. Even more odd is one set has a G and the other a C
> (from a B F.I. engine), and neither is in parts book. I have another G
> head, and both G heads do not have the breather ports like Russ said
> they should have. What is going on? 

The numbers you see cast into the heads are NOT the part numbers for 
the heads. They are the part numbers for the castings which could 
have been machined into several different versions of heads in a 
separate operation at the factory. It's important to understand that 
VW had to have part numbers for "intermediate" parts in their 
production process. We never see those numbers listed on our parts 
lists, because they were not available for sale, they were only used 
for internal reference.

The same thing happens on engine cases. There are separate numbers 
cast into each side of the case, but neither number is the single 
number that VW sold a case under.

> Is it correct to use different part number heads on the same engine?
> Eventually I will have the ability to have two sets rebuilt; I do know
> I like to at least do one so I can put the ones Russ rebuilt on the
> shelf for now at least. 

It's best to just ignore the casting numbers, as those can change 
with design changes. Instead, look at the features: intake port 
dowell, spigot diameter, internal step, breather port, chamber 
volume, temp sensor boss. Chamber volume is the only one you can't 
see at a glance, but it's still important to get at least close 
within an engine.  

On FI engines, the 2 heads will always have different casting 
numbers, because only one casting had the boss for the temp sensor.

-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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