On Jul 20, 1:22*pm, Reggie wrote:

*Is there a larger diam stem, Porsche, valve, spring, keeper,guide
assy that could
be placed in *the VW head *???

Or even hot rod "kiddie" (after market) stuff ......
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Dear Reggie,

Since money can buy anything except poverty I'll bet you already know
the answer :-)

Of course you can buy Porsche-type heads for your VW conversion. The
going price is about $5k USD per pair since they have to begin with a
new casting. But for those rolling in dough the usual procedure is to
simply buy a spare set of heads (about $125 each and you'll need two)
and simply swap heads when the engine has accumulated about 200
hours. The work will take about four hours for a first-timer, as
little as one hour for someone more experienced. You then have 200
hours to inspect & overhaul the 'down' heads, which should cost you
$28 per head [2008 prices] assuming you have the necessary tools. The
tooling and procedures are described in prior articles (with
pictures!).

The 200 hours is not carved in stone. A leak-down test, which is done
with the engine assembled, will tell you if you need to pull the head
and do the wiggle test. Some engines will soldier on in the high-
green for 500 hours or more, depending on the manner and conditions
under which they are flown. (Engines fitted with a full-flow oil
filtration system do much better than those withoiut.)

Typically, you will see the end-float opening beyond spec somewhere
between 500 and 750 houirs, indicating it is time to replace the
bearings on the lower end. A full set of bearings is about $60USD
[2008 prices]. As a general rule you can replace the mains twice
before it becomes necessary to re-machine the thrust bearing carrier's
web and when THAT falls out of spec you may buy a Universal
Replacement Crankcase [about $400 USD -2008 prices] and begin the
cycle anew.

The above is NOT a description of something new or unusual. The
Volkswagen engine was DESIGNED to be maintained in the manner
described. With regard to maintenance, the only major difference
between flying and vehicular use is that the higher output required of
an engine converted for flight dictates the need to perform such
maintenance about twice as frequenty.

While you can always buy a solution to a problem, the method described
above is based on investing in yourself, acquiring the skills and
tools needed to properly maintain your engine. Not only will you find
there's a lot of flying in 200 hours, there is a lot of satisfaction
being able to do so entirely upon your own merits as a mechanic.

-R.S.Hoover