Re: [T3] Type engine longevity...Shad Laws

["Shad Laws" <shad@lnengineering.com>]

<x-charset iso-8859-1>Hello-

> >  My main concern with this engine is excellent longevity. I'm quite 
a tame
> > driver. I only want a little extra "get-up-and-go" for the purpose 
of at
> > least attempting to keep up with traffic and to not get run over 
when merging
> > into rush hour traffic. 
> 
> My interests are the same. To this end I do the following: 
> 
> Port and semi-hemi the heads to improve flow and allow me to use 
cheap 
> gas (which will not be getting any better in the future.)

Ack!  Never semi-hemi heads!!!  It is one of the WORST ideas that was 
EVER promoted in the VW world!

Sorry to react so strongly... this issue, unfortunately, is a pet peeve 
of mine.

Gene Berg didn't understand engineering.  He hadn't a clue about 
combustion engineering specifically.  The result is the worst VW head 
design ever created: the semi-hemi head.  I guarantee that it will ruin 
your flame speed (which is why they need so much more advance to run, 
like 38 instead of 28!).  It completely eliminates quenching.  It ruins 
thermal efficiency, which pulls down gas mileage and power output while 
kicking up engine temperatures.

Yuck!!!

And, since the chamber design is so horrible, it can't use as high of a 
compression ratio as a STOCK head before detonation.

I know, I know... Berg said 6.9:1 is good for semi-hemi, and stock 
heads are only good to 6.6:1, making semi-hemi an improvement.  This is 
absolutely false... consult ANYONE with combustion engineering 
experience and you'll see what I mean.

Keep the stock chamber.  Setup your engine to have 0.040"-0.060" deck 
height - no more!!!  You can do 0.035" if you blueprint it carefully (I 
often do it that way).  This will ensure EXCELLENT quenching ability, 
EXCELLENT thermal efficiency, etc.

And, it'll reduce the need for fancy gas, too :-).  Yes, I know this is 
the exact opposite of what Berg says... but he's flat-out wrong.


> Stick to 1600cc and a stock cam with stock rockers, add swivel-foot 
> adjusters.
> 
> Add full flow filter and a counterweighted crank. Balance everything.
> 
> Add case savers.
> 
> Enjoy the car!  ;-)

Sounds good to me, especially the last part! :-)

Take care,
Shad Laws
LN Engineering
http://www.LNengineering.com

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