1600 -> 1641

"Tim Rogers" > wrote in message
...
>
> The heads that I've already purchased are Aircooled.Net's level 3 stock VW
heads
> which have less porting and smaller valves than the more radical level 2's
& 3's.
>
>

..................Whoops. I meant to say that the level 2 and level 1 are
more radically ported and have larger valves than the level 3 ones that I
have.

Tim Rogers wrote:
>..............What are your thoughts on the practicality of a 88x74 type 1
> with machine-in cylinders and a counter-balanced crankshaft?
> I understand
> that the heads won't allow sustained power usage past a certain level
> without getting too hot but I'm a lead foot and it would be nice to be able
> to out-accelerate those pesky SUV's & minivans. I'd like to stay with the
> Jetronic FI and stock exhaust system and maybe a mild aftermarket cam grind
> like WebCam's 118. I've never read much about a set-up like this and need
> some guidance :-)

---------------------------------------------------------------

The 88x74 is a very practical engine. The 74mm crank is the largest
that can use stock-length connecting rods, making it less expensive --
and more reliable -- than the more popular sizes endorsed by
Conventional Wisdom.

But you're comparing apples to oranges when you link the 70 year old VW
design to a modern, water-cooled four-banger, some of which are not
much bigger than a shoe box but can crank out an honest 140hp... and
still give you a quarter-million miles of trouble-free service AND
30mpg. Tackle one of those with a bug and you've just been suckered
-- you're playing the other man's game. If you want to win you need to
skew the odds in your favor, such as playing in the dirt. Take any
modern vehicle off-pavement -- including most SUV's -- and all they'll
see of you is tail-lights.

Studying the differences between the early Porsche and the VW will help
you understand the VW's thermal limitations. It should also make it
clear those limitations are inherent in the design. If you need more
SUSTAINABLE horsepower you need more fin area and better exhaust
valves. Of course, more fins won't fit under your tin-ware and better
valves won't fit your heads. You can pull as much PEAK power out of
the thing as you're willing to pay for but only for a couple of runs.


The satisfaction of dusting a suburban housewife in her minivan -- who
probably doesn't even know she's just been blown-off -- will make you a
member of the Engine of the Month Club, which is what all those
after-market retailers are hoping for.

Time to start thinking for yourself. All those wunnerful folks trying
to sell you all that kewl stuff aren't doing you any favors.

-Bob Hoover

> wrote:

> Studying the differences between the early Porsche and the VW will help
> you understand the VW's thermal limitations. [...]

What of using aluminum, nickelsil plated cylinders, better heads and a
full-flow oil system? Won't that bring about better cooling and performance?

> wrote in message
oups.com...
>
> The 88x74 is a very practical engine. The 74mm crank is the largest
> that can use stock-length connecting rods, making it less expensive --
> and more reliable -- than the more popular sizes endorsed by
> Conventional Wisdom.
>
>

................Thanks Bob. That's what I was hoping to hear.


>
> But you're comparing apples to oranges when you link the 70 year old VW
> design to a modern, water-cooled four-banger, some of which are not
> much bigger than a shoe box but can crank out an honest 140hp... and
> still give you a quarter-million miles of trouble-free service AND
> 30mpg. Tackle one of those with a bug and you've just been suckered
> -- you're playing the other man's game. If you want to win you need to
> skew the odds in your favor, such as playing in the dirt. Take any
> modern vehicle off-pavement -- including most SUV's -- and all they'll
> see of you is tail-lights.
>
>

................A bug's 1800 lb curb weight with weight transfer to the
driving wheels during acceleration can provide the basis for an eye-opening
lesson for those @#$%^&*! Chevy Tahoes and Jeep Grand whatevers. All you
need is maybe 90(?) horsepower and a short distance so that the head temp
gauge stays under 400 deg while the lesson is being administered. I'm well
into my fifties now and I can only pretend to be what I once was by
humiliating some of these thirty year old losers who think that their $40k
has bought them supremacy of the road.


>
> Studying the differences between the early Porsche and the VW will help
> you understand the VW's thermal limitations. It should also make it
> clear those limitations are inherent in the design. If you need more
> SUSTAINABLE horsepower you need more fin area and better exhaust
> valves. Of course, more fins won't fit under your tin-ware and better
> valves won't fit your heads. You can pull as much PEAK power out of
> the thing as you're willing to pay for but only for a couple of runs.
>
>

............I don't need more sustainable horsepower than is needed to propel
my 1800 lb. bug down the road at about 75 mph. You've posted how much that
is in the past, it's a modest number I recall. As for peak horsepower, yeah
I admit that I want more than I'm getting but my wants are fairly modest.
Maybe 90-100 hp with an rpm limit of 5,000(?) and a peak head temp of 400
deg F. My dad was a pilot and I know what you're supposed to do when you see
that needle reach 12 o'clock on the CHT when you're running aluminum heads.


>
> The satisfaction of dusting a suburban housewife in her minivan -- who
> probably doesn't even know she's just been blown-off -- will make you a
> member of the Engine of the Month Club, which is what all those
> after-market retailers are hoping for.
>
>

............Oh Bob. Trust me, some of them know exactly what you've done to
them and they don't like it. I've been saluted by some of the classiest
looking female executives that you'd ever want to avoid at a congested
on-ramp. My engine is still doing pretty good so far even though it still
has a pair of Berg semi-hemi heads on it since it was built almost 20,000
miles ago. The end play is good and there's no varnish in the rocker arm
galleries.The oil pressure is still running about 15 psi at idle when it's
good and hot and there's no noticeable oil loss on the ground or out the
exhaust between 3,000 mile oil changes.


>
> Time to start thinking for yourself.
>
>

...............I'm trying Bob. But it isn't that easy with a wife who's going
through menopause and three nearly grown kids who are trying to keep me from
spending their inheritance. They all want to do my thinking for me these
days.

johnboy wrote:

> What of using aluminum, nickelsil plated cylinders, better heads and a
> full-flow oil system? Won't that bring about better cooling and performance?
-----------------------------------------------------------

Nope.

Only 17% of your waste-heat 'budget' appears in the barrels. The
reason Porsche went to aluminum jugs was so they could devote more of
the cooling air to the heads. That is, the use of aluminum jugs was
one PART of an entire system of modifications needed to pull more power
out their engine and have it fit in the same chassis.

'Full-flow' doesn't make much sense. I assume you mean a full-flow oil
filtration system... which still doesn't make much sense because
filtering the oil doesn't have anything to do with cooling.

But if you meant adding extra oil cooling capacity... no again. To
produce more power without shortening the engine's service-life you
don't want the heat to get into the oil to begin with.

The latter point is one of the most commonly mis-understood
characteristics of air-cooled engines, which you often hear described
as 'oil cooled.' They're not. Indeed, ALL automobile engines are
'air-cooled' in that they must couple their waste heat to the
atmosphere. The lubricating oil serves exactly the same function in a
water-cooled engine as in an air-cooled engine, the only difference is
that the waste heat that appears in the oil of an air-cooled engine
must be coupled directly to the atmosphere, as opposed to being coupled
to an intermediary coolant as is the case with a liquid-cooled engine.

At high levels of output you're going to produce more waste heat. Most
of it -- about half -- blows right out the tail pipe but some appears
in the heads, barrels, piston and valves AFTER WHICH some is
transferred to the lubricating oil. The principle areas of transfer
are via the underside of the piston and the area of the cylinder-head
immediately adjacent to the exhaust valve(s).

The problem here is two-fold, the first being that oil is not an
especially good coolant, the second is that the RATE of transfer is a
function of the surface area, the rate of coolant-flow and the nature
of the coolant itself. Simply clapping on a bigger cooler addresses
only the heat that has ALREADY gotten into the oil, which is only a
small part of the cooling equation.

The VW's heads and jugs were designed for a rather modest level of
waste-heat management. When you generate waste-heat at a greater rate
than those designed limits you end up with excessively high
temperatures in your jugs and the areas adjacent to the exhaust valves
-- temperatures so high they COOK the oil rather than simply transfer
the heat. The remaining oil does pick up a lot a heat but those areas
are still hotter than they should be, resulting in greatly accelerated
wear and possible detonation.

But it looks good on paper, right? :-) Just give the man your money,
bolt on an oil cooler the size of a barn door and bingo! No worries.
Unfortunately, all you've done is treat the SYMPTOM. The problem --
the excessively high temperatures -- are still there.

Thermodynamics does not respond to Convential Wisdom. Any more than
engineering responds to the Democratic Process. The fact a majority of
your buds -- and all of the folks trying to sell you stuff -- say a
bigger oil cooler is the way to go doesn't mean it is.

-Bob Hoover

So nice to see posts from the RAMVA guys - blast from the past. Sorry I don't
have time to subscribe at the moment.

Take care,
Dave.
UK VW Type 3 & 4 Club
http://www.hallvw.clara.co.uk/
------
"Tim Rogers" > wrote in message
...
> "Tim Rogers" > wrote in message
> ...
> >
> > The heads that I've already purchased are Aircooled.Net's level 3 stock VW
> heads
> > which have less porting and smaller valves than the more radical level 2's
> & 3's.
> >
> >
>
> .................Whoops. I meant to say that the level 2 and level 1 are
> more radically ported and have larger valves than the level 3 ones that I
> have.
>
>

All this, and i was only asking about an extra 41cc heheheh
Thanks for the input chaps. I think i'll just stick with what i've got.
Maybe pop the money somewhere else into the car......

What about those Flame thrower coils???? Just got a bosch bluey.
Make any difference? power/mpg? etc

cheers
ant


"Ant" > wrote in message
...
>
> Hello,
> I can remember writing about this a while ago, but thought i'd ask again
> as my minds a bit naff.
>
> I have a 1600cc AB engine (with Engle 110, 1500 g/box and 32/36 Weber dual
> Choke). I've seen that you can buy a piston kit to make it 1641cc.
> Sounds good as i understand that you dont need to start having things
> bored out/machined.
>
> Questions
> 1) Will i notice a difference in speed/BHP? will a whopping 41cc's make
> any difference?
> 2) Would it be ok with the cam shaft and existing weber.
> 3) should it be ok, is there anything else i would need to buy? or is
> everything in the kit? (kit comprises of barrels, pistons, clips and
> pins - ooh yes and the rings)
>
> Money is a bit tight, so as much as i would like twin beefy webers i cant
> afford it (other bits needing sorting on car)
>
> Cheers fellow bug'ers - ant
> UK - 1966 'Mellow Yellow' Beetle
>
>
>

"Ant" > wrote

> What about those Flame thrower coils???? Just got a bosch bluey.
> Make any difference? power/mpg? etc

In my most humble opinion, your money would be best spent on a proper
distributor and a simple electronic ignition - the kind in which you can
replace the pickup with regular points on the road in case it flakes out.
The most important part is proper timing and transitions. You will be MUCH
happier without the consequences of screwed-up timing such as bad mileage,
stumbling, overheating (lean) or fowling (rich).

You will NOT make your engine go fast with cheap bolt-on parts, but you
might be downright amazed how quick a properly tuned and running ACVW can
be - compared to the state of tune of most ACVWs on the road

Bob, is my basic assumption that the greater the air flow (cfm), the
better then?

href="http://albums.photo.epson.com/j/AlbumIndex?u=4025706&a=30209382&vt=vp">Den's
1977 Puma</a>

Ant wrote:
>
> What about those Flame thrower coils???? Just got a bosch bluey.
> Make any difference? power/mpg? etc
>
------------------------------------------------------

More bull**** for the Kiddie Trade.

Electrically, the blue Bosch coil is exactly the same as the black
Bosch coil. The difference is that the older coil (ie, black) was
manufactured using traditional tar, Bakelite and varnish; the newer
blue coil is manufactured using modern plastics and SHOULD be more
durable at high temperatures.

But as for all the claims of 'hotter' sparks, more energy and so
forth... it's all bull****. Why? Because the limiting factor is not
the coil but the POINTS.

Your points are an electrical switch. The initial in-rush current to
the coil approaches 10A., quickly dropping off as the magnetic field
around the coil builds up. Average electrical load is about 3A.

However much current the coil is designed to use must pass through the
points. To use a coil having lower internal resistance (ie, that draws
more current) you'll have to also use bigger points.

If you don't increase the amount of energy going into the coil you
won't see any increase in the energy coming out of it. Some
after-market coils having a different windings-ratio, meaning they
should show a higher output voltage, but if the input current is the
same, bumping up the output voltage means the output CURRENT must fall.


Electrically, the stock VW ignition system, which is based on the
Kettering patents of 1919, is about as complicated as a flashlight.
Like all Kettering systems the output begins to 'droop' as the rpm
increases. This reflects the decrease in the amount of time the points
are closed -- when current can flow into the coil and build-up the
magnetic field. When the points open, the field collapses. The rapid
collapse of the magnetic field is what generates the high voltage
output.

All modern ignition systems use something OTHER than a mechanical
switch (ie, your points) to control the flow of current to the coil,
typically a husky transistor that can carry more current than the
original points.

If you want to improve your ignition system simply replace the
mechanical points with a solid-state switch, such as the Pertronix or
Compu-Fire. If you want to run higher rpms and a higher compression
ratio, install a Capacitance Discharge ignition module.

But if all you want is one of those kewl blue coils that all the
magazines say are so good, buy a can of spray paint.

-Bob Hoover