what every boy needs - yeah seriously

..
On Jan 8, 12:34*pm, " wrote:
What IS needed are aluminum head-castings having twice as much fin-
area as what's presently available.
------------------------------------------------------------------

We need a CASTING because we need the DRAFT that goes with it.

Come up with a set of fins that leaves a clean impression in our
casting media and we'll automatically get a set of fins that does a
dandy job of coupling heat to air being forced down through, over,
passed an' whatever THROUGH those fins.

Now all we gotta do is come up with ENOUGH of those fins... as
determined by their area... to deal with the anticipated amount of
HEAT and we're on the road to Rio. Or where-ever.

-R.S.Hoover

....an' finally...
I gotta memory chip in my hand here that sez 'T2,' meaning it's got
mostly Teenie Two drawings on it. It is a two gigabyte chip, which
means it can't be ALL T2 stuff. Sure enough, one of the folders sez
'Engine.' Pull that up and there's about a dozen sub-files, one of
which is 'HEADS.' Pull THAT up and you got fifty drawings of VW
cylinder heads, a lot of which is bumpf... three nearly identical
drawings of the same thing representing sequential SAVE's so as not to
lose anything as I work on the drawing(s) (...which is a pretty
boring way to pass the day.... but a royal ****er to spend a whole day
doing a drawing only to LOSE the sonofabitch because I hit the wrong
button or whatever, hence lotsa copies of... whatever).

So why mention it? Because others may find some of the drawings of
interest. So provide me with a VALID address and I'll sendm' to you,
gratis.

-R.S.Hoover

what else???

Stealth Pilot

As VeeDubber has pointed out the heads are the limiting factor for HP.
The VW has other problems but workarounds for them have been found,
even if they are inelegant ones.

I've looked at and sawed up more VW heads, and sketched out more ways
to improve them, than a sane person would be willing to admit to in
public. If one insists on dual plugs and a true improvement (other
than just more cooling capacity) then I haven't been able to come up
with a solution - unless one also moves the camshaft and spaces the
lobes out to match the bore spacing. This requires a new crankcase as
well.

Doing this opens up MANY options using inexpensive off the shelf
parts. I'm thinking a split head, like Scat makes, but following the
layout of a Porsche 356 might be a good starting point?

Oil-cooled VW heads are an option I have not heard anyone talk about
for aircraft use. I've not done any math related to this option but
it seems to be a viable one. Anyone actually tried the methods used
by Porsche tuners on a VW?
========================
Leon McAtee

wrote:
what else???

Stealth Pilot

As VeeDubber has pointed out the heads are the limiting factor for HP.
The VW has other problems but workarounds for them have been found,
even if they are inelegant ones.

I've looked at and sawed up more VW heads, and sketched out more ways
to improve them, than a sane person would be willing to admit to in
public. If one insists on dual plugs and a true improvement (other
than just more cooling capacity) then I haven't been able to come up
with a solution - unless one also moves the camshaft and spaces the
lobes out to match the bore spacing. This requires a new crankcase as
well.

Doing this opens up MANY options using inexpensive off the shelf
parts. I'm thinking a split head, like Scat makes, but following the
layout of a Porsche 356 might be a good starting point?

Oil-cooled VW heads are an option I have not heard anyone talk about
for aircraft use. I've not done any math related to this option but
it seems to be a viable one. Anyone actually tried the methods used
by Porsche tuners on a VW?
========================
Leon McAtee



Fin area of the heads is only the first in a long line of limitations.

To my thinking, the next is the cylinder hold down studs (that don't
go all the way across).

The next would be valve seats (hydraulic lifters won't help there).

Valve size would have to be enlarges to let the engine breathe.

Six or eight places later comes the thrust bearings. At some output
level one would have to take power off the fat end and install larger
thrust bearings.

In the end, it makes a wonderful 40 horsepower motor.

"cavelamb" wrote in message
...
wrote:
what else???

Stealth Pilot

As VeeDubber has pointed out the heads are the limiting factor for HP.
The VW has other problems but workarounds for them have been found,
even if they are inelegant ones.

I've looked at and sawed up more VW heads, and sketched out more ways
to improve them, than a sane person would be willing to admit to in
public. If one insists on dual plugs and a true improvement (other
than just more cooling capacity) then I haven't been able to come up
with a solution - unless one also moves the camshaft and spaces the
lobes out to match the bore spacing. This requires a new crankcase as
well.

Doing this opens up MANY options using inexpensive off the shelf
parts. I'm thinking a split head, like Scat makes, but following the
layout of a Porsche 356 might be a good starting point?

Oil-cooled VW heads are an option I have not heard anyone talk about
for aircraft use. I've not done any math related to this option but
it seems to be a viable one. Anyone actually tried the methods used
by Porsche tuners on a VW?
========================
Leon McAtee



Fin area of the heads is only the first in a long line of limitations.

To my thinking, the next is the cylinder hold down studs (that don't
go all the way across).

The next would be valve seats (hydraulic lifters won't help there).

Valve size would have to be enlarges to let the engine breathe.

Six or eight places later comes the thrust bearings. At some output
level one would have to take power off the fat end and install larger
thrust bearings.

In the end, it makes a wonderful 40 horsepower motor.


The cylinder hold down studs have always been my first concern as well.

In the end, I completely agree that it is a great, inexpensive 40 horsepower
alternative for a single place aircraft.

Peter

On Jan 8, 12:37*pm, Stealth Pilot
wrote:
veedubber and others
the venerable old VW engine conversion is quite usable.

if you were to take all the lessons learnt from all the engine
building done so far and apply them to a new engine design, what would
the new engine design look like?


A Subaru?

Monk wrote:
On Jan 8, 12:37 pm, Stealth Pilot
wrote:
veedubber and others
the venerable old VW engine conversion is quite usable.

if you were to take all the lessons learnt from all the engine
building done so far and apply them to a new engine design, what would
the new engine design look like?


A Subaru?

We had one running direct drive - at 40 to 50 hp.

But to use the full potential it needs a proper PSRU -
along with all the extra weight that implies.
(Ever try to prop a motor with a PSRU on it?_

On Jan 8, 3:56*pm, Monk wrote:

A Subaru?
---------------------------------------------------------------------------------------------------

Not bad. But it's going to come down to the Bottom Line. And in
that regard, the individual heads are the winners. Why? Because we
can do the machining ourselves.

First off, we can forget about lost-foam or anything more exotic than
green-sand, simply because there aren't enough of us. So we stick to
standard, readily available valves, valve guides, valve seats and
studs. The fins make the castings pretty tricky but if it was easy
you would have seen it years ago.

There's a couple of directions we can't go but if we borrow a page
from the Corvair we can position our exhaust stack just about anywhere
and still have a good seal. Most of us have MIG, which means we can
do the stack-extensions. And since it's a new casting we can provide
the boss for the hold-down bolt.

Here again, borrow a page from the Corvair (or from GM) and we end up
with a 'rocker arm' that actually works. The tricky bit is that it
does NOT need to be aligned on a shaft... we can literally put a valve
anywhere there is room. And that means at any angle as well.

Domed or hemi-shaped chamber won't buy us anything. I'm pretty sure
of that, based on some work I did in that area about 30 years ago.
But that's actually to our advantage. By keeping the combustion
chamber simple we keep our valve-train geometry simple. AND YES, we
run juicers.

Exhaust outlet to the stack is probably a rectangle, as with the
Porsche. We put the wiggles into the exhaust stacks, which we make
out of Monel or whatever, secured with that bolt we stole from the
Corvair.

So we make a L-head and an R-head; mirror images. We do the best we
can with the fins but recognize our limitations and leave the most
difficult of them as CUT fins: Rather than try to cast perfect fins in
a couple of high-risk areas, we settle for a quarter-inch bar of
aluminum that's configured for easy SAWING, which we do as part of the
flash clean-up.

-R.S.Hoover

wrote in message
...
On Jan 8, 3:56 pm, Monk wrote:

A Subaru?
---------------------------------------------------------------------------------------------------

First off, we can forget about lost-foam or anything more exotic than
green-sand, simply because there aren't enough of us. So we stick to
standard, readily available valves, valve guides, valve seats and
studs. The fins make the castings pretty tricky but if it was easy
you would have seen it years ago.

So we make a L-head and an R-head; mirror images. We do the best we
can with the fins but recognize our limitations and leave the most
difficult of them as CUT fins: Rather than try to cast perfect fins in
a couple of high-risk areas, we settle for a quarter-inch bar of
aluminum that's configured for easy SAWING, which we do as part of the
flash clean-up.

-R.S.Hoover

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

I've alway thought it would be more practical to CNC saw all the cooling
fins. Seems a bit extreme at first glance, but if you go to the time or
expense to fabricate patterns to cast the heads, we must be talk about doing
more than just a couple of sets. So the programming cost might well be worth
the cooling efficency of extremely detailed cooling fins.

On Jan 8, 10:30*pm, "Maxwell" #$$9#@%%%.^^^ wrote:
wrote in message

...
On Jan 8, 3:56 pm, Monk wrote:

A Subaru?

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

First off, we can forget about lost-foam or anything more exotic than
green-sand, simply because there aren't enough of us. *So we stick to
standard, readily available valves, valve guides, valve seats and
studs. *The fins make the castings pretty tricky but if it was easy
you would have seen it years ago.

So we make a L-head and an R-head; mirror images. *We do the best we
can with the fins but recognize our limitations and leave the most
difficult of them as CUT fins: Rather than try to cast perfect fins in
a couple of high-risk areas, we settle for a quarter-inch bar of
aluminum that's configured for easy SAWING, which we do as part of the
flash clean-up.

-R.S.Hoover

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

I've alway thought it would be more practical to CNC saw all the cooling
fins. Seems a bit extreme at first glance, but if you go to the time or
expense to fabricate patterns to cast the heads, we must be talk about doing
more than just a couple of sets. So the programming cost might well be worth
the cooling efficency of extremely detailed cooling fins.

I disagree, sand casting would be easier than milling from solid
block. Just sculpt your head out of wax cover with sand and pour your
casting. A little grinding here and there and there you have it. OK,
not that simplistic, but you get the gist.