The Home-made Home-builders Engine

Jerry Wass wrote:

Using a V-8 crankshaft would result in a weird firing order..(A 4 cyl
crank has 4 throws 180ºapart===-The V-8 has 4 throws spaced 90º apart.)
Jerry

I guess that brings us back to the shallow V4 on a in-line 4 crank.
While it would have a slightly odd firing order too, it's nothing that
can't be worked around.

A 20 to 40 degree offset would be enough to allow for a little cooling
air to pass up the middle without making the firing order to weird.

Tony

Lots of interesting ideas coming out. I've been doodling with them
using DeltaCAD. Trying to do an isometric of a V6 crankshaft is
enough to make you wanna go back to steam. Ditto for air-cooling.
Another ditto for valve trains.

Backing off, looking at the project from a different perspective, it
seems I'm more into details than basic concepts.

An exchange of messages with a fellow who actually works with the Lost
Foam process: when asked how fine I could go with details, he said to
go as fine as I like -- that producing the part was HIS task. Which
is kinda like money from home when you're trying to work out valve
train details. Some oil channels may have to be cleaned up with a
drill but the hole would still be there. Ditto for the fins. I spend
two hours on the thing before realizing I've got to do a lefty and a
righty.

Veeduber wrote:
Lots of interesting ideas coming out. I've been doodling with them
using DeltaCAD. Trying to do an isometric of a V6 crankshaft is
enough to make you wanna go back to steam. Ditto for air-cooling.
Another ditto for valve trains.

Backing off, looking at the project from a different perspective, it
seems I'm more into details than basic concepts.


Big picture stuff?

Start with a way to hold the cylinders in place without pulling the case apart.

Second to the fin heat limits, that's the biggest problem with VWs.
The cylinder (and head) hold downs just thread into the case.

cavelamb wrote:

Second to the fin heat limits, that's the biggest problem with VWs.
The cylinder (and head) hold downs just thread into the case.

That problem is solved with over sized case savers. They bite into a
much larger amount of the case and spread the torque around to more of
the case. It's amazingly rare for one of these to pull out.

Tony

Anthony W wrote:
cavelamb wrote:

Second to the fin heat limits, that's the biggest problem with VWs.
The cylinder (and head) hold downs just thread into the case.

That problem is solved with over sized case savers. They bite into a
much larger amount of the case and spread the torque around to more of
the case. It's amazingly rare for one of these to pull out.

Tony

I've used those - just makes sense.
But if one is designing an engine rated at over 80 hp, it would be a
good thing to address...

cavelamb wrote:
Anthony W wrote:
cavelamb wrote:

Second to the fin heat limits, that's the biggest problem with VWs.
The cylinder (and head) hold downs just thread into the case.

That problem is solved with over sized case savers. They bite into a
much larger amount of the case and spread the torque around to more of
the case. It's amazingly rare for one of these to pull out.

Tony

I've used those - just makes sense.
But if one is designing an engine rated at over 80 hp, it would be a
good thing to address...

An aluminum rather than a magnesium case and studs with a longer
threaded section would solve the problem. There are thousands if not
millions air cooled motorcycles and pulling a stud only happens when
some idiot over torques the stud. Even then, it's more common for the
stud to snap.

Tony

Veeduber schreef:
Lots of interesting ideas coming out.

Indeed, certainly to the eyes of this non-mechanic.
But few seem to answer your original search for an alternative for the
VW: a light engine of 40-60 HP, typical for a single seater.

Or what did I miss?
For that application, the Citroen 2-cylinder aircooled boxer seems one
of the rare alternatives; though it is smaller than the VW.

On Jun 2, 9:20*am, jan olieslagers
wrote:
Veeduber schreef:

Lots of interesting ideas coming out.

Indeed, certainly to the eyes of this non-mechanic.
But few seem to answer your original search for an alternative for the
VW: a light engine of 40-60 HP, typical for a single seater.

Or what did I miss?
For that application, the Citroen 2-cylinder aircooled boxer seems one
of the rare alternatives; though it is smaller than the VW.
----------------------------------------------------------------------------
"Or what did I miss?"

The Atlantic Ocean :-) The 2CV is an excellent engine, suitable for
single-seaters having low drag and a generous wing. But so few of
them were exported it is virtually unknown in the United States.

The engine received excellent coverage in auto magazines some years
ago when two engines were fitted to a vehicle which was then used as a
4WD for crossing the Sahara Desert.

Overhauling this engine is not for the inexperienced. It uses
specially shaped pistons which must be installed properly or the valve
will contact the piston, which usually results in a trashed engine.

-Bob

Veeduber schreef:
On Jun 2, 9:20 am, jan olieslagers
wrote:
Veeduber schreef:

Lots of interesting ideas coming out.
Indeed, certainly to the eyes of this non-mechanic.
But few seem to answer your original search for an alternative for the
VW: a light engine of 40-60 HP, typical for a single seater.

Or what did I miss?
For that application, the Citroen 2-cylinder aircooled boxer seems one
of the rare alternatives; though it is smaller than the VW.
----------------------------------------------------------------------------
"Or what did I miss?"

The Atlantic Ocean :-)

OK Bob, thanks for the reminder...
Still, you asked for a 40-60 HP engine
and all and sundry came up with 80-100 hp ideas,
that's my concern now.

Seems the US market has a hole, indeed, between
the 30-40 HP range and 80HP upwards.
Europe has _some_ offer there,
but not too much and indeed each with its limitations.
And we badly want information about Asian offerings,
as you already pointed out before.

jan olieslagers wrote:
Veeduber schreef:
On Jun 2, 9:20 am, jan olieslagers
wrote:
Veeduber schreef:

Lots of interesting ideas coming out.
Indeed, certainly to the eyes of this non-mechanic.
But few seem to answer your original search for an alternative for the
VW: a light engine of 40-60 HP, typical for a single seater.

Or what did I miss?
For that application, the Citroen 2-cylinder aircooled boxer seems one
of the rare alternatives; though it is smaller than the VW.
----------------------------------------------------------------------------

"Or what did I miss?"

The Atlantic Ocean :-)

OK Bob, thanks for the reminder...
Still, you asked for a 40-60 HP engine
and all and sundry came up with 80-100 hp ideas,
that's my concern now.

Seems the US market has a hole, indeed, between
the 30-40 HP range and 80HP upwards.
Europe has _some_ offer there,
but not too much and indeed each with its limitations.
And we badly want information about Asian offerings,
as you already pointed out before.



Rotax - 503 or 582 (618).

Yes, they are two stroke engines.

When installed and operated correctly they are very reliable.


They run turbine smooth, and the power to weight ratio is tops.