Q: can a Continental A65-8

be tuned to make 100 HP?

On Apr 16, 8:22*am, "oilsardine" wrote:
be tuned to make 100 HP?

Probably. But finding a prop to spin at 4500 RPM might be a
problem :-)
========================
Leon McAtee

"oilsardine" wrote in message
...
be tuned to make 100 HP?

Stick a supercharger on it with fuel injection, and then a bigger oil pump
and oil cooler to get rid of the exxtra heat, and no problem.

How long it will last is another story. If you set it to not boost too
high, it might last a thousand hours.
--
Jim in NC

On Apr 16, 2:50*pm, "Morgans" wrote:

How long it will last is another story. *If you set it to not boost too
high, it might last a thousand hours.

I doubt it. They're an 1800-hour engine that almost always need top
overhauls well before then, sometimes before mid-time. Boosting it
would overstress already-weak valves and it wouldn't go too far at
all. And with the traditionally low oil pressure these things have,
the bottom ends wouldn't last too long either. The crank was not
nitrided and wears rather rapidly anyway.
The same basic engine was boosted to 75 hp (A-75) using a
higher redline and heavier piston pins and a slightly larger carb
venturi and main jet. They got 80 hp (A-80) by raising the compression
to 7.55:1 from 6.5 as well as the higher redline and bigger carb. And
that's about as much as they dared get from 140 cubic inches with the
engine being as light as it is.

Dan

hmmm....
thought to replace my Revmaster with this Conti, but now, mybe I better stay
with the VDub?


schrieb im Newsbeitrag
...
On Apr 16, 2:50 pm, "Morgans" wrote:

How long it will last is another story. If you set it to not boost too
high, it might last a thousand hours.

I doubt it. They're an 1800-hour engine that almost always need top
overhauls well before then, sometimes before mid-time. Boosting it
would overstress already-weak valves and it wouldn't go too far at
all. And with the traditionally low oil pressure these things have,
the bottom ends wouldn't last too long either. The crank was not
nitrided and wears rather rapidly anyway.
The same basic engine was boosted to 75 hp (A-75) using a
higher redline and heavier piston pins and a slightly larger carb
venturi and main jet. They got 80 hp (A-80) by raising the compression
to 7.55:1 from 6.5 as well as the higher redline and bigger carb. And
that's about as much as they dared get from 140 cubic inches with the
engine being as light as it is.

Dan

On Apr 16, 5:54*pm, wrote: question about
a-65-8.

The 80-hp version is cranky because the pistons are so heavy. And
there's an AD on the wrist pins because they break, and the rods will
break too. The only way to go 80 is with bootleg pistons and a few
other mods. There's a Cub in SC with Chevy pistons. It makes more
power than a C-85 Cub, or at least climbs out faster. You can't get a
Cub to cruise faster because it is so aerodynamically dirty.

Stay with an A-65-8. It is great reliable power and will last a long
time if you fly it regularly. Jugs will last a max of 500-700 hours.

On Apr 17, 3:13*am, "oilsardine" wrote:
hmmm....
thought to replace my Revmaster with this Conti, but now, mybe I better stay
with the VDub?

Now you have me confused. If you are thinking that you need to up the
hp of the Cont to match the performance of the Revmaster you've been
drinking someones Kool-aid....................by the pool full :-)

Seriously, more info would help. What is you goal? What kind of
plane? If your plane can handle the extra weight, required prop
length and the C 65 is a good buy you might be better off with the C
65. If your flying something like a KR originally designed around a
VW your probably going to be better off letting the C 65 rest. Is
your Reve giving you problems or less than expected performance?
There are other options to consider. Subaru n 'Vair pop to mind.
==============
Leon McAtee

schrieb im Newsbeitrag
...
..... Seriously, more info would help. What is you goal? What kind of
plane?

I have a Revmaster (normal aspirated) in an slightly :-) overweight Sonex.
The plane hasn't flown yet. Some extra HP could help. The Conti would fit
weight-wise, but seems also underpowered for this application. The Conti
turns slower than the Revmaster, but my prop diameter is limited by ground
clearance...

On Apr 17, 8:41*am, "oilsardine" wrote:
schrieb im ...
.... Seriously, more info would help. *What is you goal? *What kind of
plane?

I have a Revmaster (normal aspirated) in an slightly :-) overweight Sonex..
The plane hasn't flown yet. Some extra HP could help. The Conti would fit
weight-wise, but seems also underpowered for this application. The Conti
turns slower than the Revmaster, but my prop diameter is limited by ground
clearance...

Kinda spected this was where we was headed. Unfortunately I don't
know of a good solution to your problem. The prop diameter limitation
and intended cruise speed (common on lots of VW based designs) means
for all practical purposes you are stuck with a direct drive solution,
and in this power range the options are limited.

The Subaru won't gain much over the VW in direct drive configuration
and adds the complexity of water cooling.

Making some assumptions about your Sonex, a Rotax with a 3 blade prop
might be an improvement? But it too is water cooled.

Some seem to like the Jabiru as a VW substitute.

How much over weight? Would a diet be a better solution?

Too bad there isn't an inexpensive controllable pitch prop available
for this kind of application........................other than the
Ivo?

Editorial comment: 2 place VW powered planes are practical IF BUILT
LIGHT and the true limitations of a VW based engine are kept in mind.
Unfortunately it seems that builders of everything from Cygnets to Qs
and Vari EZs fixate on advertised numbers and we end up with
dissatisfied builders due to less than advertised performance. In
most cases it's not due to "embellished" factory numbers but the fact
that in this weight and Hp range there just isn't any more to give and
a hundred, even 50, pounds more makes a drastic cut in performance.
This is one of the oldest stories in home built aviation, and not
limited to VW designs. It's sad that it keeps getting repeated. If
expectations were more realistic, and thus met, maybe our sport/hobby
would have more active members?
==========================
Leon McAtee

schrieb im Newsbeitrag
...
....
Kinda spected this was where we was headed. Unfortunately I don't
know of a good solution to your problem. The prop diameter limitation
and intended cruise speed (common on lots of VW based designs) means
for all practical purposes you are stuck with a direct drive solution,
and in this power range the options are limited.

yes, and financial options are limited as well at this times...

The Subaru won't gain much over the VW in direct drive configuration
and adds the complexity of water cooling.

Subaru may be over the Sonex 200 lb firewall forward limit

Making some assumptions about your Sonex, a Rotax with a 3 blade prop
might be an improvement? But it too is water cooled.

financial limits...

Some seem to like the Jabiru as a VW substitute.

6-cyl. Jab is the optimal powerplant but $$$$$....

How much over weight? Would a diet be a better solution?

I said the SONEX is overweight, not me ;-))

Too bad there isn't an inexpensive controllable pitch prop available
for this kind of application........................other than the
Ivo?

Ivo and direct drive 4-cyl., not a good match...

Editorial comment: ....

very true