The Murphy Builders Site

I am interested in using the Northwest-Aero Chevy LS-1 V8 conversion on my
Super Rebel. Does anyone have information about the positioning of the
center of thrust (i.e., prop hub location, how the prop shaft is angled,
whatever). I have heard things like 19 inches up from the bottom of the
firewall and angled such that the center of thrust passes through some place
on the tail. Stuff like that. I have also heard that it is easier to begin
by suspending the engine from the ceiling over the firewall (or a mock up of
the firewall). Any other tips or advice on how to fabricate an engine mount
from scratch?

Mike Kimball

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The complete LS-1 engine installation, including all accessories, is 490
lbs. It's rated at 350HP@5500rpm for takeoff and 300HP@4250rpm continuous.
That compares favorably to the M14P which allows 360HP for takeoff, but
lists cruise HP at only 200HP. Of course, the M14P only has to turn less
than 3000rpm for that, which is a huge advantage. The other engine of
interest is the Suburu from Crossflow in Ontario. They have three suitable
engine models ranging from 250HP to 320HP. Two of the three models are
turbocharged, which should be an advantage for high altitude operation.
Interestingly, the 300HP turbocharged model lists a fuel burn of 10.2gph and
the 320HP high output engine lists 9.1gph. Also, the high output model
apparently gets the extra 20HP from rpm. It's rated 320HP occurs at 6050rpm
versus the 300HP model at 5600rpm. The huge advantage of the Crossflow
engine is that they provide a firewall forward package, including engine
mount, radiators, and other stuff that would be a challenge to engineer
myself. But the scary thing about auto engine conversions for me is high
continuous rpm. At least the LS-1 has two extra cylinders and turns quite a
bit slower than the Suburu. I've had more than one experience of cylinders
failing for one reason or another on auto V8s and the engine keeps running
anyway.

I would dearly love to use the M14P, but Murphy is adamant about doing the
gross weight upgrade if the M14P is to be used. I have a lot of my project
completed already so that would mean tearing into parts that I don't want to
tear into, such as the sealed and tested wing tank. So off I go, exploring
other engine options. One thing for sure, I can't afford a $40,000 (or
more) Lycoming and I don't want to keep paying ridiculous prices for parts
to maintain it.

Mike

-----Original Message-----
From: Bob Patterson [mailto:bob.patterson@canrem.com]
Sent: Wednesday, January 10, 2001 3:32 PM
To: Murphy Rebel Builders List
Subject: Re: Engine Mount Fabrication



Hi Mike !

I'm sure the Murphy Tech. Dept. can supply all the needed
measurements - thrust line position, offset, etc. .... They have
done this for the Rebel for several builders.

How heavy is that complete installation, compared to an O-540 ??
How many HP. ?? Perhaps NWA can supply some info on the mounts
others are using ...

.....bobp

---------------------------------orig.---------------------------------
At 11:50 AM 1/10/01 -0900, you wrote:

I am interested in using the Northwest-Aero Chevy LS-1 V8 conversion on my
Super Rebel. Does anyone have information about the positioning of the
center of thrust (i.e., prop hub location, how the prop shaft is angled,
whatever). I have heard things like 19 inches up from the bottom of the
firewall and angled such that the center of thrust passes through some

place

on the tail. Stuff like that. I have also heard that it is easier to

begin

by suspending the engine from the ceiling over the firewall (or a mock up

of

the firewall). Any other tips or advice on how to fabricate an engine

mount

from scratch?

Mike Kimball

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---------*

Contributors' page at:
http://www.dcsol.com/murphy-rebel/contributors.htm
Visit the book store at:
http://www.dcsol.com/murphy-rebel/book_store.htm
Archives located at:
http://www.dcsol.com/murphy-rebel/archives.htm
*--------------------------------------------------------------------------

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Contributors' page at:
http://www.dcsol.com/murphy-rebel/contributors.htm
Visit the book store at:
http://www.dcsol.com/murphy-rebel/book_store.htm
Archives located at:
http://www.dcsol.com/murphy-rebel/archives.htm
*---------------------------------------------------------------------------
--------*

*--------------------------------------------------------------------------

Contributors' page at:
http://www.dcsol.com/murphy-rebel/contributors.htm
Visit the book store at:
http://www.dcsol.com/murphy-rebel/book_store.htm
Archives located at:
http://www.dcsol.com/murphy-rebel/archives.htm
*--------------------------------------------------------------------------