Engineering question

Steve B wrote:

100 pounds won't even come close to bending it.

According to my steel tables the piece you have should support 2,800
pounds without a problem.

--
Steve W.

wrote:


OK, that was way too easy for you. I need to ask this before I head
south.


I'm buying a boat that will have a big block V8 engine in it. I don't
know the weight of a big block engine so I'll guess 3000 lbs. The boat
beam is 8.5 ft.  If i ever need to pull the engine, I'll go to the
local lumber yard and build pillars for either side of the boat and
lay a steel beam accross. How big a beam do I need?

I'm looking at a less expensive version of this
http://tinyurl.com/43lzwr4

Karl

 

Karl Townsend wrote:

A big block V8 gas engine should be under 1,000#.

wrote:


Chevy's heaviest contemporary engine weighed 685 (427cid), Ford's 720
(460cid), Chrysler's 745 (331 hemi).


http://www.gomog.com/allmorgan/engineweights2.html
Interesting chart.

--
Happiness lies in the joy of achievement and the thrill of creative effort.
                                                  -- Franklin D. Roosevelt

Larry Jaques wrote:

If the boat engine is a diesel it will be heavier, but likely still
under 2,000#

wrote:


You guys are all forgetting about the tranny that comes out with the
engine. Marine engines blocks are far larger allowing for raw water
cooling. I think 3,000 is still a good guess.

Karl

Karl Townsend wrote:

If you aren't separating the tranny first, that certainly adds weight.
It certainly doesn't hurt anything but the wallet to have more safety
margin in the lift system.

wrote:


You tripped my trigger on how to make a portable hoist frame. I'll
start with two warehouse loadrack uprights and two warehouse load
beams. make the uprights into  A frames that bolt together. When
needed make up A frames and use the loadbeam pins to put the loadbeams
in place. it will all break down into a small stack for storage.

At least for me, just talking about something gets the creative juice
going.

Karl

wrote:


A marine gearbox is normally lighter then an automobile box a all
there is, is forward and reverse.
--
John B.

On Tue, 16 Aug 2011 11:44:23 -0500, Karl Townsend


Not usually. Marine engines are normally built with a standard engine
as a base with added "marine" accessories like the heat exchanger,
etc., and possible a heavy flywheel or crankshaft if designed for
commercial use.

--
John B.

Since no one actually answered Karl's question I'll play what-if.  For fun
using your 3000 lbs and a beam simply supported at the ends with a span of
10', I used a load of 9000 lbs concentrated at the center (using the x3
factor for a live load to take into account when it bounces up and down as
it comes off the mounts :-)).  With 4" square tubing 0.5" wall the max
deflection is 1" and the peak stress is 48 ksi which is getting right close
to (or over) a typical yield strength for structural steel, so if you use
square tubing it better be 5" and heavy wall, or bigger.  There are two
types of I beams, S and W, looking at S beams a 5x10 which is 5" tall and 10
lbs/ft (and the flanges are 3" wide) standing so it is 5" tall and 3" wide
is a tad weaker, and the lightest 6" beam, S 6x12 is more than enough
(assuming no additional safety factor and a yield strength of over 40 ksi),
deflection .51" and max stress 37 ksi.  In the W series the 5x16 is about as
strong as the S 6x12.  So any 6" I beam or a W 5x16 would just do it.  Make
sure you have the beam tall and narrow and clamp it so it can't twist and
all fall down :-).  I like the shareware program engineering power tools
available at www.pwr-tools.com for doing this stuff.  The free version is
fully useable and does basic beam stuff like this along with lots of other
useful stuff, and if you pay the $45 and get the full version you get lots
more.  Well worth it. (I'm not an engineer, this is worth what you paid for
it, yadda, yadda :-)).

-----
Regards,
Carl Ijames

"Karl Townsend"  wrote in message

wrote:


You guys are all forgetting about the tranny that comes out with the
engine. Marine engines blocks are far larger allowing for raw water
cooling. I think 3,000 is still a good guess.

Karl

On 8/16/2011 8:17 PM, Carl Ijames wrote:

Thanks for the tool link, Carl.

But I still think 3000 pound guess is a bit high for a 600 pound motor.

wrote:


 Definitely.
When he says "big block" I'm ASSuming he's talking a GM V8 Elephant -
396, 427, or 503 - or a Ford 460, or a big Mopar (413 etc) , all of
which see a fair amount of Marine use.

 Fully loaded for marine use, the ENGINE will be under $1000 in all
cases - the gearbox (straight or V Drive) will add a couple hundred.
I'd say 1500 would be pretty safe for an "all in" weight

120lbs (12Lbs x 10') of steel could be difficult to set atop the posts
safely without an engine hoist etc. The 8' rail for my temporary gantry
crane extension is bad enough to maneuver overhead at 80 Lbs. I balance it
on a second taller stepladder to allow one free hand to align it and insert
the bolts.
https://picasaweb.google.com/KB1DAL/Firewood#5287788504883032706

I have been considering a gantry with the beam hanging from a tripod on each
end. It won't be as mobile as one on wheels, but the posts will be in pure
compression, without bending loads, so they can be lighter. The beam can be
heavier since the tripods can lift the ends. The trolley would likely be
moved with block-and-tackle attached to the beam ends, minimizing lateral
tipping forces on the tripods. It would disassemble into channel and round
posts for compact storage and not have any welds to rust.

Has anyone ever seen or used such a rig?

jsw

[quote]
"Richard"  wrote in message

On 8/16/2011 8:17 PM, Carl Ijames wrote:

Thanks for the tool link, Carl.

But I still think 3000 pound guess is a bit high for a 600 pound motor.
[/quote]

I'm not disagreeing at all, but at least now Karl knows that if it really is
3000 lbs then a 6" I beam is the bare minimum, and if it really is 1000 lbs
he will have an extra factor of 3 safety margin.  The rest is up to him
(hey, us Carls have to stick together even if he does spell it funny :-)).

-----
Regards,
Carl Ijames

Karl Townsend wrote:

  The engine block used in marine engines is the exact same one used in
other applications.
If it's a big V-8 then it's either something like a 460 Ford or a 454 or
502 Chevy.
Mercruiser uses mostly GM products, Volvo/Penta uses Ford and GM if the
engine is a gasser, The only real difference between the street engines
and the marine engines are the camshafts and the exhaust manifolds. The
cams are usually ones ground to give a flatter torque curve at a lower
rpm than the street versions. The exhaust manifolds are cast so they can
be water cooled. The rest of the parts can be interchanged easily. BTDT
a lot.
Until you get up into the BIG diesels most of the boat engines used are
nothing more than heavy equipment engines.
Cat/GM/Perkins/Cummins/Waukesha/Mitsubishi all have been used as well as
some others. Nothing special about them.



--
Steve W.

Unless you're talking about a truly immense engine, you have too many zeros in
that figure.

I see the boat in your link has a 5.9 liter Cummins Diesel. My pickup truck
also has a 5.9-liter V-8 (tho not a Diesel) and the *entire truck* weighs
about 3800 pounds.

Karl Townsend wrote:

Well if it's a BB gasser the engine and drive will top out around 900
pounds.

Just grab 3  6X6 wood beams and brace them up. Will hold all of what you
have with no problem.

If you have the steel laying around then anything over a 6" I beam 9
pounds per foot in either S or W section would do the job with plenty of
safety factor.




--
Steve W.

I figured, but wanted to ask someone who would know.  I like to have a 3+
factor on my rigging.  This is sure going to make it easier to move that
welder all over to weld out all the little connection points.  I made a 6'
high stand on my little ATV trailer.  It was more stable than I thought it
would be, but still the hose is too short to reach everywhere.

Steve