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let's talk about engine stands

goldhunter_2

goldhunter_2

Well-known member
I mounted my cage today and dropped off my case to get bored so I am starting to think about engine stands .

question #1
if you could build out of either aluminum or steal square tube with would be better and why?

question #2
witch stand type is better and why , the three point type or the full square frame to mount four point attachment?
 
I was planing to have a inch or so adjustment but with that gear box on there it should be pretty well a fixed point if I mount it level.


How much adjustment where you thinking?
 
Never go with a three point on a car motor! Everybody loves those three point stands and they all say well the motor box's it all in yes it does however if a motor mount ever fails your engine stand will fail! I had a three point come apart on a car motor boat and I still ain't figured out how nobody got seriously hurt! A/C motor guy's love them because their so light to me the 6 or 7 pounds it saves ain't worth risking my life. Maybe on a 4 banger their safe but not a hooped up 6cyl or supercharged motor!
 
I'm glad to see this one come up again ....
I've seen engine stands that scare the crap out of me. Like Thunder said, the only difference between a stand that is up to the job and one that might kill you is 10 pounds at most.

When I had my boat rerigged this Winter that was my only request ..... no matter how rough the water gets, no matter what else, that old small block and prop have to stay right back there where they're supposed to be.
 
Rich, those are some of the ones I'm talkin about. I've see BA 572's, with a gearbox, sitting on 1/2 tubing ...... :shock: .
It might work today, it might work next week, but it won't work forever.
 
olf art,
the only things that last forever are death and taxes :lol:




I am not sure I understand what is meant by the stands will fail or collapse since both types are cross braced, but I do see the consensus is to build a square frame stand with square platform to set the engine on o I guess I plan on something like that again
 
goldhunter, I used to be the Wing Safety Officer when I flew jets with the Air National Guard. I learned a lot about the failure of aluminum. Aluminum does not hold up to the stresses you will get on an airboat. By the time you engineer a suitable stand it will weigh almost as much as a well built steel stand.

I think Whitebear posted a nice stand design when Red Dwarf was building his boat. A 3 point stand is all right for 4 cylinder aircraft engines but not the 6 cylinder models and definitely not car engines.

I personally like the looks of the square tubing. Dakota Airboats has great prices for his stands and the quality looks outstanding. I wouldn't even try to build my own when I could buy a professionally made one for the prices he charges.
 
Im in total agreement with square tubing engine stands.

There is something I learned while working in seismic with a 35-50 boat fleet and that is that there should be NO connection between the fron and rear sections of the stand. Thats the engine and reduction drives job. Any other connection almost insures long term cracking somewhere on the legs. Every single one we had with a bar run from the front mounts to the rear mounts had cracked down close to the stringer. Every one I removed that bar from never cracked again.

Engine_Stand.JPG


Scotty
 
Des,
I'll take your word on the aluminum though I have never tore aluminum and have steel was just thinking , no rust :D this boat will be that 6cy GPU case aircraft conversion with gear box


Whitebear,
Humm..... ok now you have the wheels in my head turning you can probably see the smoke form there :D
my old engine stand is "X" braced form side to side and front to back then has a square frame on top witch the engine mounts connect to , but your saying no front to back connection other then the engine :?: that would save allot of wight but wouldn't that be to week to handle this kinda of torque :?:

Oh ya I can't just use the old stand it isn't wide enough at the base
 
I think good triangulation is the key.

Build the stand so that the angles support the loads, not the welds and you should have no problems!

I am running a 300 hp 0540 on a 3 point stand made out of 1" x 1" 10 ga sq tube (metal) The front and rear are attached to each other, as they mount on 4 1"x 3" pads.
This particular stand is 20 years old and on its third motor and has thousands of hours of extreme running on it.

All of the boats we build and use have the same general design stands and none have ever failed. They have been through crashes, roll overs and lots of prop failures.

I am not disputing any ones opinions just stating the facts I base my own opinion on!

Grant
 
Amen to that Grant, triangulation, triangulation! The design is just as if not more important then the material and you all can have them nice shiny aluminum stands! Aluminum crystallizes when it's bent beyond a certain radius and I have seen a ton of those mega dollar aluminum stands with all those spider cracks from being bent to much!
 
We have considered doing some Aluminum Cages but we will not be building any Aluminum Engine Stands. Not worth the possible risk of problems that could result. I gotta say, I love the look but safety is more important.
 
goldhunter_2":y88y1wxt said:
Whitebear,
Humm..... ok now you have the wheels in my head turning you can probably see the smoke form there :D
my old engine stand is "X" braced form side to side and front to back then has a square frame on top witch the engine mounts connect to , but your saying no front to back connection other then the engine :?: that would save allot of wight but wouldn't that be to week to handle this kinda of torque :?:
Click to expand...

That bar is put there when the stand is built with a jig or empty block to ensure alignment after its removed from the jig. That implies warping when it is built or there would be no mis-allignment. You can't have two unequal paths for stress, EVENTUALLY one will ALWAYS break. On my graphic above it is not noted and should be that the front to back apparent X brace is not connected. The front legs are wider thant he rear legs and the diagonal braces are NOT connected. It IS X braced side to side.

Grant and Dave have it right, its the design not the material.

Anectodally, we built an engine stand out of 3/4" conduit for a Buick 350 DD boat years ago just to help a boy out and save him a few bucks. Once he came flying up the ramp at the local airboat club and launched his boat at least 2-3 feet into the air and slammed down in the parking lot. There was not a crack, bend or break anywhere in his stand. We did a VERY CLOSE inspection. Oh yes and that stand was brazed as well. Not a weld on it anywhere. I don't recommend doing this but it is to illustrate that the strength comes from the design not the material.

Scotty
 
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