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[Healeys] I Dropped the Engine

To: Healeys <healeys@autox.team.net>
Subject: [Healeys] I Dropped the Engine
From: Joe and Lenore Armour <sebring@illawarra.hotkey.net.au>
Date: Tue, 11 Aug 2009 23:31:24 +1000
A serious point to consider as to whether the factory recommended lift 
points are safe depends on how they are loaded ie. in what direction 
does the force diagram and tension in the connections between the hook 
of the hoist and the two brackets fitted to the rocker studs.  With the 
loads from the chains or rope/webbing slings vertical there is plenty of 
capacity with the studs in tension. When the ropes/slings are shortened 
in length, the forces on the brackets and studs becomes a side load ( 
draw a diagram of the hook point: rope lengths: distance between the two 
rocker studs. The shorter the rope/slings the greater the side and 
therefore the BENDING LOAD on the bracket/studs.

Chains used as two fixed lengths between studs and hook are extremely 
bad when the engine/transmission are tilted to clear the body. The 
effect of this is to transfer the majority of the load/force onto the 
back chain as the front chain lifts towards the hook.  Fixed 'leg' 
ropes/slings are the same unless they are free to slide through the 
'bite' of the hook allowing the weight/load to be equalised between both 
'legs' of the rope/sling/chains and therefore loading each stud with 50% 
of the weight.

Longer 'legs' of rope/sling/chains are much better but the  ability of 
the engine crane to raise sufficiently becomes an issue. The garage 
(shop) ceiling height and dont forget that the car will raise up on the 
springs as the crane takes the weight of the bloody great boat anchor ( 
that I love).
Remember granddad's old under the tree lifting mechanism, much higher 
than todays portable units

Look up any riggers handbook or talk to a mathematician about the 
'force'  diagram which can create serious side - bending - loads into 
the studs.

A rocker stud or any grade 8 bolt of this diameter will lift tonnes in a 
direct tension situation. Brackets must be tightened down onto rocker 
pedestal
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