| Traveller |
04-21-2012 02:37 PM |
Quote:
Originally Posted by EMBPilot
(Post 6702221)
definitely agree Traveller, good points...
and the poster above even mentioned the motor mounts as the stress points. things to ponder.
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Our engine hangs from those motor mounts, I believe. So they are basically holding up a part of what is a 550 pound motor (and a part of it being held by the transmission mount). Its another thing to use the motor and its mounts to hold up roughly 2/3 of our 3000+ pound cars (65% weight bias). Whether that will do any damage to the frame rails that the mounts attach to, I highly doubt it. Whether it might do any damage to the engine mounts...maybe.
Some might point out the location of the engine mount at the rear of the engine. Once again, that was designed to hold up an engine...not the other way around...to hold up a car.
What Porsche may be concerned with is the point contact area against the engine case and with a surface that uneven, how does one distribute the load?. And from what I can tell, many if not all owners using the engine to jack up their car are using the joint at the case halves. That may be thick, but the adjacent case is thin in comparison.
Once again, owners can do as they please and they may never have a problem that they will attribute to their jacking technique.
Someone kept stressing one of the training aircraft I used to instruct on. Every time I would come out of an up-to-five-turn spin and pull out with a couple of Gs, I'd hear a thud coming from the back. I brought it up a few times to the AME who joked about getting some thud remover from the local auto supply. At one of the upcoming inspections, they found a crack in the horizontal stabilizer spar. How nice...no stab...it pitches nose down. Bye-bye! Thats what happens when things are overstressed slowly but surely in time.
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