991.2 Rear Center Jack Point
07-29-2019, 02:58 PM
#16
Burning Brakes
I certainly gave that idea some thought. The oil pan being plastic is probably not too expensive if things didn't work out. But if you spread the bearing stress over a large enough area it should work.
Let's assume a force of 3,100lbs X 60% = 1,860lbf. So, if the 1"X6"X12" has a surface area of ~63 in^2 the resultant bearing stress is: 1,860lbf / 63in^2 = 30psi. Plastic should be able to support that kind of stress.
But what about the motor mounts?
Jason
Let's assume a force of 3,100lbs X 60% = 1,860lbf. So, if the 1"X6"X12" has a surface area of ~63 in^2 the resultant bearing stress is: 1,860lbf / 63in^2 = 30psi. Plastic should be able to support that kind of stress.
But what about the motor mounts?
Jason
1- You are assuming an evenly distributed pressure, the car's weight is not perfectly balanced between the two sides and even front and rear. You cannot consider the 1"X6"X12" to act as a monolithic member since it is going to be subject to different loads on each square inch.
2- The floor jack will give you a single point. Most of the pressure will be right at that point.
3- The car will not be raised vertically as the front will remain on the ground. You are dealing with angled loads.
4- The oil pan is not designed to support loads.
Not trying to prove a point... I just don't want anyone to break their cars.
Stay safe mate.
07-29-2019, 05:30 PM
#17
RL Community Team
Rennlist Member
Rennlist Member
Your math has flaws...
1- You are assuming an evenly distributed pressure, the car's weight is not perfectly balanced between the two sides and even front and rear. You cannot consider the 1"X6"X12" to act as a monolithic member since it is going to be subject to different loads on each square inch.
2- The floor jack will give you a single point. Most of the pressure will be right at that point.
3- The car will not be raised vertically as the front will remain on the ground. You are dealing with angled loads.
4- The oil pan is not designed to support loads.
Not trying to prove a point... I just don't want anyone to break their cars.
Stay safe mate.
1- You are assuming an evenly distributed pressure, the car's weight is not perfectly balanced between the two sides and even front and rear. You cannot consider the 1"X6"X12" to act as a monolithic member since it is going to be subject to different loads on each square inch.
2- The floor jack will give you a single point. Most of the pressure will be right at that point.
3- The car will not be raised vertically as the front will remain on the ground. You are dealing with angled loads.
4- The oil pan is not designed to support loads.
Not trying to prove a point... I just don't want anyone to break their cars.
Stay safe mate.
Get jack point stands or quick jack lift.
07-29-2019, 08:29 PM
#18
What I do is jack from the rear jack point high enough to get a stand under the front jack point and a stand under the rear crossmember near the reinforced area where the suspension arm attaches to it. Do the same on the other side and you're done.
07-31-2019, 12:53 PM
#19
Burning Brakes
Right, that works too! My only preference is to get jack stands under the two rear jack points at the "same time" and not perch the car one corner at a time.... But I've done it both ways numerous times without issue.
08-06-2019, 09:28 AM
#20
Racer
Thread Starter
Your math has flaws...
1- You are assuming an evenly distributed pressure, the car's weight is not perfectly balanced between the two sides and even front and rear. You cannot consider the 1"X6"X12" to act as a monolithic member since it is going to be subject to different loads on each square inch.
2- The floor jack will give you a single point. Most of the pressure will be right at that point.
3- The car will not be raised vertically as the front will remain on the ground. You are dealing with angled loads.
4- The oil pan is not designed to support loads.
Not trying to prove a point... I just don't want anyone to break their cars.
Stay safe mate.
1- You are assuming an evenly distributed pressure, the car's weight is not perfectly balanced between the two sides and even front and rear. You cannot consider the 1"X6"X12" to act as a monolithic member since it is going to be subject to different loads on each square inch.
2- The floor jack will give you a single point. Most of the pressure will be right at that point.
3- The car will not be raised vertically as the front will remain on the ground. You are dealing with angled loads.
4- The oil pan is not designed to support loads.
Not trying to prove a point... I just don't want anyone to break their cars.
Stay safe mate.