Aluminum Oil Sump Plate Safe Jack Point?

[jaustinmd]

My '82 911SC has the oil sump plate without a drain plug. I understand this is a preferred point to place a jack to jack up the rear end of the car. If I change the oil sump plate to an aluminum one with a drain plug, will it still be safe/strong enough to bear the weight when jacking up the car?
I "think" some of the plates are cast aluminum and some are machined billet 6061T6 aluminum. I'd probably go with the machined billet but are the cast ones strong enough? Or, would it be better to find a used steel plate with a drain plug?
Thanks,
John

[911s55]

I have one of the Mainely covers on mine for about 8 years and no issues. I also use a heavy leather glove folded over as a pad between the jack and plate.

[RDM]

Better still to use the case seam and cushion your jack with rubber. Nice thick cast aluminum won't be going anywhere.

On the other hand, if you bend the plate it's easy to replace.

[will hung]

I always jack mine from the sump plate, mine is a '79 SC complete with drain plug, but I don't jack directly on the plate. I always place a greater Pittsburgh area phone book between the jack and the sump plate. When the new one arrives, I throw the old one away and use my spankin new pad.

[911pcars]

While preventing metal-to-metal contact, a glove, phonebook or hockey puck doesn't change 1500 lbs. of force on the sump plate or engine case. YMMV.

Sherwood

[Bill Douglas]

I never have and never would jack my SC up by having the jack under the sump. I've seen pics of the factory doing it, I just don't like the idea of the poor little engine mounts lifting up the weight of the back of the car. I've bitten the bullet and bought a scissor lift.

[afterburn 549]

Not a good idea. if you have ever had one apart -its just a thin aluminum case.

[HarryD]

I know lots of folks lift the rear via the engine but you need to ask your self: Why are you lifting your car with it's most expensive mechanical component?

I lift my car using the jack points on the chassis.

As posted before:

Originally Posted by HarryD

Josh:

Lots of discussion, lots of opinions.

Personally, I have heartburn using the single most expensive to repair component of my car to lift my car.

A search using keywords like lift points, jacking, jack stands will provide overwheming feedback. You can do a search with any of those terms and turn up hundreds of threads.

This thread (Jack Help! (Urgent)) has one of the most definitive postings (thanks Bill Verburg):

Originally Posted by Bill Verburg

X's for lifting O's(and X's for stands), there are others, the Os are almost impossible to get a jack on

[Craig_D]

Why not just use the motor? I've jacked mine up many times using the motor, but never on the sump plate. It makes no sense to choose the one thing that is of lighter material and bolted to the stout motor itself, instead of the motor.

[afterburn 549]

Just what if ?

[Flieger]

How else are you going to get both wheels off the ground at once? Why not lift the car from the second heaviest component?

[HarryD]

I lift one side with the factory jack point. Place my jack stands as needed. Then lift the other side.

[afterburn 549]

Everyone that has a aircooled P car ought to get a little scissor lift of sorts.
Not very expensive, and it allows you to roll around under the car safely in a moments notice.
They go high enough to drop and pull the engine. (about 3.5 to 4 feet is plenty.
simple

[Flieger]

Originally Posted by HarryD

I lift one side with the factory jack point. Place my jack stands as needed. Then lift the other side.

To me that seems less stable than lifting once from the middle. And while I jack from there when only lifting one side I have actually heard people say not to lift from the factory points because it puts too much stress in that corner with the weight of the engine hanging off the back. But maybe that is just for Targas.

Anyway, my car survived lifting it from both the engine (twice) and factory jack point.

[Flieger]

Originally Posted by afterburn 549

Everyone that has a aircooled P car ought to get a little scissor lift of sorts.
Not very expensive, and it allows you to roll around under the car safely in a moments notice.
They go high enough to drop and pull the engine. (about 3.5 to 4 feet is plenty.
simple

Cool, you got one to loan me? Is it low enough to clear my front bumper?

[Trackrash]

When I want both rear tires off the ground, I place the jack under the rear engine mount. Then again my motor is magnesium.

[Flieger]

Originally Posted by Trackrash

When I want both rear tires off the ground, I place the jack under the rear engine mount. Then again my motor is magnesium.

Mine's mag too. 1974 7R case.

[targa80]

I use a 2-1/2 ton jack just past the sump on the engine casing and forward of the tranny. I have used this method to remove/install the power plant 6 times successfully. it is a matter of getting the right balance point.

[afterburn 549]

Originally Posted by Flieger

Cool, you got one to loan me? Is it low enough to clear my front bumper?

Yes you can drive up on them with a lowered car to Ero Ht EZ . Mine is a tad lower.
Get the air over Hyd kind they use in a tire shop. It lets all 4 wheels hang.
You should be able to get a used one at reasonable rate . I paid 400.00 for mine

[KTL]

I agree that jacking on the sump plate is a bad idea. Just so there's no confusion, i'm talking about the 1983 and older engines with the removable plate. The 84-up engines have no sump opening, only a drain plug casting, and are OK to jack on even though I still don't like the idea of jacking on the aluminum engine case.

IMO your best bet is to jack it where Gordon (Trackrash) suggests. The challenge is accessibility with the jack head. A stock car with the big muffler, heater tubing and oil scavenge line makes it tough to get clean contact with the engine console. Nonetheless, when you put the jack on the steel engine console you're transferring the lifting force to the engine mount console & crossbar that is connected to the chassis/engine mounts. Lifting from there, the engine is just along for the ride and not necessarily being "stressed" to lift the car.

All that said, people have been jacking on the engine forever. So its proven to be OK. I just don't like the idea of putting the load on the very expensive engine.

One thing worth noting about that nice diagram Harry posted is that I would be very careful in the X'd areas that I point to below. Reason I say these are risky is because you have to make sure you get the stands in the right place. The right place is as far to the rear of the floorpan as possible, where the seam/pinch weld is. If you miss and put them just a bit too far forward, you'll put a HUGE dent in the floorpan.

I've seen a bunch of 911s over the years that have been dented there. Either there's a big mushroom in the floor/carpet or you can see where somebody hammered the pan back down to make it sorta flat again. So don't booger up your floorpan by putting your jack or stands there. Put the stands on the torsion bar housing (the "O" locations just below the risky X) or on the outboard bushing + spring plate tube area where it sticks out of the chassis in the wheel well (green circles)