Jacking up the 911
 

I was just wondering how much your engine is supposed to rise when you jack up the car under the sump plate?

I did mine today and it moved about 1/2" or so.

Is that normal or do I need to get some new motor mounts?

Don't know the answer to your question and I do know that many jack their car via the engine but I do not like the idea of raising my car on it's single most expensive component.

Yeah. I suppose it does seem a little precarious, but really it is just taking weight off the engine and pulling up the car on the motor and transmission mounts. Those mounts don't cost much.

Mine lifts more than a 1/2 inch.... I think you're fine with that type of travel, the whole engine/tranny dealy is moving as an assembly, and I would think there is enough extra in the wires, cables and hoses to deal with it. That said, some new motor mounts would probably reduce the movement, especially if you went with solid or semi-solid type mounts (I think Wevo makes these?).

1/2" seems about right.

I didn't notice any "play" when I jacked my engine up, but this summer, I dropped the engine and found that the motor mounts were bad as well as the rear engine bracket. I replaced them as well as the rear shocks and my car shifts so much better , it's unbelievable.

Actually, I don't think you should heve thst much movement up. Mine does move at all. As soon as I jack it goes up. I also replaced me tranny/motor mounts a few months ago. Its not a big deal, just means your motor gets to move around alot un power thus loosing a little torque...

Jerry Woods and Bruce Anderson say that is a great jack point.

Yes I know but I still do not feel ok about it while there are other points that seem to get the job done at less (percevied) risk.

I was going to use the engine as a jack point this weekend but the later models have the drain plug moved to the side of the engine so no flat sump to use. Should I just use a block of wood against the ribs on the bottom? i really want to change my motor mounts cause I believe they are affecting my shifting as well. Anyone done this with an '84 or beyond?

Don't use the engine.

Imagine flipping the engine upside down and using a hydraulic press on it at a force of 1500 lbs. This is what you're doing by lifting by the engine. Any harmful side effects? Who knows. I'd rather not risk it.

In another thread, someone mentioned a Pcar owners manual suggested not lifting by the engine.

They said "a great jacking point"?

Sherwood

I took a class with Jerry woods as the instructor, and he said either use the jack pads, or just use a block of wood or newspaper with a jack underneath the sump. Then he proceded to jack up the car with the engine as the jack point.

chris

The 101 Projects book also highly recommends this as a jacking point. If I want to change my motor mounts how should I suppot the engine to change them out? I suppose there would not be any "addtional" weight other than the engine itself if I'm just supporting the engine with a jack. Anybody else have a suggestion? I used the jack pad this weekend and it worked great for getting the car up on stands.

As you said, supporting the engine with a jack is not the same as lifting the rear end of the car with a jack.

I understand Wayne advocates using the engine too. Take my last post as a suggestion for the reason given. Do what you think is right.

Sherwood

I've used the engine as a jack point many times. If your replacing the mounts, put the weight of the motor on the jack, unbolt the the bar at the mounts and lower the motor an inch or two. Replace the mounts and raise the motor back up with the jack. I just did this. Took 20 Minutes.

I don't know if this helps, but I think about the stress put on any part of any car when lifting. For instance, a simultaneous lift at four points would be the least stressful.

I always try to spread the load over a larger area. So, If I want to lift the front, I use a 2x4 under the gas tank support right at the tow hook. If I lift one side, same thing witha 2x4 grooved for the pinch seam.

As far as the back goes, I look at it as Sherwood does. I think about the jack pad and how the car wants to roll to the front lip of the pad as it goes up. So, again, more wood. This time, I use a bigger piece cut here and there and long enough to spread weight from behind the sump to the tranny side plate.

This still leaves the motor mounts as the part that lifts the rest of the weight of the rear body less the weight of the motor. I can live with that. But, I think about it. It would seem that if you are aware of what you are doing, you wouldn't consciously misplace undue stress.

A lifting beam or cradle would be a nice aid. Trouble is, you'd have to lift the car to get the device under there.

Group buy on scissor lifts?

Count me in!

I'm with Sherwood, why would you use an engine notorious for leaking oil and that costs a small fortune to rebuild as a jack pad? It takes 2 min. to jack it up using the factory recommended spots and the manual specifically says NOT to jack under the engine. :confused:

I don't think 1500lbs is accurate. Say the engine/tranny combo weighs 600, so the rest of the car weighs about 1900. But you're not lifting the whole car, you're just lifting the back and much of the weight is still on the front wheels. The higher you go the more force is applied to the front wheels and off the jack, as well.

From an experimental side of things, so many 911 owners use this point and I have yet to here of any ill effects of it. However, knowing a bit about VW bugs and that they are notorious for crumpling right above the jack slot in the rocker (and the same jack pad is used for bugs and 911's, the slot is the same) especially when a bit rusty, I am extremely skeptical about jacking a unibody car (namely my 911) from a point like this. Were I to jack the car not from the engine, I would feel safest using the trailing arm.

"I don't think 1500lbs is accurate. Say the engine/tranny combo weighs 600, so the rest of the car weighs about 1900. But you're not lifting the whole car, you're just lifting the back and much of the weight is still on the front wheels. The higher you go the more force is applied to the front wheels and off the jack, as well. "

I estimated my calcs based on the following:

Weight distribution of a 911 is typically 40-60 (frt/rear)

I estimated this 911 @ approx. 2500 lbs.

60% of 2500 lbs = 1500 lbs.

Are you suggesting the weight (1500 lbs.) automatically shifts toward the front when the jack touches the engine or after it's lifted?

At what height does the weight shift toward the front?

Respectfully request you recheck your physics.

Sherwood