I assume you must use the jack points under the car to lift it but where to you place the jack stands? Is there a generally accepted location?

 

I bring the jack in from the center of the back bumper and do an engine lift. I then place jack stands (low profile) at the rear jack points.

 

Good info here: http://www.renntech.org/forums/index...on-jackstands/ But for the engine lift the position of the jack in the center of the crankcase is a bit different... Also here: https://www.6speedonline.com/forums/...le-stands.html

 

Do not use the engine case to lift the back of the car. Although many people do this, you are asking for trouble. The cross member in front of the engine case attaches to a suspension carrier subframe. You can either jack the car from the rear jack points (with a long low profile jack) and slip jack stands under the suspension carrier at the crossmember or lift at the carrier points and place jack stands at the jacking points. Remember the car is very stiff and lifting from one side in the rear could unseat a jack stand in the front. Best to use two jack and lift the car evenly. An over abundance of caution can mitigate unintended consequences.

 

If you use the actual jack point to lift, you can place the stands here:

 

Can you elaborate?

This is from GMG's shop. I'm assuming that they would practice a safe technique.

 

What I found works well is to have two jacks. Put one under the rear jack pad and lift to obtain clearance to use the second jack under the rear cross member.
More info here https://www.6speedonline.com/forums/...bolt-mods.html

 

[QUOTE=bbywu;3418179]Can you elaborate?


When you are jacking the rear using the engine case you are transferring the whole load of the car by the two rear engine mounts which are not designed for these type of negative loads. People do it, but I wouldn't. I use two low profile jacks with stop pins and jack using the factory jack points. Then I install the pins locking the jacks in position. I leave the jacks in place and in addition I place two jack stands under the rear suspension carrier (as pictured in an earlier post here) as back up. I think a lot of shops use the engine case as it is the quickest method and for them time is money. I seriously doubt a factory Porsche shop uses the engine case to jack the car.

 

I was never able to find a low profile jack with built in stands low enough to slide under my GT3, so I am forced to use either the jack points or the engine crankcase.

Although the engine mounts are designed to support lateral displacement, I assumed that it would support downward force of the chassis with upward lift of the engine. On many tracks, the car is designed to take significant lateral and vertical forces. Perhaps I should reconsider.

 

My Rturbo is low also and I can't just slide a jack underneath it unless it's super low. I normally place a 2x6 piece of wood behind each rear wheel and drive up onto it. That gives me enough clearance to stick a jack under there no problem. Takes 30 seconds.... If you think about it, the engine mounts are rubber or in some cases silicone filled and I seriously doubt they were designed for a 2000+lb. vertical load acting in an UPWARD direction. The mounts are designed to absorb mainly lateral loads and a fairly small vertical load (weight of the engine) in downward direction.

 

Yah I know many of the shops I've been to pull this stunt. It's dumb, lazy or both. I specifically write on the work order, DO NOT LIFT CAR BY ENGINE CASE. If they ignore me and something bad happens, it's going to cost them a new motor. The engine case was never designed to carry the load of the rear of the vehicle. Look how thin the engine tail piece is compared to the jacking plates and suspension sub chassis. If you're going to bend or break something, the last thing you want it to be is the engine case. The picture in the post a few above this is the correct and best location without using a floor lift. The only situation that you have to place a jack under the engine case tail piece is if you're changing out the motor mounts. In this case use a piece of 2x4 cut to the length of the tail piece and place it between the jack cup and engine case to help distribute the load in conjunction with the jack stands at the suspension carrier.

 

I just did this today exactly as pictured and would recommend it for several reasons:

-Eliminates the debate/concern about lifting from below the engine (therefore no engine mount failure issues).
-Lifts up the car at the only jack point locations indicated on the vehicle.
-Does not require multiple jacks.
-Works like a charm, was easy and straight forward to do.

 

In 40 years going back to my time at the factory the jack was always placed under the engine case close to the flywheel, it did not touch the transmission bellhousing. I have never seen or heard of a failure of an engine case as a result of this. Maybe you have a different experience