Jack Stand Placement
04-29-2002, 04:16 PM
#1
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Jack Stand Placement
Can someone tell me the best locations to place jack stands on my 1991 C2 once I have the car lifted using my floor jack placed under the front or rear lift points? Thanks! 
04-29-2002, 10:34 PM
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That is a great question...I've been wondering the same thing...Getting the car up on jack stands using only the 4 jacking points is a tough feat without a 5th jacking point...When visiting P-Car.com (a very nice 993 site) there is a DIY guide that recommends jacking the rear under the motor...this seems like a lot of strain on the motor mounts to me and Ive been hesitant to try it on my 964...I do beleive that the 993 mounts are the same as the 964 mounts...So far I've been able to do everything I've needed to do by jacking up one side/end at the time and/or using ramps...but would really like to get the car up on all 4s for some future work...
So lets here it guys...Is it safe to lift a 964 under the motor to raise both rear wheels??
So lets here it guys...Is it safe to lift a 964 under the motor to raise both rear wheels??
04-30-2002, 12:09 AM
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I have taken a block of wood and cut a kerf in it (to allow for the case half seam), and used it in rush emergency situations. It is not a practice that I'd recommend for the inexperienced. The risk are to high. If the car rolls forward or the jack settles on hot asphalt, a jack that tips can poke a hole in your case.
04-30-2002, 01:41 AM
#4
Race Car
I've got to say, I've been using the "jack underneath the motor" trick for years, and two 911s, an SC and my current 964.
As it is lowered, I drive it up onto a set of 2"x8"x 2' pieces that I've cut, so the car is 1.5" higher. I remove the saddle from my jack and place a piece of 2x4 on it and roll it underneath the engine to jack up the rear of the vehicle. The motor mounts are plenty strong for this procedure and you can then place your jackstands underneath your trailing arms.
Just be careful as you lower the car because most floorjacks tend to "arc" the car backwards when jacked up to the fullest extension of the jack. So when you lower it, the car will go a bit forward...after a few times, you will pretty much be able to "predict" where the car will settle on the jackstands - so pay attention!
I place my jackstands so they wind up holding up the car via the trailing arms, just in front of the hole in the bottom of the trailing arms, where the arm "forks" off for the wheel carrier and the forward suspension attachment point.
Somebody once told me that the holes in the bottom of the trailing arms are for some neat little hooks you can acquire to facilitate strapping down the vehicle when towing on a trailer. I haven't seen any of these...but would love to as for now I place straps through my rear wheels, with towels wrapped around them.
Anyone know of such a thing?
As for the front, I use a floor jack on either side of the vehicle (yes, I take two floorjacks with me to the track). To date, I haven't figured out a better way to jack up the front...so that'll have to do for now.
As it is lowered, I drive it up onto a set of 2"x8"x 2' pieces that I've cut, so the car is 1.5" higher. I remove the saddle from my jack and place a piece of 2x4 on it and roll it underneath the engine to jack up the rear of the vehicle. The motor mounts are plenty strong for this procedure and you can then place your jackstands underneath your trailing arms.
Just be careful as you lower the car because most floorjacks tend to "arc" the car backwards when jacked up to the fullest extension of the jack. So when you lower it, the car will go a bit forward...after a few times, you will pretty much be able to "predict" where the car will settle on the jackstands - so pay attention!
I place my jackstands so they wind up holding up the car via the trailing arms, just in front of the hole in the bottom of the trailing arms, where the arm "forks" off for the wheel carrier and the forward suspension attachment point.
Somebody once told me that the holes in the bottom of the trailing arms are for some neat little hooks you can acquire to facilitate strapping down the vehicle when towing on a trailer. I haven't seen any of these...but would love to as for now I place straps through my rear wheels, with towels wrapped around them.
Anyone know of such a thing?
As for the front, I use a floor jack on either side of the vehicle (yes, I take two floorjacks with me to the track). To date, I haven't figured out a better way to jack up the front...so that'll have to do for now.
04-30-2002, 07:23 AM
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[quote]Originally posted by Jeff Curtis:
<strong>Somebody once told me that the holes in the bottom of the trailing arms are for some neat little hooks you can acquire to facilitate strapping down the vehicle when towing on a trailer. I haven't seen any of these...but would love to as for now I place straps through my rear wheels, with towels wrapped around them.
Anyone know of such a thing?</strong><hr></blockquote>
Jeff - Once on Ebay someone was selling a set of original Porsche factory 911 tie-downs, used when transporting 911's on the tractor-trailers. This is probably what you are looking for. I wish I had gotten those!
<strong>Somebody once told me that the holes in the bottom of the trailing arms are for some neat little hooks you can acquire to facilitate strapping down the vehicle when towing on a trailer. I haven't seen any of these...but would love to as for now I place straps through my rear wheels, with towels wrapped around them.
Anyone know of such a thing?</strong><hr></blockquote>
Jeff - Once on Ebay someone was selling a set of original Porsche factory 911 tie-downs, used when transporting 911's on the tractor-trailers. This is probably what you are looking for. I wish I had gotten those!
04-30-2002, 09:18 AM
#7
[quote]Originally posted by Jeff Curtis:
<strong>I remove the saddle from my jack and place a piece of 2x4 on it and roll it underneath the engine to jack up the rear of the vehicle.
I place my jackstands so they wind up holding up the car via the trailing arms</strong><hr></blockquote>
Exactly where under the engine is the best contact point for the 2 x 4? Should the 2 x 4 be notched or fitted to mate with a certain location on the engine? I have this horrible vision of the 2 x 4 exerting TOO much force in the WRONG location. Yikes!
Any reason the trailing arms are a better point for the jack stands than the "official" lifting locations on the car?
<strong>I remove the saddle from my jack and place a piece of 2x4 on it and roll it underneath the engine to jack up the rear of the vehicle.
I place my jackstands so they wind up holding up the car via the trailing arms</strong><hr></blockquote>
Exactly where under the engine is the best contact point for the 2 x 4? Should the 2 x 4 be notched or fitted to mate with a certain location on the engine? I have this horrible vision of the 2 x 4 exerting TOO much force in the WRONG location. Yikes!
Any reason the trailing arms are a better point for the jack stands than the "official" lifting locations on the car?
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04-30-2002, 10:37 AM
#8
Instructor
Thread Starter
Thanks for all the responses! This site is such a great resource. I am still reluctant to use the engine as a lifting point due to the fact that Porsche specifically states not to in the manual. I have to believe they had a good reason.
04-30-2002, 10:51 PM
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Anewbill,
Remember that our cars came from the factory with the plastic engine under cover for sound deadening and aero improvements...Most owners have removed theirs permanently to allow the engine more air for cooling...Porsche probably did not recommend this because jacking the car under the engine with the plastic cover in place would have probably mangled the plastic...Also, trying top properly raise the car under the engine with that little aluminum scissor jack on the side of the road to change a flat would be asking for it...But in your shop, with a good quality floor jack and the proper attention and your in business...Just my theory...There are enough advocates on the 964/993 boards to ease my mind enough to give it a try next time I need to raise the car.
Good luck.
Remember that our cars came from the factory with the plastic engine under cover for sound deadening and aero improvements...Most owners have removed theirs permanently to allow the engine more air for cooling...Porsche probably did not recommend this because jacking the car under the engine with the plastic cover in place would have probably mangled the plastic...Also, trying top properly raise the car under the engine with that little aluminum scissor jack on the side of the road to change a flat would be asking for it...But in your shop, with a good quality floor jack and the proper attention and your in business...Just my theory...There are enough advocates on the 964/993 boards to ease my mind enough to give it a try next time I need to raise the car.
Good luck.
05-01-2002, 12:35 AM
#10
Race Car
As far as nothing the piece of 2 x 4, I don't find that necessary, as it would just weaken the piece and would really encourage it to split. I only use a specific piece of 2 x 4 a few times to lift the car via the engine, then I retire it.
Make sure that the 2 x 4 piece's grain runs from left to right and not fore and aft as the seam of the engine case and the weight involved will split it in two!
I wouldn't worry too much about causing damage to the engine case, it's pretty tough, after all it encapsulates a crank and rods that weigh a considerable amount and reciprocate at RPMs close to 7K...it's fairly rugged. Certainly I wouldn't advocate any situation whereas the car could "slip" off the jack and then introduce the possibility of damage to the case...it's more likely going to cause damage to your exhaust components, etc. <img src="graemlins/crying.gif" border="0" alt="[crying]" />
...that's why we have brought up the use of JACK STANDS many times in this post!
Robert, to answer your question, the "official lifting points" just aft of the doors are pretty much for lifting up the whole side of the vehicle. If you place jackstands under the jacking pads, you will pretty much have a "teeter-totter" situation - do you understand what I mean by that? Basically, the jack stands wind up being too forward and the weight of the engine tends to counterbalance the load...you and a friend could actually "rock, or teeter-totter" the car in this situation - NOT GOOD! <img src="graemlins/nono.gif" border="0" alt="[nono]" />
At the track, I often switch wheels from side to side, after a full day. Most tracks run clockwise, which encourages the use of a lot of right hand turns...so the Driver's side tires take quite a bit of wear when compared to the Passenger side...so I "flip" 'em after a day or so. This necessitated a procedure for switching the rears or the fronts at the same time...again, when "flipping" the fronts, I have to use two floor jacks.
Make sure that the 2 x 4 piece's grain runs from left to right and not fore and aft as the seam of the engine case and the weight involved will split it in two!
I wouldn't worry too much about causing damage to the engine case, it's pretty tough, after all it encapsulates a crank and rods that weigh a considerable amount and reciprocate at RPMs close to 7K...it's fairly rugged. Certainly I wouldn't advocate any situation whereas the car could "slip" off the jack and then introduce the possibility of damage to the case...it's more likely going to cause damage to your exhaust components, etc. <img src="graemlins/crying.gif" border="0" alt="[crying]" />
...that's why we have brought up the use of JACK STANDS many times in this post!
Robert, to answer your question, the "official lifting points" just aft of the doors are pretty much for lifting up the whole side of the vehicle. If you place jackstands under the jacking pads, you will pretty much have a "teeter-totter" situation - do you understand what I mean by that? Basically, the jack stands wind up being too forward and the weight of the engine tends to counterbalance the load...you and a friend could actually "rock, or teeter-totter" the car in this situation - NOT GOOD! <img src="graemlins/nono.gif" border="0" alt="[nono]" />
At the track, I often switch wheels from side to side, after a full day. Most tracks run clockwise, which encourages the use of a lot of right hand turns...so the Driver's side tires take quite a bit of wear when compared to the Passenger side...so I "flip" 'em after a day or so. This necessitated a procedure for switching the rears or the fronts at the same time...again, when "flipping" the fronts, I have to use two floor jacks.
