Car jacking

[mtnjag]

This car is very sound but i have been frankly scared to use the factory jacking point due to all the horror stories i have read here and other sites on sill jacking.

Have made a wooden block for stabilization more than anything. Don’t need additional height. If i could crank the jack up more it would be more than adequate far short of full extension.

Confirming this is the same jack as you are using?

[mgcjag]

Hi Layne...have you read my post above re movement of the radius arm bush?....Steve

[mtnjag]

HimSteve,
Hmmm, yes i did and i responded but it doesn’t seem to be there. Sent it at same time as David responded.

Soooo,
Good idea on trying another car, should have thought of that. Think ill start with the front end of the Sprite. If it wont lift that then its obviously the jack.

I am using a block on the jack top that falls in between the radius arm flanges and pushes on the mounting bolt. Doesn’t seem to be moving jack or pressure point at all as car raises and radius arm drops, but I have not paid special attention as to possible binding and will now do so.

Early here so it will be a bit.

Layne

[JerryL770]

Remember what I said about the lever arm required to operate these jacks.

With the jack down the lever arm required to turn the crank handle is much higher then when the jack is up. Putting a block of wood between it and the car will obviously cause the jack to be more closed at the beginning of lift, increasing difficulty turning the crank.

If the effort you need to put into turning the crank handle is increasing as the jack goes up, there is something wrong with the jack or the jack setup. If it is being twisted by the increasing load maybe this is adding friction to the screw.

[mgcjag]

Hi Jerry...thats correct if you doing a straight lift of one end or one side.....but if you lift on a corner does the weight not increase as you go up becaus the other same side corner will also raise....if you continue lifling then the whole side will eventualy lift ......I have noticed this when lifting one corner with a trolly jack on my daily driver.....it gets harder to lift the higher you go.....Steve

[Series1 Stu]

Plus, the load on the jack increases from zero at the start of lifting to maximum once the car is clear of the ground (although complicated by the shifting centre of mass as the car moves under the action of the jack).

So, whilst a scissor jack requires less effort to lift a given load the higher it rises, the load on the jack is increasing as the load on the wheels/tyres is gradually transferred to it.

Still doesn't explain Layne's problem though............

[mtnjag]

I believe i understand what you are saying about jack function. The mechanical advantage increases as you raise the jack. More turns of the lead screw are required for an inch of lift, so as the full weight of the lift is placed on the jack it remains “easy” to operate.

Not experiencing that. It gets harder to operate as it rises and lifts the weight of the car. I placed the jack front and center on my sprite. I lifted it but it did get harder as the weight was increased on the jack as it lifted and became rather difficult as it took full weight of the front end.

Also, grabbed my balls and jacked the car at the sill factory jacking point. Lifted better than at the radius arm body mount bolt but very difficult to get rear tire off ground. Rear came off and it was too difficult to continue to crank in order to get front wheel off ground. I was on my knees turning as hard as i could.

(To be clear with no weight on the jack it operates smoothly throughout the range.)

So what do others experience with this jack at the factory sill point or other locations?? So far all I see is theory. What’s the reality of a lift.

[JerryL770]

.....but if you lift on a corner does the weight not increase as you go up because the other same side corner will also raise....if you continue lifting then the whole side will eventually lift ...........Steve

... yes of course Steve. Stupid of me, I should have realised but I'm still perplexed wrt Layne's problem

For myself, I purchased a series 3 BMW jack but this can only be used on the sill location. But I can confirm that it easily lifts my car sufficiently high to get a wheel on/off and will also easily lift from a flat type position.

[malcolm]

Must confess I bought a mini hydraulic bottle jack from Halfords, about £15, lifts 2 tons. Lifts either front wheel for tyre change very easy. On rear wheel, need to fiddle about a bit to get the height but ok and still dead easy.

[mtnjag]

Can someone report an actual use of the jack and the effort required to lift the car.
Also please note the location of the jacking point.

Is it easy to keep cranking, is it somewhat or very difficult as it actually lifts full weight?

[mgcjag]

Hi layne..cant get to my E at the moment its a 2+2 and i dont use the Porsche jack on it...however....not exactly what your asking..but i have a 900kg Porsche jack but with a different top mount...just jacked up both side wheels off the ground on my 4x4 from the front jack point.....had to put a fair bit of effort in but i have a short handle..Steve

[ralphr1780]

I have opted for this Porsche 928 jack, very compact and sturdy.
Have cut/filed the lifting nipple to a square shape, and fitted a hard plastic on top that now can fit into the original square lifting points on the car.
Tried it few times and it will lift the E without any sweating.

[mtnjag]

STeve, thats the same jack i have but with the top lug. Unlike you, i have a long “crank” and it’s still very hard with full weight on it ( smilely face here but i cant add emojis). Good example.

Ralph, at what points on the E do you lift?
I may take a look at that one.

Doesn’t seem like others have a problem with my jack but it seems to be in perfect shape and I hate to buy another and have the same result.

Thanks

[mgcjag]

Hi Layne...i doubt that anyone would use the porsch jack on the radius arm bush like you are trying to do....Ralph did mention in his post that he jacks in the original square lifting point.....I doubt there is anything wrong with your jack ..my thoughts are that your just expecting it to be easy to wind the handle were actually it needs more effort.....Steve

[mtnjag]

Yeah Steve, that's kinda my conclusion. I'm old but I'm not the weakest guy around. But I tried it on the sill point and was able to lift the car but I had to be on my knees with great effort. Maybe a bigger crank. ()

So I guess it's not in me and I'll have to try another option. I do have a cheap steel scissor jack I carry in my 62 Cutlass which lifts that car fine so I'll do a sanity check with that one and think about that 928 jack.

Can always use the 944 jack in the Sprite.

Thanks

[Gfhug]

Layne, I’ve just bought a 944 jack and lifting at the jacking lug it easily got the car to height to remove the wheels. The max height of the jack is the same as yours.
If you’re concerned about lifting at the sills why not do what I did and used a load spreading piece of wood. It is the same thickness as the lifting point of the jack so it didn’t increase effective the height.
And the higher the jack got the easier it seemed to be to operate it.
More weetabix needed

Geoff

PS David, thanks for the advice to buy one of these, but what do I do with the car it came with.

[mtnjag]

Wow, jusr the opposite for me. The higher the jack got when lifting the car the more difficulty in turning the crank, got VERY difficult.

BTW, i did lift at the sill jacking point with no ill effects, see my ealier post for results.