Method for central lifting

[rossbraithwaite]

What is the recognised or preferred method for lifting an E Type by jacking centrally? I am aware of the risk of damage to the picture frame and the diff carrier if used as jacking points. Is there an acceptable method of lifting the car centrally? What is the preferred location for axle stands front and rear once the car is up?

[Moeregaard]

I've always avoided using the factory jacking points in the sill, since they've been known to collapse. The old method of placing a short length of hardwood (oak being my favorite) in the bottom channel of the picture frame still works. For the rear, an 18" length of 4" X 4" fencepost placed between the exhaust pipes will distribute the load and prevent damage to the diff carrier.

If the wheels are not going to be removed, I prefer to have at least one end of the car supported by ramps placed under the wheels before raising the other end of the car. This will prevent the car from walking off the jackstands while the other end is raised. If the wheels are to be removed, stands may be placed under the A-arm trunnions in front and the floor stiffeners at the rear bulkhead. Definitely leave the trolley jack in place while working under the car.

[jag68]

They can be jacked on the torsion bar reaction tie plate if you have a trolley hydraulic jack. I've been doing this for years on my '68 ots. A friend who has a Jag service shop has as well. If necessary I use a small bottle jack under the jacking point by the rocker to lift the car up enough to get the jack under it. When you lower the car onto the wheels it will sit somewhat higher because the front wheels have gone into positive camber from being off the floor, and usually this is enough to clear the jack without reusing the bottle jack.

[christopher storey]

I do not like the idea of jacking under the reaction plate at all. It will impose wholly undesigned stresses on the torsion bars, potentially applying a bending moment for which they are quite unsuited

[jag68]

Well Chris I've owned five E Types over the past 45 years and have done it numerous times on all five. My service technician friend from whom I learned the technique has done it for the past 30 plus years on hundreds of cars. The plate is bolted to the body (cowl - which is very stiff)) in six different places and is very robust. It would have to move to impose stress on the bars, and if it's bolted in and moving you have some real serious problems.

[christopher storey]

In 40 years of playing with E types, you, and your technician , are the only people I have ever heard suggest that this was a suitable lifting point. The factory indicate ( see e.g J15 in the workshop manual ) that if the front suspension is to be used as a lifting point, the only suitable point is the rear wishbone mounting point. But then, what did the factory know? The mechanics are in fact quite simple : the transverse fixing of the reaction plate to the body frame is displaced to the rear by about 1 inch/25 mm and at a level slightly below that horizontal plane of the torsion bar bracket . The longitudinal fixings are only to a very thin bracket on each side, and of course to the torsion bar . Therefore , if you jack under the reaction plate there is imposed a rotational moment on the thin brackets and therefore a bending moment to the torsion bars. It may not be very great ( although given the weight it is not insignificant ) , and the actual movement may be minimal , but it is a force which the torsion bars are, as I said intially, wholly undesigned to withstand - they are there to be twisted, not bent

[jag68]

Chris it's not my intention to get into a debating contest here, so this is my last response. I have a practice that's worked for me for many years and many cars - you have a theory. Part of your theory that the torsion bars are not bent is simply wrong. First look along the length of the bar on a stationary car, and you will see that they are actually bent on an inward arc. If you have ever tried to install a torsion bar you will recall, I'm sure, that if you start with the front of the bar in the control arm and then try to put the rear bracket over the rear splines and into the hole of the tie plate you actually have to pry the rear of the bar over to get the bracket to slip into the hole in the tie plate. Secondly as the connection point for the torsion bar on the front control arm is inboard of the pivot point of the control arm the connection point on the arm moves up and down vertically (actually in an arc ) as the wheel goes up and down, so it has to bend the torsion bar back to the rear mounting when it does this - yes and twist it too. Any theoretical movement of the plate by jacking on the plate would never be even close to the bending of the bar as you go down the road. My workshop manual was purchased from Jaguar with the car in 1968. Page J15 in this manual doesn't say anything about jacking the car, although it does say the weight of the car can be supported on the lower wishbone fulcrum support bracket, a practice that I follow. I can't therefore respond to your comment on what the factory says other than to point out from your recital of it that I'm not suggesting jacking the car via the front suspension which seems to condition the remark about using the rear wishbone mounting bracket. (I do use that bracket when the car is on my two post lift.)

[christopher storey]

Your point about the front of the bar moving in an arc, and therefore creating a logitudinal bending in the bar is well made . If the practice you have adopted works for you, fine . I still will not recommend it to others based on your theory : I prefer mine ! :)

[rossbraithwaite]

Thanks for the responses and lively debate. I just wanted to check that my current method is acceptable; rear up first jacking through the hole in the diff carrier with the help of a wooden block. Front up second jacking under the picture frame with the help of a wooden baton. Rear axle stands under the half shafts and front axle stands under the wishbone fulcrum boss.