Rack and pinion in a 140.
Or more accurately in my case, 240 steering and suspension geometry and components in a 140.
Not for the faint hearted, I can tell you.
I started by making a new crossmember. I need to point out that the change from double wishbones to struts alters the strength requirements of the front end drastically, as the forces are acting in different directions. Before, the corssmember needed to be a pretty massive strutcutral member as it was taking all the suspension forces. This altered the design of the inner wings too, as the reinforcement that goes straight to the top of the crossmember is no longer required ( I was removing them anyway, but was concerned originally that I may have to replace them with something tubular). With a strut front end the majority of the suspension forces act upon the strut tower and not the chassis legs or crossmember. I'm not saying that there aren't forces on the legs, just that they are greatly reduced.
With that In mind I made a new crossmember and rack mounts. It's offset because there are major hassles with the column- more of which later:
Even with the rack mounted to it it weighs about half what the old crossmember did.
This done I carefully measured where the rack should be- taking into account that the distance between the lower ball joint and the track rod end is half an inch less on the 240 as opposed to the 140. Otherwise I would've ended up with the wheels half an inch too far back in the arches. Measurements made, I welded it into place. Here's a few pics showing the position and proximity to the sump. I have around half an inch of clearance (very stiff poly mounts, remember?):
Next I had to devise a way of connecting the rack to the original column. Here I've used a mixture of 740 and 940 parts because, well, they seemed the best fit. The fact that I get a collapsible section for safety is just a bonus!
I started by hacking off the end of the original column:
I then carefullt ground out the centre of the stump of column to accept the end of a 940 shaft (and killed angle grinder number five in the process.
):
The steel is lot thicker than it looks in those pictures!
With the 940 column a snug fit in the shaft I dummy built everything before tacking it into place. Satisfied that all fitted I welded it fully, and then ground it neatly, as it is a piece that will be clearly seen in the engine bay:
Et Voila! Rack and pinion steering!
One slight problem though. As some of you will know, the chassis legs on the 140 are closer together than the 240. This creates a problem whether you are doing this in right hand drive or wrong hand drive, as everything is mirrored. The problem? The column has to go through the chassis leg!
I've got round this by moving the chassis. C-ing is a term sometime used, I believe. I've had to cut all the way through to the outer skin of the leg to make everything fit, so I've made a box section to transfer loads and welded it on:
I need to puul the engine to do the same to the inside of the leg, but the engine hoist I've been looking after for a friend for the last year has just gone back to it's rightful owner. Arse.
To add to that I was going to pull the engine out myself today, but my back's been playing up of late and I didn't want to risk it. It's strong enough for the moment, although I wouldn't want to drive on it.
Next step is to make the lower arms and the upper rails to mount the struts to. I'll post it up when I've got more to tell.