The car's mostly back together now, the wings and bonnet are still off because there are a couple of little issues that need attention. I'm making a new bracket for the fuel pump, I still need to bleed the brakes, and the gear change and exhaust will need modifying as a result of the 'box being about 40mm higher, also the handbrake lever doesn't fit as nicely against the back of the caliper as it used to, but I guess I can live with that.
It's sometimes a concern when fitting a GS/A engine, that lifting the gearbox over the axle can cause the rear bearings to not get enough oil. I don't think that will be a problem here as the bmw engine already sits quite high as a result of it's deep sump. At the moment the suspension is wound up quite high, nearly as high as standard, and the driveshafts are at the kind of angles normally only seen on 4x4s.

Previously the clearance between the alternator mounting 'loop', and the underside of the bonnet was about 10mm, lifting the back of the gearbox will have made this closer, I'll have to wait and see how much. It would be possible to cut off the bulky mounting and fabricate something smaller, this would also help if I want to fit a different alternator, which I might do. I can't find a bmw alternator that puts out more than 14v, a little more would be a benefit as the visa starter does struggle a bit tuning over the BM,

There's an electric fan behind the oil cooler which came from a GSXR 600, it's just about visible here http://i686.photobucket.com/albums/vv22 ... C10747.jpg . It works fine for stopping it from over heating when in traffic but doesn't make much difference when driving, and it does get too hot if driven hard on a hot day. I've got a second cooler to go in but had been waiting to do the gearbox first.

Your welding is tastier than tartiflette Joolz! I love what you're doing here, amazing stuff.

I dragged out the last few bits, but I think they're all done now. The exhaust swan neck got cut and re-welded and so did the gear linkage, the lever on the box got shortened a bit and now the lever in the car has got less travel, so I don't hit my knuckles on the wiper motor cover any more.

The only thing left is to try putting the bonnet on, I'm really pretty sure there's going to be trouble there, which is why I still haven't done it.


Anyway, while the wings are off, and I'm on a bit of a roll, I've got some 'porn' for you! This is an idea I've had in mind for some time, I had to spend some time filing the balls round on the steering arms for the MOT time before last, they were well overdue an overhaul but the price had put me off buying replacements. I spent a while deciding how this would work. It's a bit of luck that the threads on the ends of the track rods are an M14x1.25, the same as a spark plug thread, so no trouble finding someone with the right size tap.

I ended up with the following collection of bits, they are;

A pair of badly worn original arms, intercepted on their way between Simon's race car and the dustbin at last years 24H, thanks Simon.

Replacement arms cut from 10mm plate.

Top left, Two pieces of 20mm tube, bored out 13mm and threaded to fit the track rod at one end, plus two M16 nuts bored 20mm to fit over them

Top center, Two rose joints with M12x1.25 lefthand thread, with lock nuts and threaded bungs to suit, and two rubber boots. Bought from McGill Motorsports for about £40.

And two high tensile M12 bolts.



The old arms were sliced in half to reuse the lower piece which was then welded onto the new arms. At the other end an extra bit was welded on to give a thicker bit which was drilled and threaded M12.



The threaded bungs and tube were given a taper and then welded together, and the bored out nuts welded onto the tube.



The hub carriers were drilled and tapped out to M8, started through the old arm to keep it straight. Then the new arms were bolted on with high tensile bolts loctited in. I drilled the bolt heads for lock wire, but I think it's probably unnecessary.







They've been dismantled again to paint the adjusters and fit the rubber boot. The thing I'm wondering about now is the 12mm bolt holding the rose joint onto the arm, as it stands it will be simply loctited in, I'm wondering if the bolt should be long enough that it can be drilled for a split pin under the arm, or if I would have been better drilling a clearance hole in the arm and using a nyloc nut on it. Thoughts?

On the downside the new arms are heavier than the old ones, although by how much I don't actually know, I haven't got a suitable set of scales. I wondered if the lightening holes in them could have been bigger, or even if the whole center section could have been cut out. I wasn't sure at the time but erred on the side of caution, as you do with steering and brakes. It might have been nice to mill the middle out from both sides, leaving a couple of mm in the middle, to form a horizontal 'I' section, but I don't have access to a milling machine. Again, thoughts?

This set up has had the effect of lowering the ball joint pivot by 30mm, on a standard front suspension arm this probably would have caused the track rod to hit the suspension arm. But because I've got arms with modified castor angle this isn't a problem, in fact it's a benefit. Not only are they further from the wheel rims which had got a bit scraped by the old ones, but also the original set-up of having them higher than the kingpins exaggerates the effect of a worn kingpin. Having them lower as they are now will allow less movement of the wheel for a given amount of kingpin wear.

5590

http://www.myemoticons.com/images/emoti ... n-wave.gif

Only thing I'd wonder about is using Loctite on the arm to hub bolts, as it's a b#gger to remove the bolt stub if it did break.
If the pitch of the M8s is standard rather than fine, the clamping force may not be that much higher than with M7 x 1 pitch.

ken

p.s. Solidworks or...

Beautiful!

OOh sexy but youll start a whole lot of poorly executed copycats
what about a longer M12 and a nylock under the arm?
RE M8s in the hub.
When id done mine for the orange car i fitted the allen bolts dry and no locktite with a view to make locking keys from a couple of allen keys.......still in there and still no locking mech made yet ( took a big bag of spare bolts and they were checked every fuel stop all the way to Salbris)

As its in to a steel thread the M8 can take a fair bit more torque dont know the yeild of a 10.9 M7 but a 8.8 goes at 13 ftlbs - i tested a 12,9 M8 in a spare hub and took it up to 35ftlbs before the socket key started to go spiral so FT!

only fit bolts to the racers and never had trouble yet whereas the M7 and welded had cracked welds.

Sean

Yep,
cancel my earlier comment about clamping force, as 12.9 grade M8 are quids in...
http://www.cncexpo.com/MetricBoltTorque.aspx

ken

you're right this is 'PORN'

Excellent bit of work.
Need to build my own, as my balls are a bit worn out.

By moving the pivot point does that throw the ackermann principle all to cock or is it still geometrically the same in that respect? Doesn't that mean the steering is heavier if the arms have a shorter throw? Or have I misunderstood where the 30mm difference is?