Bump Steer

... or bumpsteer, arrrgh ... WHAT?
While chasing what possibly could make my car jump around on ruts, bumps and potholes like mad, I posted my questions in different forums, especially the german Seven-IG and the english WSCC-technical board. As always, the first answers get you more confused and you just feel dumb confronted with all that expertise. Then you start to read, ask more questions to those guys running theirs cars both on the road and the track.
The phenomenon is not easily explained, but I'll try. Imagine there is something wrong with your car's steering and/or suspension set-up. You drive around and you hit a pothole and the bumpsteer makes, like it says, that the car is steered in a different direction than your steering wheel points. As the affected wheel moves up and down, the wheel carrier moves in and out and steers the wheel. This is mostly due to a bad alignment of steering rack and wishbones.
Of course all this is far more complex and you could read your day (or week) away with expert literature. Two documents may catch your interest:
Doc 1
Doc 2
If you want more try the www or your nearest book shop.
Cheers.

Die hard, die harder

The estimated springrate of 275lbs/in is way too hard. I ordered a pair with 200lbs/in, set the tire pressure right and did some test drives with different toe-in. It is still a very harsh ride, but I'm getting closer to a good setup. I still have to see a pro for the best adjustments. Ride height is quite close to the road with 8cm.

A touch of yellow in the rape fields.
Cheers.

Tank venting valve

One of the reasons of MoT failure was a fuel leakage. On the top of the tank, I put some teflon tape on the threads of the fuel return line connection and the tank venting valve. Additionally, I connected a small piece of hose to the latter and guided it into the rollcage. The lower connection where the fuel is picked from the pump can only be taped when the tank is empty. For now I gave one more spin to the screwcap. Maybe this is enough, else I will drive as much as I can to empty the tank.
Cheers.

MoT (SNCT) - fail

The car didn't get approval from the technical authorities. The reasons are not severe. Two minor points not leading to failure, but mentioned on the report, are
- field of view (rock chips in wind screen)
- oil leakage ... also known as territory marking
The two important points are
- toe-in
- fuel leakage
The latter had been checked several times and I couldn't find any leakage. But then I filled the tank and drove the car and it showed that some of the connections on the tank are not consistent. I'll check that and will use some teflon tape to remedy.
Although I tried to set toe-in by myself, I didn't succeed. To be sure I will leave this job to a professional.
All in all the car is not very drivable concerning the suspension. It is very hard and follows every little bump and rut. Prior to set the toe-in, I will mount other springs with 200lbs/in rate. The oil temperature sender is dodgy as well and shows absurd values (46°C when cold, increasing up to 999°C).
Not yet finished, but close. Considering what else I changed on the car, I'm quite satisfied.
Cheers.

MoT postponed

More little works done since I had to postpone the MoT, awful weather ...
Next try will be on Saturday.
Cheers.

Resurrection

First drive since 18 months ... strange feeling, but great relief. Tomorrow MoT. Fingers crossed.
Cheers.

Cycle wings

The carbon look doesn't match my car's style, I intend to paint them yellow eventually. The goal was to have them the nearest possible to the rubber. Therefore I had to bend the cycle wing stays. The old fashioned look with the rounded tops makes that there is a difference in height, the stays being designed for the modern look flat top wings.With Morgan in mind, I thought that a little bit of wood is ok for my car, so now the spacers are made of timber (painted black after the pics had been taken).

Hot air vent covered with some mesh to prevent inquisitive looks.

Overall appearance ok on photos, but still some work to do before it is completely finished (if ever).
Cheers.

Toe in - toe out

Set the toe today, which is quite a lot of work if you have to adapt the parts prior to assembly and setup. First I had to cut the steering rack extensions. Those provided from Westfield with the wide track kit are a little bit too long, I cut three threads on every side. Then there is only one half nut delivered per side. To fix the extensions you need two. Starting from a full nut, I lathed two more.

Toe in toe out can now be set and after some driving controlled again and set anew if required. The graph shows what exactly this setting means. It is mostly responsible for the cars ability to corner. Toe out makes the car turn easier, toe in gives better straight on stability. The graph shows extreme settings, in reality we talk about 1 or 2 degrees.

The steering hub is covered with a bellow to prevent dust and dirt to enter.
Cheers.